--- jsr166/src/jsr166e/ConcurrentHashMapV8.java 2011/09/09 13:02:01 1.16 +++ jsr166/src/jsr166e/ConcurrentHashMapV8.java 2013/07/19 19:34:43 1.111 @@ -5,21 +5,29 @@ */ package jsr166e; -import jsr166e.LongAdder; -import java.util.Map; -import java.util.Set; + +import jsr166e.ForkJoinPool; + +import java.io.ObjectStreamField; +import java.io.Serializable; +import java.lang.reflect.ParameterizedType; +import java.lang.reflect.Type; +import java.util.Arrays; import java.util.Collection; -import java.util.AbstractMap; -import java.util.AbstractSet; -import java.util.AbstractCollection; -import java.util.Hashtable; +import java.util.Comparator; +import java.util.ConcurrentModificationException; +import java.util.Enumeration; import java.util.HashMap; +import java.util.Hashtable; import java.util.Iterator; -import java.util.Enumeration; -import java.util.ConcurrentModificationException; +import java.util.Map; import java.util.NoSuchElementException; +import java.util.Set; import java.util.concurrent.ConcurrentMap; -import java.io.Serializable; +import java.util.concurrent.atomic.AtomicReference; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.locks.LockSupport; +import java.util.concurrent.locks.ReentrantLock; /** * A hash table supporting full concurrency of retrievals and @@ -33,33 +41,37 @@ import java.io.Serializable; * interoperable with {@code Hashtable} in programs that rely on its * thread safety but not on its synchronization details. * - *

Retrieval operations (including {@code get}) generally do not + *

Retrieval operations (including {@code get}) generally do not * block, so may overlap with update operations (including {@code put} * and {@code remove}). Retrievals reflect the results of the most * recently completed update operations holding upon their - * onset. For aggregate operations such as {@code putAll} and {@code - * clear}, concurrent retrievals may reflect insertion or removal of - * only some entries. Similarly, Iterators and Enumerations return - * elements reflecting the state of the hash table at some point at or - * since the creation of the iterator/enumeration. They do - * not throw {@link ConcurrentModificationException}. - * However, iterators are designed to be used by only one thread at a - * time. Bear in mind that the results of aggregate status methods - * including {@code size}, {@code isEmpty}, and {@code containsValue} - * are typically useful only when a map is not undergoing concurrent - * updates in other threads. Otherwise the results of these methods - * reflect transient states that may be adequate for monitoring - * or estimation purposes, but not for program control. + * onset. (More formally, an update operation for a given key bears a + * happens-before relation with any (non-null) retrieval for + * that key reporting the updated value.) For aggregate operations + * such as {@code putAll} and {@code clear}, concurrent retrievals may + * reflect insertion or removal of only some entries. Similarly, + * Iterators and Enumerations return elements reflecting the state of + * the hash table at some point at or since the creation of the + * iterator/enumeration. They do not throw {@link + * ConcurrentModificationException}. However, iterators are designed + * to be used by only one thread at a time. Bear in mind that the + * results of aggregate status methods including {@code size}, {@code + * isEmpty}, and {@code containsValue} are typically useful only when + * a map is not undergoing concurrent updates in other threads. + * Otherwise the results of these methods reflect transient states + * that may be adequate for monitoring or estimation purposes, but not + * for program control. * - *

The table is dynamically expanded when there are too many + *

The table is dynamically expanded when there are too many * collisions (i.e., keys that have distinct hash codes but fall into * the same slot modulo the table size), with the expected average - * effect of maintaining roughly two bins per mapping. There may be - * much variance around this average as mappings are added and - * removed, but overall, this maintains a commonly accepted time/space - * tradeoff for hash tables. However, resizing this or any other kind - * of hash table may be a relatively slow operation. When possible, it - * is a good idea to provide a size estimate as an optional {@code + * effect of maintaining roughly two bins per mapping (corresponding + * to a 0.75 load factor threshold for resizing). There may be much + * variance around this average as mappings are added and removed, but + * overall, this maintains a commonly accepted time/space tradeoff for + * hash tables. However, resizing this or any other kind of hash + * table may be a relatively slow operation. When possible, it is a + * good idea to provide a size estimate as an optional {@code * initialCapacity} constructor argument. An additional optional * {@code loadFactor} constructor argument provides a further means of * customizing initial table capacity by specifying the table density @@ -68,52 +80,200 @@ import java.io.Serializable; * versions of this class, constructors may optionally specify an * expected {@code concurrencyLevel} as an additional hint for * internal sizing. Note that using many keys with exactly the same - * {@code hashCode{}} is a sure way to slow down performance of any - * hash table. + * {@code hashCode()} is a sure way to slow down performance of any + * hash table. To ameliorate impact, when keys are {@link Comparable}, + * this class may use comparison order among keys to help break ties. + * + *

A {@link Set} projection of a ConcurrentHashMapV8 may be created + * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed + * (using {@link #keySet(Object)} when only keys are of interest, and the + * mapped values are (perhaps transiently) not used or all take the + * same mapping value. * *

This class and its views and iterators implement all of the * optional methods of the {@link Map} and {@link Iterator} * interfaces. * - *

Like {@link Hashtable} but unlike {@link HashMap}, this class + *

Like {@link Hashtable} but unlike {@link HashMap}, this class * does not allow {@code null} to be used as a key or value. * + *

ConcurrentHashMapV8s support a set of sequential and parallel bulk + * operations that are designed + * to be safely, and often sensibly, applied even with maps that are + * being concurrently updated by other threads; for example, when + * computing a snapshot summary of the values in a shared registry. + * There are three kinds of operation, each with four forms, accepting + * functions with Keys, Values, Entries, and (Key, Value) arguments + * and/or return values. Because the elements of a ConcurrentHashMapV8 + * are not ordered in any particular way, and may be processed in + * different orders in different parallel executions, the correctness + * of supplied functions should not depend on any ordering, or on any + * other objects or values that may transiently change while + * computation is in progress; and except for forEach actions, should + * ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry} + * objects do not support method {@code setValue}. + * + *

+ * + *

These bulk operations accept a {@code parallelismThreshold} + * argument. Methods proceed sequentially if the current map size is + * estimated to be less than the given threshold. Using a value of + * {@code Long.MAX_VALUE} suppresses all parallelism. Using a value + * of {@code 1} results in maximal parallelism by partitioning into + * enough subtasks to fully utilize the {@link + * ForkJoinPool#commonPool()} that is used for all parallel + * computations. Normally, you would initially choose one of these + * extreme values, and then measure performance of using in-between + * values that trade off overhead versus throughput. + * + *

The concurrency properties of bulk operations follow + * from those of ConcurrentHashMapV8: Any non-null result returned + * from {@code get(key)} and related access methods bears a + * happens-before relation with the associated insertion or + * update. The result of any bulk operation reflects the + * composition of these per-element relations (but is not + * necessarily atomic with respect to the map as a whole unless it + * is somehow known to be quiescent). Conversely, because keys + * and values in the map are never null, null serves as a reliable + * atomic indicator of the current lack of any result. To + * maintain this property, null serves as an implicit basis for + * all non-scalar reduction operations. For the double, long, and + * int versions, the basis should be one that, when combined with + * any other value, returns that other value (more formally, it + * should be the identity element for the reduction). Most common + * reductions have these properties; for example, computing a sum + * with basis 0 or a minimum with basis MAX_VALUE. + * + *

Search and transformation functions provided as arguments + * should similarly return null to indicate the lack of any result + * (in which case it is not used). In the case of mapped + * reductions, this also enables transformations to serve as + * filters, returning null (or, in the case of primitive + * specializations, the identity basis) if the element should not + * be combined. You can create compound transformations and + * filterings by composing them yourself under this "null means + * there is nothing there now" rule before using them in search or + * reduce operations. + * + *

Methods accepting and/or returning Entry arguments maintain + * key-value associations. They may be useful for example when + * finding the key for the greatest value. Note that "plain" Entry + * arguments can be supplied using {@code new + * AbstractMap.SimpleEntry(k,v)}. + * + *

Bulk operations may complete abruptly, throwing an + * exception encountered in the application of a supplied + * function. Bear in mind when handling such exceptions that other + * concurrently executing functions could also have thrown + * exceptions, or would have done so if the first exception had + * not occurred. + * + *

Speedups for parallel compared to sequential forms are common + * but not guaranteed. Parallel operations involving brief functions + * on small maps may execute more slowly than sequential forms if the + * underlying work to parallelize the computation is more expensive + * than the computation itself. Similarly, parallelization may not + * lead to much actual parallelism if all processors are busy + * performing unrelated tasks. + * + *

All arguments to all task methods must be non-null. + * + *

jsr166e note: During transition, this class + * uses nested functional interfaces with different names but the + * same forms as those expected for JDK8. + * *

This class is a member of the * * Java Collections Framework. * - *

jsr166e note: This class is a candidate replacement for - * java.util.concurrent.ConcurrentHashMap. - * * @since 1.5 * @author Doug Lea * @param the type of keys maintained by this map * @param the type of mapped values */ -public class ConcurrentHashMapV8 - implements ConcurrentMap, Serializable { +public class ConcurrentHashMapV8 + implements ConcurrentMap, Serializable { private static final long serialVersionUID = 7249069246763182397L; /** - * A function computing a mapping from the given key to a value, - * or {@code null} if there is no mapping. This is a place-holder - * for an upcoming JDK8 interface. - */ - public static interface MappingFunction { - /** - * Returns a value for the given key, or null if there is no - * mapping. If this function throws an (unchecked) exception, - * the exception is rethrown to its caller, and no mapping is - * recorded. Because this function is invoked within - * atomicity control, the computation should be short and - * simple. The most common usage is to construct a new object - * serving as an initial mapped value. - * - * @param key the (non-null) key - * @return a value, or null if none + * An object for traversing and partitioning elements of a source. + * This interface provides a subset of the functionality of JDK8 + * java.util.Spliterator. + */ + public static interface ConcurrentHashMapSpliterator { + /** + * If possible, returns a new spliterator covering + * approximately one half of the elements, which will not be + * covered by this spliterator. Returns null if cannot be + * split. */ - V map(K key); - } + ConcurrentHashMapSpliterator trySplit(); + /** + * Returns an estimate of the number of elements covered by + * this Spliterator. + */ + long estimateSize(); + + /** Applies the action to each untraversed element */ + void forEachRemaining(Action action); + /** If an element remains, applies the action and returns true. */ + boolean tryAdvance(Action action); + } + + // Sams + /** Interface describing a void action of one argument */ + public interface Action { void apply(A a); } + /** Interface describing a void action of two arguments */ + public interface BiAction { void apply(A a, B b); } + /** Interface describing a function of one argument */ + public interface Fun { T apply(A a); } + /** Interface describing a function of two arguments */ + public interface BiFun { T apply(A a, B b); } + /** Interface describing a function mapping its argument to a double */ + public interface ObjectToDouble { double apply(A a); } + /** Interface describing a function mapping its argument to a long */ + public interface ObjectToLong { long apply(A a); } + /** Interface describing a function mapping its argument to an int */ + public interface ObjectToInt {int apply(A a); } + /** Interface describing a function mapping two arguments to a double */ + public interface ObjectByObjectToDouble { double apply(A a, B b); } + /** Interface describing a function mapping two arguments to a long */ + public interface ObjectByObjectToLong { long apply(A a, B b); } + /** Interface describing a function mapping two arguments to an int */ + public interface ObjectByObjectToInt {int apply(A a, B b); } + /** Interface describing a function mapping two doubles to a double */ + public interface DoubleByDoubleToDouble { double apply(double a, double b); } + /** Interface describing a function mapping two longs to a long */ + public interface LongByLongToLong { long apply(long a, long b); } + /** Interface describing a function mapping two ints to an int */ + public interface IntByIntToInt { int apply(int a, int b); } /* * Overview: @@ -121,128 +281,216 @@ public class ConcurrentHashMapV8 * The primary design goal of this hash table is to maintain * concurrent readability (typically method get(), but also * iterators and related methods) while minimizing update - * contention. - * - * Each key-value mapping is held in a Node. Because Node fields - * can contain special values, they are defined using plain Object - * types. Similarly in turn, all internal methods that use them - * work off Object types. And similarly, so do the internal - * methods of auxiliary iterator and view classes. All public - * generic typed methods relay in/out of these internal methods, - * supplying null-checks and casts as needed. + * contention. Secondary goals are to keep space consumption about + * the same or better than java.util.HashMap, and to support high + * initial insertion rates on an empty table by many threads. + * + * This map usually acts as a binned (bucketed) hash table. Each + * key-value mapping is held in a Node. Most nodes are instances + * of the basic Node class with hash, key, value, and next + * fields. However, various subclasses exist: TreeNodes are + * arranged in balanced trees, not lists. TreeBins hold the roots + * of sets of TreeNodes. ForwardingNodes are placed at the heads + * of bins during resizing. ReservationNodes are used as + * placeholders while establishing values in computeIfAbsent and + * related methods. The types TreeBin, ForwardingNode, and + * ReservationNode do not hold normal user keys, values, or + * hashes, and are readily distinguishable during search etc + * because they have negative hash fields and null key and value + * fields. (These special nodes are either uncommon or transient, + * so the impact of carrying around some unused fields is + * insignificant.) * * The table is lazily initialized to a power-of-two size upon the - * first insertion. Each bin in the table contains a list of - * Nodes (most often, zero or one Node). Table accesses require - * volatile/atomic reads, writes, and CASes. Because there is no - * other way to arrange this without adding further indirections, - * we use intrinsics (sun.misc.Unsafe) operations. The lists of - * nodes within bins are always accurately traversable under - * volatile reads, so long as lookups check hash code and - * non-nullness of value before checking key equality. (All valid - * hash codes are nonnegative. Negative values are reserved for - * special forwarding nodes; see below.) + * first insertion. Each bin in the table normally contains a + * list of Nodes (most often, the list has only zero or one Node). + * Table accesses require volatile/atomic reads, writes, and + * CASes. Because there is no other way to arrange this without + * adding further indirections, we use intrinsics + * (sun.misc.Unsafe) operations. + * + * We use the top (sign) bit of Node hash fields for control + * purposes -- it is available anyway because of addressing + * constraints. Nodes with negative hash fields are specially + * handled or ignored in map methods. * - * Insertion (via put or putIfAbsent) of the first node in an + * Insertion (via put or its variants) of the first node in an * empty bin is performed by just CASing it to the bin. This is - * on average by far the most common case for put operations. - * Other update operations (insert, delete, and replace) require - * locks. We do not want to waste the space required to associate - * a distinct lock object with each bin, so instead use the first - * node of a bin list itself as a lock, using plain "synchronized" - * locks. These save space and we can live with block-structured - * lock/unlock operations. Using the first node of a list as a - * lock does not by itself suffice though: When a node is locked, - * any update must first validate that it is still the first node, - * and retry if not. Because new nodes are always appended to - * lists, once a node is first in a bin, it remains first until - * deleted or the bin becomes invalidated. However, operations - * that only conditionally update can and sometimes do inspect - * nodes until the point of update. This is a converse of sorts to - * the lazy locking technique described by Herlihy & Shavit. + * by far the most common case for put operations under most + * key/hash distributions. Other update operations (insert, + * delete, and replace) require locks. We do not want to waste + * the space required to associate a distinct lock object with + * each bin, so instead use the first node of a bin list itself as + * a lock. Locking support for these locks relies on builtin + * "synchronized" monitors. + * + * Using the first node of a list as a lock does not by itself + * suffice though: When a node is locked, any update must first + * validate that it is still the first node after locking it, and + * retry if not. Because new nodes are always appended to lists, + * once a node is first in a bin, it remains first until deleted + * or the bin becomes invalidated (upon resizing). * - * The main disadvantage of this approach is that most update + * The main disadvantage of per-bin locks is that other update * operations on other nodes in a bin list protected by the same * lock can stall, for example when user equals() or mapping - * functions take a long time. However, statistically, this is - * not a common enough problem to outweigh the time/space overhead - * of alternatives: Under random hash codes, the frequency of - * nodes in bins follows a Poisson distribution + * functions take a long time. However, statistically, under + * random hash codes, this is not a common problem. Ideally, the + * frequency of nodes in bins follows a Poisson distribution * (http://en.wikipedia.org/wiki/Poisson_distribution) with a * parameter of about 0.5 on average, given the resizing threshold * of 0.75, although with a large variance because of resizing * granularity. Ignoring variance, the expected occurrences of * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The - * first few values are: + * first values are: * - * 0: 0.607 - * 1: 0.303 - * 2: 0.076 - * 3: 0.012 - * more: 0.002 + * 0: 0.60653066 + * 1: 0.30326533 + * 2: 0.07581633 + * 3: 0.01263606 + * 4: 0.00157952 + * 5: 0.00015795 + * 6: 0.00001316 + * 7: 0.00000094 + * 8: 0.00000006 + * more: less than 1 in ten million * * Lock contention probability for two threads accessing distinct - * elements is roughly 1 / (8 * #elements). Function "spread" - * performs hashCode randomization that improves the likelihood - * that these assumptions hold unless users define exactly the - * same value for too many hashCodes. - * - * The table is resized when occupancy exceeds a threshold. Only - * a single thread performs the resize (using field "resizing", to - * arrange exclusion), but the table otherwise remains usable for - * reads and updates. Resizing proceeds by transferring bins, one - * by one, from the table to the next table. Upon transfer, the - * old table bin contains only a special forwarding node (with - * negative hash field) that contains the next table as its - * key. On encountering a forwarding node, access and update - * operations restart, using the new table. To ensure concurrent - * readability of traversals, transfers must proceed from the last - * bin (table.length - 1) up towards the first. Upon seeing a - * forwarding node, traversals (see class InternalIterator) - * arrange to move to the new table for the rest of the traversal - * without revisiting nodes. This constrains bin transfers to a - * particular order, and so can block indefinitely waiting for the - * next lock, and other threads cannot help with the transfer. - * However, expected stalls are infrequent enough to not warrant - * the additional overhead of access and iteration schemes that - * could admit out-of-order or concurrent bin transfers. - * - * This traversal scheme also applies to partial traversals of - * ranges of bins (via an alternate InternalIterator constructor) - * to support partitioned aggregate operations (that are not - * otherwise implemented yet). Also, read-only operations give up - * if ever forwarded to a null table, which provides support for - * shutdown-style clearing, which is also not currently - * implemented. + * elements is roughly 1 / (8 * #elements) under random hashes. + * + * Actual hash code distributions encountered in practice + * sometimes deviate significantly from uniform randomness. This + * includes the case when N > (1<<30), so some keys MUST collide. + * Similarly for dumb or hostile usages in which multiple keys are + * designed to have identical hash codes or ones that differs only + * in masked-out high bits. So we use a secondary strategy that + * applies when the number of nodes in a bin exceeds a + * threshold. These TreeBins use a balanced tree to hold nodes (a + * specialized form of red-black trees), bounding search time to + * O(log N). Each search step in a TreeBin is at least twice as + * slow as in a regular list, but given that N cannot exceed + * (1<<64) (before running out of addresses) this bounds search + * steps, lock hold times, etc, to reasonable constants (roughly + * 100 nodes inspected per operation worst case) so long as keys + * are Comparable (which is very common -- String, Long, etc). + * TreeBin nodes (TreeNodes) also maintain the same "next" + * traversal pointers as regular nodes, so can be traversed in + * iterators in the same way. + * + * The table is resized when occupancy exceeds a percentage + * threshold (nominally, 0.75, but see below). Any thread + * noticing an overfull bin may assist in resizing after the + * initiating thread allocates and sets up the replacement + * array. However, rather than stalling, these other threads may + * proceed with insertions etc. The use of TreeBins shields us + * from the worst case effects of overfilling while resizes are in + * progress. Resizing proceeds by transferring bins, one by one, + * from the table to the next table. To enable concurrency, the + * next table must be (incrementally) prefilled with place-holders + * serving as reverse forwarders to the old table. Because we are + * using power-of-two expansion, the elements from each bin must + * either stay at same index, or move with a power of two + * offset. We eliminate unnecessary node creation by catching + * cases where old nodes can be reused because their next fields + * won't change. On average, only about one-sixth of them need + * cloning when a table doubles. The nodes they replace will be + * garbage collectable as soon as they are no longer referenced by + * any reader thread that may be in the midst of concurrently + * traversing table. Upon transfer, the old table bin contains + * only a special forwarding node (with hash field "MOVED") that + * contains the next table as its key. On encountering a + * forwarding node, access and update operations restart, using + * the new table. + * + * Each bin transfer requires its bin lock, which can stall + * waiting for locks while resizing. However, because other + * threads can join in and help resize rather than contend for + * locks, average aggregate waits become shorter as resizing + * progresses. The transfer operation must also ensure that all + * accessible bins in both the old and new table are usable by any + * traversal. This is arranged by proceeding from the last bin + * (table.length - 1) up towards the first. Upon seeing a + * forwarding node, traversals (see class Traverser) arrange to + * move to the new table without revisiting nodes. However, to + * ensure that no intervening nodes are skipped, bin splitting can + * only begin after the associated reverse-forwarders are in + * place. + * + * The traversal scheme also applies to partial traversals of + * ranges of bins (via an alternate Traverser constructor) + * to support partitioned aggregate operations. Also, read-only + * operations give up if ever forwarded to a null table, which + * provides support for shutdown-style clearing, which is also not + * currently implemented. * * Lazy table initialization minimizes footprint until first use, * and also avoids resizings when the first operation is from a * putAll, constructor with map argument, or deserialization. - * These cases attempt to override the targetCapacity used in - * growTable. These harmlessly fail to take effect in cases of - * races with other ongoing resizings. Uses of the threshold and - * targetCapacity during attempted initializations or resizings - * are racy but fall back on checks to preserve correctness. - * - * The element count is maintained using a LongAdder, which avoids - * contention on updates but can encounter cache thrashing if read - * too frequently during concurrent access. To avoid reading so - * often, resizing is normally attempted only upon adding to a bin - * already holding two or more nodes. Under uniform hash + * These cases attempt to override the initial capacity settings, + * but harmlessly fail to take effect in cases of races. + * + * The element count is maintained using a specialization of + * LongAdder. We need to incorporate a specialization rather than + * just use a LongAdder in order to access implicit + * contention-sensing that leads to creation of multiple + * CounterCells. The counter mechanics avoid contention on + * updates but can encounter cache thrashing if read too + * frequently during concurrent access. To avoid reading so often, + * resizing under contention is attempted only upon adding to a + * bin already holding two or more nodes. Under uniform hash * distributions, the probability of this occurring at threshold * is around 13%, meaning that only about 1 in 8 puts check - * threshold (and after resizing, many fewer do so). But this - * approximation has high variance for small table sizes, so we - * check on any collision for sizes <= 64. Further, to increase - * the probability that a resize occurs soon enough, we offset the - * threshold (see THRESHOLD_OFFSET) by the expected number of puts - * between checks. + * threshold (and after resizing, many fewer do so). + * + * TreeBins use a special form of comparison for search and + * related operations (which is the main reason we cannot use + * existing collections such as TreeMaps). TreeBins contain + * Comparable elements, but may contain others, as well as + * elements that are Comparable but not necessarily Comparable + * for the same T, so we cannot invoke compareTo among them. To + * handle this, the tree is ordered primarily by hash value, then + * by Comparable.compareTo order if applicable. On lookup at a + * node, if elements are not comparable or compare as 0 then both + * left and right children may need to be searched in the case of + * tied hash values. (This corresponds to the full list search + * that would be necessary if all elements were non-Comparable and + * had tied hashes.) The red-black balancing code is updated from + * pre-jdk-collections + * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) + * based in turn on Cormen, Leiserson, and Rivest "Introduction to + * Algorithms" (CLR). + * + * TreeBins also require an additional locking mechanism. While + * list traversal is always possible by readers even during + * updates, tree traversal is not, mainly because of tree-rotations + * that may change the root node and/or its linkages. TreeBins + * include a simple read-write lock mechanism parasitic on the + * main bin-synchronization strategy: Structural adjustments + * associated with an insertion or removal are already bin-locked + * (and so cannot conflict with other writers) but must wait for + * ongoing readers to finish. Since there can be only one such + * waiter, we use a simple scheme using a single "waiter" field to + * block writers. However, readers need never block. If the root + * lock is held, they proceed along the slow traversal path (via + * next-pointers) until the lock becomes available or the list is + * exhausted, whichever comes first. These cases are not fast, but + * maximize aggregate expected throughput. * * Maintaining API and serialization compatibility with previous * versions of this class introduces several oddities. Mainly: We * leave untouched but unused constructor arguments refering to - * concurrencyLevel. We also declare an unused "Segment" class - * that is instantiated in minimal form only when serializing. + * concurrencyLevel. We accept a loadFactor constructor argument, + * but apply it only to initial table capacity (which is the only + * time that we can guarantee to honor it.) We also declare an + * unused "Segment" class that is instantiated in minimal form + * only when serializing. + * + * This file is organized to make things a little easier to follow + * while reading than they might otherwise: First the main static + * declarations and utilities, then fields, then main public + * methods (with a few factorings of multiple public methods into + * internal ones), then sizing methods, trees, traversers, and + * bulk operations. */ /* ---------------- Constants -------------- */ @@ -250,7 +498,9 @@ public class ConcurrentHashMapV8 /** * The largest possible table capacity. This value must be * exactly 1<<30 to stay within Java array allocation and indexing - * bounds for power of two table sizes. + * bounds for power of two table sizes, and is further required + * because the top two bits of 32bit hash fields are used for + * control purposes. */ private static final int MAXIMUM_CAPACITY = 1 << 30; @@ -261,112 +511,157 @@ public class ConcurrentHashMapV8 private static final int DEFAULT_CAPACITY = 16; /** + * The largest possible (non-power of two) array size. + * Needed by toArray and related methods. + */ + static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; + + /** + * The default concurrency level for this table. Unused but + * defined for compatibility with previous versions of this class. + */ + private static final int DEFAULT_CONCURRENCY_LEVEL = 16; + + /** * The load factor for this table. Overrides of this value in * constructors affect only the initial table capacity. The - * actual floating point value isn't normally used, because it is - * simpler to rely on the expression {@code n - (n >>> 2)} for the - * associated resizing threshold. + * actual floating point value isn't normally used -- it is + * simpler to use expressions such as {@code n - (n >>> 2)} for + * the associated resizing threshold. */ private static final float LOAD_FACTOR = 0.75f; /** - * The count value to offset thresholds to compensate for checking - * for the need to resize only when inserting into bins with two - * or more elements. See above for explanation. + * The bin count threshold for using a tree rather than list for a + * bin. Bins are converted to trees when adding an element to a + * bin with at least this many nodes. The value must be greater + * than 2, and should be at least 8 to mesh with assumptions in + * tree removal about conversion back to plain bins upon + * shrinkage. */ - private static final int THRESHOLD_OFFSET = 8; + static final int TREEIFY_THRESHOLD = 8; /** - * The default concurrency level for this table. Unused except as - * a sizing hint, but defined for compatibility with previous - * versions of this class. + * The bin count threshold for untreeifying a (split) bin during a + * resize operation. Should be less than TREEIFY_THRESHOLD, and at + * most 6 to mesh with shrinkage detection under removal. */ - private static final int DEFAULT_CONCURRENCY_LEVEL = 16; + static final int UNTREEIFY_THRESHOLD = 6; + + /** + * The smallest table capacity for which bins may be treeified. + * (Otherwise the table is resized if too many nodes in a bin.) + * The value should be at least 4 * TREEIFY_THRESHOLD to avoid + * conflicts between resizing and treeification thresholds. + */ + static final int MIN_TREEIFY_CAPACITY = 64; + + /** + * Minimum number of rebinnings per transfer step. Ranges are + * subdivided to allow multiple resizer threads. This value + * serves as a lower bound to avoid resizers encountering + * excessive memory contention. The value should be at least + * DEFAULT_CAPACITY. + */ + private static final int MIN_TRANSFER_STRIDE = 16; + + /* + * Encodings for Node hash fields. See above for explanation. + */ + static final int MOVED = -1; // hash for forwarding nodes + static final int TREEBIN = -2; // hash for roots of trees + static final int RESERVED = -3; // hash for transient reservations + static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash + + /** Number of CPUS, to place bounds on some sizings */ + static final int NCPU = Runtime.getRuntime().availableProcessors(); + + /** For serialization compatibility. */ + private static final ObjectStreamField[] serialPersistentFields = { + new ObjectStreamField("segments", Segment[].class), + new ObjectStreamField("segmentMask", Integer.TYPE), + new ObjectStreamField("segmentShift", Integer.TYPE) + }; /* ---------------- Nodes -------------- */ /** - * Key-value entry. Note that this is never exported out as a - * user-visible Map.Entry. Nodes with a negative hash field are - * special, and do not contain user keys or values. Otherwise, - * keys are never null, and null val fields indicate that a node - * is in the process of being deleted or created. For purposes of - * read-only, access, a key may be read before a val, but can only - * be used after checking val. (For an update operation, when a - * lock is held on a node, order doesn't matter.) + * Key-value entry. This class is never exported out as a + * user-mutable Map.Entry (i.e., one supporting setValue; see + * MapEntry below), but can be used for read-only traversals used + * in bulk tasks. Subclasses of Node with a negative hash field + * are special, and contain null keys and values (but are never + * exported). Otherwise, keys and vals are never null. */ - static final class Node { + static class Node implements Map.Entry { final int hash; - final Object key; - volatile Object val; - volatile Node next; + final K key; + volatile V val; + volatile Node next; - Node(int hash, Object key, Object val, Node next) { + Node(int hash, K key, V val, Node next) { this.hash = hash; this.key = key; this.val = val; this.next = next; } - } - - /** - * Sign bit of node hash value indicating to use table in node.key. - */ - private static final int SIGN_BIT = 0x80000000; - - /* ---------------- Fields -------------- */ - - /** - * The array of bins. Lazily initialized upon first insertion. - * Size is always a power of two. Accessed directly by iterators. - */ - transient volatile Node[] table; - - /** The counter maintaining number of elements. */ - private transient final LongAdder counter; - /** Nonzero when table is being initialized or resized. Updated via CAS. */ - private transient volatile int resizing; - /** The next element count value upon which to resize the table. */ - private transient int threshold; - /** The target capacity; volatile to cover initialization races. */ - private transient volatile int targetCapacity; - - // views - private transient KeySet keySet; - private transient Values values; - private transient EntrySet entrySet; - /** For serialization compatibility. Null unless serialized; see below */ - private Segment[] segments; - - /* ---------------- Table element access -------------- */ + public final K getKey() { return key; } + public final V getValue() { return val; } + public final int hashCode() { return key.hashCode() ^ val.hashCode(); } + public final String toString(){ return key + "=" + val; } + public final V setValue(V value) { + throw new UnsupportedOperationException(); + } - /* - * Volatile access methods are used for table elements as well as - * elements of in-progress next table while resizing. Uses are - * null checked by callers, and implicitly bounds-checked, relying - * on the invariants that tab arrays have non-zero size, and all - * indices are masked with (tab.length - 1) which is never - * negative and always less than length. Note that, to be correct - * wrt arbitrary concurrency errors by users, bounds checks must - * operate on local variables, which accounts for some odd-looking - * inline assignments below. - */ + public final boolean equals(Object o) { + Object k, v, u; Map.Entry e; + return ((o instanceof Map.Entry) && + (k = (e = (Map.Entry)o).getKey()) != null && + (v = e.getValue()) != null && + (k == key || k.equals(key)) && + (v == (u = val) || v.equals(u))); + } - static final Node tabAt(Node[] tab, int i) { // used by InternalIterator - return (Node)UNSAFE.getObjectVolatile(tab, ((long)i< find(int h, Object k) { + Node e = this; + if (k != null) { + do { + K ek; + if (e.hash == h && + ((ek = e.key) == k || (ek != null && k.equals(ek)))) + return e; + } while ((e = e.next) != null); + } + return null; + } } - private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) { - return UNSAFE.compareAndSwapObject(tab, ((long)i<>> 16)) & HASH_BITS; } - /* ----------------Table Initialization and Resizing -------------- */ - /** * Returns a power of two table size for the given desired capacity. * See Hackers Delight, sec 3.2 @@ -382,480 +677,132 @@ public class ConcurrentHashMapV8 } /** - * If not already resizing, initializes or creates next table and - * transfers bins. Initial table size uses the capacity recorded - * in targetCapacity. Rechecks occupancy after a transfer to see - * if another resize is already needed because resizings are - * lagging additions. - * - * @return current table - */ - private final Node[] growTable() { - if (resizing == 0 && - UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { - try { - for (;;) { - Node[] tab = table; - int n, c, m; - if (tab == null) - n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY; - else if ((m = tab.length) < MAXIMUM_CAPACITY && - counter.sum() >= (long)threshold) - n = m << 1; - else - break; - threshold = n - (n >>> 2) - THRESHOLD_OFFSET; - Node[] nextTab = new Node[n]; - if (tab != null) - transfer(tab, nextTab, - new Node(SIGN_BIT, nextTab, null, null)); - table = nextTab; - if (tab == null) - break; + * Returns x's Class if it is of the form "class C implements + * Comparable", else null. + */ + static Class comparableClassFor(Object x) { + if (x instanceof Comparable) { + Class c; Type[] ts, as; Type t; ParameterizedType p; + if ((c = x.getClass()) == String.class) // bypass checks + return c; + if ((ts = c.getGenericInterfaces()) != null) { + for (int i = 0; i < ts.length; ++i) { + if (((t = ts[i]) instanceof ParameterizedType) && + ((p = (ParameterizedType)t).getRawType() == + Comparable.class) && + (as = p.getActualTypeArguments()) != null && + as.length == 1 && as[0] == c) // type arg is c + return c; } - } finally { - resizing = 0; } } - else if (table == null) - Thread.yield(); // lost initialization race; just spin - return table; + return null; } - /* - * Reclassifies nodes in each bin to new table. Because we are - * using power-of-two expansion, the elements from each bin must - * either stay at same index, or move with a power of two - * offset. We eliminate unnecessary node creation by catching - * cases where old nodes can be reused because their next fields - * won't change. Statistically, only about one-sixth of them need - * cloning when a table doubles. The nodes they replace will be - * garbage collectable as soon as they are no longer referenced by - * any reader thread that may be in the midst of concurrently - * traversing table. - * - * Transfers are done from the bottom up to preserve iterator - * traversability. On each step, the old bin is locked, - * moved/copied, and then replaced with a forwarding node. - */ - private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) { - int n = tab.length; - Node ignore = nextTab[n + n - 1]; // force bounds check - for (int i = n - 1; i >= 0; --i) { - for (Node e;;) { - if ((e = tabAt(tab, i)) != null) { - boolean validated = false; - synchronized (e) { - if (tabAt(tab, i) == e) { - validated = true; - Node lo = null, hi = null, lastRun = e; - int runBit = e.hash & n; - for (Node p = e.next; p != null; p = p.next) { - int b = p.hash & n; - if (b != runBit) { - runBit = b; - lastRun = p; - } - } - if (runBit == 0) - lo = lastRun; - else - hi = lastRun; - for (Node p = e; p != lastRun; p = p.next) { - int ph = p.hash; - Object pk = p.key, pv = p.val; - if ((ph & n) == 0) - lo = new Node(ph, pk, pv, lo); - else - hi = new Node(ph, pk, pv, hi); - } - setTabAt(nextTab, i, lo); - setTabAt(nextTab, i + n, hi); - setTabAt(tab, i, fwd); - } - } - if (validated) - break; - } - else if (casTabAt(tab, i, e, fwd)) - break; - } - } + /** + * Returns k.compareTo(x) if x matches kc (k's screened comparable + * class), else 0. + */ + @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable + static int compareComparables(Class kc, Object k, Object x) { + return (x == null || x.getClass() != kc ? 0 : + ((Comparable)k).compareTo(x)); } - /* ---------------- Internal access and update methods -------------- */ + /* ---------------- Table element access -------------- */ - /** - * Applies a supplemental hash function to a given hashCode, which - * defends against poor quality hash functions. The result must - * be non-negative, and for reasonable performance must have good - * avalanche properties; i.e., that each bit of the argument - * affects each bit (except sign bit) of the result. - */ - private static final int spread(int h) { - // Apply base step of MurmurHash; see http://code.google.com/p/smhasher/ - h ^= h >>> 16; - h *= 0x85ebca6b; - h ^= h >>> 13; - h *= 0xc2b2ae35; - return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit - } - - /** Implementation for get and containsKey */ - private final Object internalGet(Object k) { - int h = spread(k.hashCode()); - retry: for (Node[] tab = table; tab != null;) { - Node e; Object ek, ev; int eh; // locals to read fields once - for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) { - if ((eh = e.hash) == h) { - if ((ev = e.val) != null && - ((ek = e.key) == k || k.equals(ek))) - return ev; - } - else if (eh < 0) { // sign bit set - tab = (Node[])e.key; // bin was moved during resize - continue retry; - } - } - break; - } - return null; + /* + * Volatile access methods are used for table elements as well as + * elements of in-progress next table while resizing. All uses of + * the tab arguments must be null checked by callers. All callers + * also paranoically precheck that tab's length is not zero (or an + * equivalent check), thus ensuring that any index argument taking + * the form of a hash value anded with (length - 1) is a valid + * index. Note that, to be correct wrt arbitrary concurrency + * errors by users, these checks must operate on local variables, + * which accounts for some odd-looking inline assignments below. + * Note that calls to setTabAt always occur within locked regions, + * and so in principle require only release ordering, not need + * full volatile semantics, but are currently coded as volatile + * writes to be conservative. + */ + + @SuppressWarnings("unchecked") + static final Node tabAt(Node[] tab, int i) { + return (Node)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE); } - /** Implementation for put and putIfAbsent */ - private final Object internalPut(Object k, Object v, boolean replace) { - int h = spread(k.hashCode()); - Object oldVal = null; // previous value or null if none - for (Node[] tab = table;;) { - Node e; int i; Object ek, ev; - if (tab == null) - tab = growTable(); - else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) { - if (casTabAt(tab, i, null, new Node(h, k, v, null))) - break; // no lock when adding to empty bin - } - else if (e.hash < 0) // resized -- restart with new table - tab = (Node[])e.key; - else if (!replace && e.hash == h && (ev = e.val) != null && - ((ek = e.key) == k || k.equals(ek))) { - if (tabAt(tab, i) == e) { // inspect and validate 1st node - oldVal = ev; // without lock for putIfAbsent - break; - } - } - else { - boolean validated = false; - boolean checkSize = false; - synchronized (e) { // lock the 1st node of bin list - if (tabAt(tab, i) == e) { - validated = true; // retry if 1st already deleted - for (Node first = e;;) { - if (e.hash == h && - ((ek = e.key) == k || k.equals(ek)) && - (ev = e.val) != null) { - oldVal = ev; - if (replace) - e.val = v; - break; - } - Node last = e; - if ((e = e.next) == null) { - last.next = new Node(h, k, v, null); - if (last != first || tab.length <= 64) - checkSize = true; - break; - } - } - } - } - if (validated) { - if (checkSize && tab.length < MAXIMUM_CAPACITY && - resizing == 0 && counter.sum() >= (long)threshold) - growTable(); - break; - } - } - } - if (oldVal == null) - counter.increment(); // update counter outside of locks - return oldVal; + static final boolean casTabAt(Node[] tab, int i, + Node c, Node v) { + return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v); } + static final void setTabAt(Node[] tab, int i, Node v) { + U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v); + } + + /* ---------------- Fields -------------- */ + /** - * Implementation for the four public remove/replace methods: - * Replaces node value with v, conditional upon match of cv if - * non-null. If resulting value is null, delete. + * The array of bins. Lazily initialized upon first insertion. + * Size is always a power of two. Accessed directly by iterators. */ - private final Object internalReplace(Object k, Object v, Object cv) { - int h = spread(k.hashCode()); - for (Node[] tab = table;;) { - Node e; int i; - if (tab == null || - (e = tabAt(tab, i = (tab.length - 1) & h)) == null) - return null; - else if (e.hash < 0) - tab = (Node[])e.key; - else { - Object oldVal = null; - boolean validated = false; - boolean deleted = false; - synchronized (e) { - if (tabAt(tab, i) == e) { - validated = true; - Node pred = null; - do { - Object ek, ev; - if (e.hash == h && - ((ek = e.key) == k || k.equals(ek)) && - ((ev = e.val) != null)) { - if (cv == null || cv == ev || cv.equals(ev)) { - oldVal = ev; - if ((e.val = v) == null) { - deleted = true; - Node en = e.next; - if (pred != null) - pred.next = en; - else - setTabAt(tab, i, en); - } - } - break; - } - } while ((e = (pred = e).next) != null); - } - } - if (validated) { - if (deleted) - counter.decrement(); - return oldVal; - } - } - } - } + transient volatile Node[] table; - /** Implementation for computeIfAbsent and compute. Like put, but messier. */ - @SuppressWarnings("unchecked") - private final V internalCompute(K k, - MappingFunction f, - boolean replace) { - int h = spread(k.hashCode()); - V val = null; - boolean added = false; - Node[] tab = table; - outer:for (;;) { - Node e; int i; Object ek, ev; - if (tab == null) - tab = growTable(); - else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) { - Node node = new Node(h, k, null, null); - boolean validated = false; - synchronized (node) { // must lock while computing value - if (casTabAt(tab, i, null, node)) { - validated = true; - try { - val = f.map(k); - if (val != null) { - node.val = val; - added = true; - } - } finally { - if (!added) - setTabAt(tab, i, null); - } - } - } - if (validated) - break; - } - else if (e.hash < 0) - tab = (Node[])e.key; - else if (!replace && e.hash == h && (ev = e.val) != null && - ((ek = e.key) == k || k.equals(ek))) { - if (tabAt(tab, i) == e) { - val = (V)ev; - break; - } - } - else if (Thread.holdsLock(e)) - throw new IllegalStateException("Recursive map computation"); - else { - boolean validated = false; - boolean checkSize = false; - synchronized (e) { - if (tabAt(tab, i) == e) { - validated = true; - for (Node first = e;;) { - if (e.hash == h && - ((ek = e.key) == k || k.equals(ek)) && - ((ev = e.val) != null)) { - Object fv; - if (replace && (fv = f.map(k)) != null) - ev = e.val = fv; - val = (V)ev; - break; - } - Node last = e; - if ((e = e.next) == null) { - if ((val = f.map(k)) != null) { - last.next = new Node(h, k, val, null); - added = true; - if (last != first || tab.length <= 64) - checkSize = true; - } - break; - } - } - } - } - if (validated) { - if (checkSize && tab.length < MAXIMUM_CAPACITY && - resizing == 0 && counter.sum() >= (long)threshold) - growTable(); - break; - } - } - } - if (added) - counter.increment(); - return val; - } + /** + * The next table to use; non-null only while resizing. + */ + private transient volatile Node[] nextTable; /** - * Implementation for clear. Steps through each bin, removing all nodes. + * Base counter value, used mainly when there is no contention, + * but also as a fallback during table initialization + * races. Updated via CAS. */ - private final void internalClear() { - long delta = 0L; // negative number of deletions - int i = 0; - Node[] tab = table; - while (tab != null && i < tab.length) { - Node e = tabAt(tab, i); - if (e == null) - ++i; - else if (e.hash < 0) - tab = (Node[])e.key; - else { - boolean validated = false; - synchronized (e) { - if (tabAt(tab, i) == e) { - validated = true; - Node en; - do { - en = e.next; - if (e.val != null) { // currently always true - e.val = null; - --delta; - } - } while ((e = en) != null); - setTabAt(tab, i, null); - } - } - if (validated) - ++i; - } - } - counter.add(delta); - } + private transient volatile long baseCount; - /* ----------------Table Traversal -------------- */ + /** + * Table initialization and resizing control. When negative, the + * table is being initialized or resized: -1 for initialization, + * else -(1 + the number of active resizing threads). Otherwise, + * when table is null, holds the initial table size to use upon + * creation, or 0 for default. After initialization, holds the + * next element count value upon which to resize the table. + */ + private transient volatile int sizeCtl; /** - * Encapsulates traversal for methods such as containsValue; also - * serves as a base class for other iterators. - * - * At each step, the iterator snapshots the key ("nextKey") and - * value ("nextVal") of a valid node (i.e., one that, at point of - * snapshot, has a nonnull user value). Because val fields can - * change (including to null, indicating deletion), field nextVal - * might not be accurate at point of use, but still maintains the - * weak consistency property of holding a value that was once - * valid. - * - * Internal traversals directly access these fields, as in: - * {@code while (it.next != null) { process(nextKey); it.advance(); }} - * - * Exported iterators (subclasses of ViewIterator) extract key, - * value, or key-value pairs as return values of Iterator.next(), - * and encapulate the it.next check as hasNext(); - * - * The iterator visits each valid node that was reachable upon - * iterator construction once. It might miss some that were added - * to a bin after the bin was visited, which is OK wrt consistency - * guarantees. Maintaining this property in the face of possible - * ongoing resizes requires a fair amount of bookkeeping state - * that is difficult to optimize away amidst volatile accesses. - * Even so, traversal maintains reasonable throughput. - * - * Normally, iteration proceeds bin-by-bin traversing lists. - * However, if the table has been resized, then all future steps - * must traverse both the bin at the current index as well as at - * (index + baseSize); and so on for further resizings. To - * paranoically cope with potential sharing by users of iterators - * across threads, iteration terminates if a bounds checks fails - * for a table read. - * - * The range-based constructor enables creation of parallel - * range-splitting traversals. (Not yet implemented.) + * The next table index (plus one) to split while resizing. */ - static class InternalIterator { - Node next; // the next entry to use - Node last; // the last entry used - Object nextKey; // cached key field of next - Object nextVal; // cached val field of next - Node[] tab; // current table; updated if resized - int index; // index of bin to use next - int baseIndex; // current index of initial table - final int baseLimit; // index bound for initial table - final int baseSize; // initial table size + private transient volatile int transferIndex; - /** Creates iterator for all entries in the table. */ - InternalIterator(Node[] tab) { - this.tab = tab; - baseLimit = baseSize = (tab == null) ? 0 : tab.length; - index = baseIndex = 0; - next = null; - advance(); - } + /** + * The least available table index to split while resizing. + */ + private transient volatile int transferOrigin; - /** Creates iterator for the given range of the table */ - InternalIterator(Node[] tab, int lo, int hi) { - this.tab = tab; - baseSize = (tab == null) ? 0 : tab.length; - baseLimit = (hi <= baseSize) ? hi : baseSize; - index = baseIndex = lo; - next = null; - advance(); - } + /** + * Spinlock (locked via CAS) used when resizing and/or creating CounterCells. + */ + private transient volatile int cellsBusy; + + /** + * Table of counter cells. When non-null, size is a power of 2. + */ + private transient volatile CounterCell[] counterCells; + + // views + private transient KeySetView keySet; + private transient ValuesView values; + private transient EntrySetView entrySet; - /** Advances next. See above for explanation. */ - final void advance() { - Node e = last = next; - outer: do { - if (e != null) // pass used or skipped node - e = e.next; - while (e == null) { // get to next non-null bin - Node[] t; int b, i, n; // checks must use locals - if ((b = baseIndex) >= baseLimit || (i = index) < 0 || - (t = tab) == null || i >= (n = t.length)) - break outer; - else if ((e = tabAt(t, i)) != null && e.hash < 0) - tab = (Node[])e.key; // restarts due to null val - else // visit upper slots if present - index = (i += baseSize) < n ? i : (baseIndex = b + 1); - } - nextKey = e.key; - } while ((nextVal = e.val) == null); // skip deleted or special nodes - next = e; - } - } /* ---------------- Public operations -------------- */ /** - * Creates a new, empty map with the default initial table size (16), + * Creates a new, empty map with the default initial table size (16). */ public ConcurrentHashMapV8() { - this.counter = new LongAdder(); - this.targetCapacity = DEFAULT_CAPACITY; } /** @@ -866,7 +813,7 @@ public class ConcurrentHashMapV8 * @param initialCapacity The implementation performs internal * sizing to accommodate this many elements. * @throws IllegalArgumentException if the initial capacity of - * elements is negative. + * elements is negative */ public ConcurrentHashMapV8(int initialCapacity) { if (initialCapacity < 0) @@ -874,8 +821,7 @@ public class ConcurrentHashMapV8 int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); - this.counter = new LongAdder(); - this.targetCapacity = cap; + this.sizeCtl = cap; } /** @@ -884,8 +830,7 @@ public class ConcurrentHashMapV8 * @param m the map */ public ConcurrentHashMapV8(Map m) { - this.counter = new LongAdder(); - this.targetCapacity = DEFAULT_CAPACITY; + this.sizeCtl = DEFAULT_CAPACITY; putAll(m); } @@ -898,7 +843,7 @@ public class ConcurrentHashMapV8 * performs internal sizing to accommodate this many elements, * given the specified load factor. * @param loadFactor the load factor (table density) for - * establishing the initial table size. + * establishing the initial table size * @throws IllegalArgumentException if the initial capacity of * elements is negative or the load factor is nonpositive * @@ -918,45 +863,46 @@ public class ConcurrentHashMapV8 * performs internal sizing to accommodate this many elements, * given the specified load factor. * @param loadFactor the load factor (table density) for - * establishing the initial table size. + * establishing the initial table size * @param concurrencyLevel the estimated number of concurrently * updating threads. The implementation may use this value as * a sizing hint. * @throws IllegalArgumentException if the initial capacity is * negative or the load factor or concurrencyLevel are - * nonpositive. + * nonpositive */ public ConcurrentHashMapV8(int initialCapacity, - float loadFactor, int concurrencyLevel) { + float loadFactor, int concurrencyLevel) { if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) throw new IllegalArgumentException(); if (initialCapacity < concurrencyLevel) // Use at least as many bins initialCapacity = concurrencyLevel; // as estimated threads long size = (long)(1.0 + (long)initialCapacity / loadFactor); - int cap = ((size >= (long)MAXIMUM_CAPACITY) ? - MAXIMUM_CAPACITY: tableSizeFor((int)size)); - this.counter = new LongAdder(); - this.targetCapacity = cap; + int cap = (size >= (long)MAXIMUM_CAPACITY) ? + MAXIMUM_CAPACITY : tableSizeFor((int)size); + this.sizeCtl = cap; } - /** - * {@inheritDoc} - */ - public boolean isEmpty() { - return counter.sum() <= 0L; // ignore transient negative values - } + // Original (since JDK1.2) Map methods /** * {@inheritDoc} */ public int size() { - long n = counter.sum(); + long n = sumCount(); return ((n < 0L) ? 0 : (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int)n); } /** + * {@inheritDoc} + */ + public boolean isEmpty() { + return sumCount() <= 0L; // ignore transient negative values + } + + /** * Returns the value to which the specified key is mapped, * or {@code null} if this map contains no mapping for the key. * @@ -967,26 +913,37 @@ public class ConcurrentHashMapV8 * * @throws NullPointerException if the specified key is null */ - @SuppressWarnings("unchecked") public V get(Object key) { - if (key == null) - throw new NullPointerException(); - return (V)internalGet(key); + Node[] tab; Node e, p; int n, eh; K ek; + int h = spread(key.hashCode()); + if ((tab = table) != null && (n = tab.length) > 0 && + (e = tabAt(tab, (n - 1) & h)) != null) { + if ((eh = e.hash) == h) { + if ((ek = e.key) == key || (ek != null && key.equals(ek))) + return e.val; + } + else if (eh < 0) + return (p = e.find(h, key)) != null ? p.val : null; + while ((e = e.next) != null) { + if (e.hash == h && + ((ek = e.key) == key || (ek != null && key.equals(ek)))) + return e.val; + } + } + return null; } /** * Tests if the specified object is a key in this table. * - * @param key possible key + * @param key possible key * @return {@code true} if and only if the specified object * is a key in this table, as determined by the - * {@code equals} method; {@code false} otherwise. + * {@code equals} method; {@code false} otherwise * @throws NullPointerException if the specified key is null */ public boolean containsKey(Object key) { - if (key == null) - throw new NullPointerException(); - return internalGet(key) != null; + return get(key) != null; } /** @@ -1002,40 +959,23 @@ public class ConcurrentHashMapV8 public boolean containsValue(Object value) { if (value == null) throw new NullPointerException(); - Object v; - InternalIterator it = new InternalIterator(table); - while (it.next != null) { - if ((v = it.nextVal) == value || value.equals(v)) - return true; - it.advance(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + V v; + if ((v = p.val) == value || (v != null && value.equals(v))) + return true; + } } return false; } /** - * Legacy method testing if some key maps into the specified value - * in this table. This method is identical in functionality to - * {@link #containsValue}, and exists solely to ensure - * full compatibility with class {@link java.util.Hashtable}, - * which supported this method prior to introduction of the - * Java Collections framework. - * - * @param value a value to search for - * @return {@code true} if and only if some key maps to the - * {@code value} argument in this table as - * determined by the {@code equals} method; - * {@code false} otherwise - * @throws NullPointerException if the specified value is null - */ - public boolean contains(Object value) { - return containsValue(value); - } - - /** * Maps the specified key to the specified value in this table. * Neither the key nor the value can be null. * - *

The value can be retrieved by calling the {@code get} method + *

The value can be retrieved by calling the {@code get} method * with a key that is equal to the original key. * * @param key key with which the specified value is to be associated @@ -1044,25 +984,73 @@ public class ConcurrentHashMapV8 * {@code null} if there was no mapping for {@code key} * @throws NullPointerException if the specified key or value is null */ - @SuppressWarnings("unchecked") public V put(K key, V value) { - if (key == null || value == null) - throw new NullPointerException(); - return (V)internalPut(key, value, true); + return putVal(key, value, false); } - /** - * {@inheritDoc} - * - * @return the previous value associated with the specified key, - * or {@code null} if there was no mapping for the key - * @throws NullPointerException if the specified key or value is null - */ - @SuppressWarnings("unchecked") - public V putIfAbsent(K key, V value) { - if (key == null || value == null) - throw new NullPointerException(); - return (V)internalPut(key, value, false); + /** Implementation for put and putIfAbsent */ + final V putVal(K key, V value, boolean onlyIfAbsent) { + if (key == null || value == null) throw new NullPointerException(); + int hash = spread(key.hashCode()); + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) { + if (casTabAt(tab, i, null, + new Node(hash, key, value, null))) + break; // no lock when adding to empty bin + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + V oldVal = null; + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f;; ++binCount) { + K ek; + if (e.hash == hash && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + oldVal = e.val; + if (!onlyIfAbsent) + e.val = value; + break; + } + Node pred = e; + if ((e = e.next) == null) { + pred.next = new Node(hash, key, + value, null); + break; + } + } + } + else if (f instanceof TreeBin) { + Node p; + binCount = 2; + if ((p = ((TreeBin)f).putTreeVal(hash, key, + value)) != null) { + oldVal = p.val; + if (!onlyIfAbsent) + p.val = value; + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + if (oldVal != null) + return oldVal; + break; + } + } + } + addCount(1L, binCount); + return null; } /** @@ -1073,100 +1061,9 @@ public class ConcurrentHashMapV8 * @param m mappings to be stored in this map */ public void putAll(Map m) { - if (m == null) - throw new NullPointerException(); - /* - * If uninitialized, try to adjust targetCapacity to - * accommodate the given number of elements. - */ - if (table == null) { - int size = m.size(); - int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : - tableSizeFor(size + (size >>> 1) + 1); - if (cap > targetCapacity) - targetCapacity = cap; - } + tryPresize(m.size()); for (Map.Entry e : m.entrySet()) - put(e.getKey(), e.getValue()); - } - - /** - * If the specified key is not already associated with a value, - * computes its value using the given mappingFunction, and if - * non-null, enters it into the map. This is equivalent to - * 

 {@code
-     * if (map.containsKey(key))
-     *   return map.get(key);
-     * value = mappingFunction.map(key);
-     * if (value != null)
-     *   map.put(key, value);
-     * return value;}
- * - * except that the action is performed atomically. Some attempted - * update operations on this map by other threads may be blocked - * while computation is in progress, so the computation should be - * short and simple, and must not attempt to update any other - * mappings of this Map. The most appropriate usage is to - * construct a new object serving as an initial mapped value, or - * memoized result, as in: - * 
 {@code
-     * map.computeIfAbsent(key, new MappingFunction() {
-     *   public V map(K k) { return new Value(f(k)); }});}
- * - * @param key key with which the specified value is to be associated - * @param mappingFunction the function to compute a value - * @return the current (existing or computed) value associated with - * the specified key, or {@code null} if the computation - * returned {@code null}. - * @throws NullPointerException if the specified key or mappingFunction - * is null, - * @throws IllegalStateException if the computation detectably - * attempts a recursive update to this map that would - * otherwise never complete. - * @throws RuntimeException or Error if the mappingFunction does so, - * in which case the mapping is left unestablished. - */ - public V computeIfAbsent(K key, MappingFunction mappingFunction) { - if (key == null || mappingFunction == null) - throw new NullPointerException(); - return internalCompute(key, mappingFunction, false); - } - - /** - * Computes the value associated with the given key using the given - * mappingFunction, and if non-null, enters it into the map. This - * is equivalent to - * 
 {@code
-     * value = mappingFunction.map(key);
-     * if (value != null)
-     *   map.put(key, value);
-     * else
-     *   value = map.get(key);
-     * return value;}
- * - * except that the action is performed atomically. Some attempted - * update operations on this map by other threads may be blocked - * while computation is in progress, so the computation should be - * short and simple, and must not attempt to update any other - * mappings of this Map. - * - * @param key key with which the specified value is to be associated - * @param mappingFunction the function to compute a value - * @return the current value associated with - * the specified key, or {@code null} if the computation - * returned {@code null} and the value was not otherwise present. - * @throws NullPointerException if the specified key or mappingFunction - * is null, - * @throws IllegalStateException if the computation detectably - * attempts a recursive update to this map that would - * otherwise never complete. - * @throws RuntimeException or Error if the mappingFunction does so, - * in which case the mapping is unchanged. - */ - public V compute(K key, MappingFunction mappingFunction) { - if (key == null || mappingFunction == null) - throw new NullPointerException(); - return internalCompute(key, mappingFunction, true); + putVal(e.getKey(), e.getValue(), false); } /** @@ -1178,62 +1075,125 @@ public class ConcurrentHashMapV8 * {@code null} if there was no mapping for {@code key} * @throws NullPointerException if the specified key is null */ - @SuppressWarnings("unchecked") public V remove(Object key) { - if (key == null) - throw new NullPointerException(); - return (V)internalReplace(key, null, null); - } - - /** - * {@inheritDoc} - * - * @throws NullPointerException if the specified key is null - */ - public boolean remove(Object key, Object value) { - if (key == null) - throw new NullPointerException(); - if (value == null) - return false; - return internalReplace(key, null, value) != null; - } - - /** - * {@inheritDoc} - * - * @throws NullPointerException if any of the arguments are null - */ - public boolean replace(K key, V oldValue, V newValue) { - if (key == null || oldValue == null || newValue == null) - throw new NullPointerException(); - return internalReplace(key, newValue, oldValue) != null; + return replaceNode(key, null, null); } /** - * {@inheritDoc} - * - * @return the previous value associated with the specified key, - * or {@code null} if there was no mapping for the key - * @throws NullPointerException if the specified key or value is null + * Implementation for the four public remove/replace methods: + * Replaces node value with v, conditional upon match of cv if + * non-null. If resulting value is null, delete. */ - @SuppressWarnings("unchecked") - public V replace(K key, V value) { - if (key == null || value == null) - throw new NullPointerException(); - return (V)internalReplace(key, value, null); + final V replaceNode(Object key, V value, Object cv) { + int hash = spread(key.hashCode()); + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0 || + (f = tabAt(tab, i = (n - 1) & hash)) == null) + break; + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + V oldVal = null; + boolean validated = false; + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + validated = true; + for (Node e = f, pred = null;;) { + K ek; + if (e.hash == hash && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + V ev = e.val; + if (cv == null || cv == ev || + (ev != null && cv.equals(ev))) { + oldVal = ev; + if (value != null) + e.val = value; + else if (pred != null) + pred.next = e.next; + else + setTabAt(tab, i, e.next); + } + break; + } + pred = e; + if ((e = e.next) == null) + break; + } + } + else if (f instanceof TreeBin) { + validated = true; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null && + (p = r.findTreeNode(hash, key, null)) != null) { + V pv = p.val; + if (cv == null || cv == pv || + (pv != null && cv.equals(pv))) { + oldVal = pv; + if (value != null) + p.val = value; + else if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + } + if (validated) { + if (oldVal != null) { + if (value == null) + addCount(-1L, -1); + return oldVal; + } + break; + } + } + } + return null; } /** * Removes all of the mappings from this map. */ public void clear() { - internalClear(); + long delta = 0L; // negative number of deletions + int i = 0; + Node[] tab = table; + while (tab != null && i < tab.length) { + int fh; + Node f = tabAt(tab, i); + if (f == null) + ++i; + else if ((fh = f.hash) == MOVED) { + tab = helpTransfer(tab, f); + i = 0; // restart + } + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + Node p = (fh >= 0 ? f : + (f instanceof TreeBin) ? + ((TreeBin)f).first : null); + while (p != null) { + --delta; + p = p.next; + } + setTabAt(tab, i++, null); + } + } + } + } + if (delta != 0L) + addCount(delta, -1); } /** * Returns a {@link Set} view of the keys contained in this map. * The set is backed by the map, so changes to the map are - * reflected in the set, and vice-versa. The set supports element + * reflected in the set, and vice-versa. The set supports element * removal, which removes the corresponding mapping from this map, * via the {@code Iterator.remove}, {@code Set.remove}, * {@code removeAll}, {@code retainAll}, and {@code clear} @@ -1245,10 +1205,12 @@ public class ConcurrentHashMapV8 * and guarantees to traverse elements as they existed upon * construction of the iterator, and may (but is not guaranteed to) * reflect any modifications subsequent to construction. + * + * @return the set view */ - public Set keySet() { - KeySet ks = keySet; - return (ks != null) ? ks : (keySet = new KeySet(this)); + public KeySetView keySet() { + KeySetView ks; + return (ks = keySet) != null ? ks : (keySet = new KeySetView(this, null)); } /** @@ -1266,10 +1228,12 @@ public class ConcurrentHashMapV8 * and guarantees to traverse elements as they existed upon * construction of the iterator, and may (but is not guaranteed to) * reflect any modifications subsequent to construction. + * + * @return the collection view */ public Collection values() { - Values vs = values; - return (vs != null) ? vs : (values = new Values(this)); + ValuesView vs; + return (vs = values) != null ? vs : (values = new ValuesView(this)); } /** @@ -1279,38 +1243,19 @@ public class ConcurrentHashMapV8 * removal, which removes the corresponding mapping from the map, * via the {@code Iterator.remove}, {@code Set.remove}, * {@code removeAll}, {@code retainAll}, and {@code clear} - * operations. It does not support the {@code add} or - * {@code addAll} operations. + * operations. * *

The view's {@code iterator} is a "weakly consistent" iterator * that will never throw {@link ConcurrentModificationException}, * and guarantees to traverse elements as they existed upon * construction of the iterator, and may (but is not guaranteed to) * reflect any modifications subsequent to construction. - */ - public Set> entrySet() { - EntrySet es = entrySet; - return (es != null) ? es : (entrySet = new EntrySet(this)); - } - - /** - * Returns an enumeration of the keys in this table. * - * @return an enumeration of the keys in this table - * @see #keySet() + * @return the set view */ - public Enumeration keys() { - return new KeyIterator(this); - } - - /** - * Returns an enumeration of the values in this table. - * - * @return an enumeration of the values in this table - * @see #values() - */ - public Enumeration elements() { - return new ValueIterator(this); + public Set> entrySet() { + EntrySetView es; + return (es = entrySet) != null ? es : (entrySet = new EntrySetView(this)); } /** @@ -1322,10 +1267,11 @@ public class ConcurrentHashMapV8 */ public int hashCode() { int h = 0; - InternalIterator it = new InternalIterator(table); - while (it.next != null) { - h += it.nextKey.hashCode() ^ it.nextVal.hashCode(); - it.advance(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + h += p.key.hashCode() ^ p.val.hashCode(); } return h; } @@ -1342,17 +1288,20 @@ public class ConcurrentHashMapV8 * @return a string representation of this map */ public String toString() { - InternalIterator it = new InternalIterator(table); + Node[] t; + int f = (t = table) == null ? 0 : t.length; + Traverser it = new Traverser(t, f, 0, f); StringBuilder sb = new StringBuilder(); sb.append('{'); - if (it.next != null) { + Node p; + if ((p = it.advance()) != null) { for (;;) { - Object k = it.nextKey, v = it.nextVal; + K k = p.key; + V v = p.val; sb.append(k == this ? "(this Map)" : k); sb.append('='); sb.append(v == this ? "(this Map)" : v); - it.advance(); - if (it.next == null) + if ((p = it.advance()) == null) break; sb.append(',').append(' '); } @@ -1375,19 +1324,20 @@ public class ConcurrentHashMapV8 if (!(o instanceof Map)) return false; Map m = (Map) o; - InternalIterator it = new InternalIterator(table); - while (it.next != null) { - Object val = it.nextVal; - Object v = m.get(it.nextKey); + Node[] t; + int f = (t = table) == null ? 0 : t.length; + Traverser it = new Traverser(t, f, 0, f); + for (Node p; (p = it.advance()) != null; ) { + V val = p.val; + Object v = m.get(p.key); if (v == null || (v != val && !v.equals(val))) return false; - it.advance(); } for (Map.Entry e : m.entrySet()) { Object mk, mv, v; if ((mk = e.getKey()) == null || (mv = e.getValue()) == null || - (v = internalGet(mk)) == null || + (v = get(mk)) == null || (mv != v && !mv.equals(v))) return false; } @@ -1395,95 +1345,1926 @@ public class ConcurrentHashMapV8 return true; } - /* ----------------Iterators -------------- */ + /** + * Stripped-down version of helper class used in previous version, + * declared for the sake of serialization compatibility + */ + static class Segment extends ReentrantLock implements Serializable { + private static final long serialVersionUID = 2249069246763182397L; + final float loadFactor; + Segment(float lf) { this.loadFactor = lf; } + } + + /** + * Saves the state of the {@code ConcurrentHashMapV8} instance to a + * stream (i.e., serializes it). + * @param s the stream + * @serialData + * the key (Object) and value (Object) + * for each key-value mapping, followed by a null pair. + * The key-value mappings are emitted in no particular order. + */ + private void writeObject(java.io.ObjectOutputStream s) + throws java.io.IOException { + // For serialization compatibility + // Emulate segment calculation from previous version of this class + int sshift = 0; + int ssize = 1; + while (ssize < DEFAULT_CONCURRENCY_LEVEL) { + ++sshift; + ssize <<= 1; + } + int segmentShift = 32 - sshift; + int segmentMask = ssize - 1; + @SuppressWarnings("unchecked") Segment[] segments = (Segment[]) + new Segment[DEFAULT_CONCURRENCY_LEVEL]; + for (int i = 0; i < segments.length; ++i) + segments[i] = new Segment(LOAD_FACTOR); + s.putFields().put("segments", segments); + s.putFields().put("segmentShift", segmentShift); + s.putFields().put("segmentMask", segmentMask); + s.writeFields(); + + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + s.writeObject(p.key); + s.writeObject(p.val); + } + } + s.writeObject(null); + s.writeObject(null); + segments = null; // throw away + } + + /** + * Reconstitutes the instance from a stream (that is, deserializes it). + * @param s the stream + */ + private void readObject(java.io.ObjectInputStream s) + throws java.io.IOException, ClassNotFoundException { + /* + * To improve performance in typical cases, we create nodes + * while reading, then place in table once size is known. + * However, we must also validate uniqueness and deal with + * overpopulated bins while doing so, which requires + * specialized versions of putVal mechanics. + */ + sizeCtl = -1; // force exclusion for table construction + s.defaultReadObject(); + long size = 0L; + Node p = null; + for (;;) { + @SuppressWarnings("unchecked") K k = (K) s.readObject(); + @SuppressWarnings("unchecked") V v = (V) s.readObject(); + if (k != null && v != null) { + p = new Node(spread(k.hashCode()), k, v, p); + ++size; + } + else + break; + } + if (size == 0L) + sizeCtl = 0; + else { + int n; + if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) + n = MAXIMUM_CAPACITY; + else { + int sz = (int)size; + n = tableSizeFor(sz + (sz >>> 1) + 1); + } + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] tab = (Node[])new Node[n]; + int mask = n - 1; + long added = 0L; + while (p != null) { + boolean insertAtFront; + Node next = p.next, first; + int h = p.hash, j = h & mask; + if ((first = tabAt(tab, j)) == null) + insertAtFront = true; + else { + K k = p.key; + if (first.hash < 0) { + TreeBin t = (TreeBin)first; + if (t.putTreeVal(h, k, p.val) == null) + ++added; + insertAtFront = false; + } + else { + int binCount = 0; + insertAtFront = true; + Node q; K qk; + for (q = first; q != null; q = q.next) { + if (q.hash == h && + ((qk = q.key) == k || + (qk != null && k.equals(qk)))) { + insertAtFront = false; + break; + } + ++binCount; + } + if (insertAtFront && binCount >= TREEIFY_THRESHOLD) { + insertAtFront = false; + ++added; + p.next = first; + TreeNode hd = null, tl = null; + for (q = p; q != null; q = q.next) { + TreeNode t = new TreeNode + (q.hash, q.key, q.val, null, null); + if ((t.prev = tl) == null) + hd = t; + else + tl.next = t; + tl = t; + } + setTabAt(tab, j, new TreeBin(hd)); + } + } + } + if (insertAtFront) { + ++added; + p.next = first; + setTabAt(tab, j, p); + } + p = next; + } + table = tab; + sizeCtl = n - (n >>> 2); + baseCount = added; + } + } + + // ConcurrentMap methods + + /** + * {@inheritDoc} + * + * @return the previous value associated with the specified key, + * or {@code null} if there was no mapping for the key + * @throws NullPointerException if the specified key or value is null + */ + public V putIfAbsent(K key, V value) { + return putVal(key, value, true); + } + + /** + * {@inheritDoc} + * + * @throws NullPointerException if the specified key is null + */ + public boolean remove(Object key, Object value) { + if (key == null) + throw new NullPointerException(); + return value != null && replaceNode(key, null, value) != null; + } + + /** + * {@inheritDoc} + * + * @throws NullPointerException if any of the arguments are null + */ + public boolean replace(K key, V oldValue, V newValue) { + if (key == null || oldValue == null || newValue == null) + throw new NullPointerException(); + return replaceNode(key, newValue, oldValue) != null; + } + + /** + * {@inheritDoc} + * + * @return the previous value associated with the specified key, + * or {@code null} if there was no mapping for the key + * @throws NullPointerException if the specified key or value is null + */ + public V replace(K key, V value) { + if (key == null || value == null) + throw new NullPointerException(); + return replaceNode(key, value, null); + } + + // Overrides of JDK8+ Map extension method defaults + + /** + * Returns the value to which the specified key is mapped, or the + * given default value if this map contains no mapping for the + * key. + * + * @param key the key whose associated value is to be returned + * @param defaultValue the value to return if this map contains + * no mapping for the given key + * @return the mapping for the key, if present; else the default value + * @throws NullPointerException if the specified key is null + */ + public V getOrDefault(Object key, V defaultValue) { + V v; + return (v = get(key)) == null ? defaultValue : v; + } + + public void forEach(BiAction action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + action.apply(p.key, p.val); + } + } + } + + public void replaceAll(BiFun function) { + if (function == null) throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + V oldValue = p.val; + for (K key = p.key;;) { + V newValue = function.apply(key, oldValue); + if (newValue == null) + throw new NullPointerException(); + if (replaceNode(key, newValue, oldValue) != null || + (oldValue = get(key)) == null) + break; + } + } + } + } + + /** + * If the specified key is not already associated with a value, + * attempts to compute its value using the given mapping function + * and enters it into this map unless {@code null}. The entire + * method invocation is performed atomically, so the function is + * applied at most once per key. Some attempted update operations + * on this map by other threads may be blocked while computation + * is in progress, so the computation should be short and simple, + * and must not attempt to update any other mappings of this map. + * + * @param key key with which the specified value is to be associated + * @param mappingFunction the function to compute a value + * @return the current (existing or computed) value associated with + * the specified key, or null if the computed value is null + * @throws NullPointerException if the specified key or mappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the mappingFunction does so, + * in which case the mapping is left unestablished + */ + public V computeIfAbsent(K key, Fun mappingFunction) { + if (key == null || mappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { + Node r = new ReservationNode(); + synchronized (r) { + if (casTabAt(tab, i, null, r)) { + binCount = 1; + Node node = null; + try { + if ((val = mappingFunction.apply(key)) != null) + node = new Node(h, key, val, null); + } finally { + setTabAt(tab, i, node); + } + } + } + if (binCount != 0) + break; + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + boolean added = false; + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f;; ++binCount) { + K ek; V ev; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = e.val; + break; + } + Node pred = e; + if ((e = e.next) == null) { + if ((val = mappingFunction.apply(key)) != null) { + added = true; + pred.next = new Node(h, key, val, null); + } + break; + } + } + } + else if (f instanceof TreeBin) { + binCount = 2; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null && + (p = r.findTreeNode(h, key, null)) != null) + val = p.val; + else if ((val = mappingFunction.apply(key)) != null) { + added = true; + t.putTreeVal(h, key, val); + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + if (!added) + return val; + break; + } + } + } + if (val != null) + addCount(1L, binCount); + return val; + } + + /** + * If the value for the specified key is present, attempts to + * compute a new mapping given the key and its current mapped + * value. The entire method invocation is performed atomically. + * Some attempted update operations on this map by other threads + * may be blocked while computation is in progress, so the + * computation should be short and simple, and must not attempt to + * update any other mappings of this map. + * + * @param key key with which a value may be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or remappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V computeIfPresent(K key, BiFun remappingFunction) { + if (key == null || remappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int delta = 0; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) + break; + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f, pred = null;; ++binCount) { + K ek; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = remappingFunction.apply(key, e.val); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) + break; + } + } + else if (f instanceof TreeBin) { + binCount = 2; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null && + (p = r.findTreeNode(h, key, null)) != null) { + val = remappingFunction.apply(key, p.val); + if (val != null) + p.val = val; + else { + delta = -1; + if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + } + if (binCount != 0) + break; + } + } + if (delta != 0) + addCount((long)delta, binCount); + return val; + } + + /** + * Attempts to compute a mapping for the specified key and its + * current mapped value (or {@code null} if there is no current + * mapping). The entire method invocation is performed atomically. + * Some attempted update operations on this map by other threads + * may be blocked while computation is in progress, so the + * computation should be short and simple, and must not attempt to + * update any other mappings of this Map. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or remappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V compute(K key, + BiFun remappingFunction) { + if (key == null || remappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int delta = 0; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { + Node r = new ReservationNode(); + synchronized (r) { + if (casTabAt(tab, i, null, r)) { + binCount = 1; + Node node = null; + try { + if ((val = remappingFunction.apply(key, null)) != null) { + delta = 1; + node = new Node(h, key, val, null); + } + } finally { + setTabAt(tab, i, node); + } + } + } + if (binCount != 0) + break; + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f, pred = null;; ++binCount) { + K ek; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = remappingFunction.apply(key, e.val); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) { + val = remappingFunction.apply(key, null); + if (val != null) { + delta = 1; + pred.next = + new Node(h, key, val, null); + } + break; + } + } + } + else if (f instanceof TreeBin) { + binCount = 1; + TreeBin t = (TreeBin)f; + TreeNode r, p; + if ((r = t.root) != null) + p = r.findTreeNode(h, key, null); + else + p = null; + V pv = (p == null) ? null : p.val; + val = remappingFunction.apply(key, pv); + if (val != null) { + if (p != null) + p.val = val; + else { + delta = 1; + t.putTreeVal(h, key, val); + } + } + else if (p != null) { + delta = -1; + if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + break; + } + } + } + if (delta != 0) + addCount((long)delta, binCount); + return val; + } + + /** + * If the specified key is not already associated with a + * (non-null) value, associates it with the given value. + * Otherwise, replaces the value with the results of the given + * remapping function, or removes if {@code null}. The entire + * method invocation is performed atomically. Some attempted + * update operations on this map by other threads may be blocked + * while computation is in progress, so the computation should be + * short and simple, and must not attempt to update any other + * mappings of this Map. + * + * @param key key with which the specified value is to be associated + * @param value the value to use if absent + * @param remappingFunction the function to recompute a value if present + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or the + * remappingFunction is null + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V merge(K key, V value, BiFun remappingFunction) { + if (key == null || value == null || remappingFunction == null) + throw new NullPointerException(); + int h = spread(key.hashCode()); + V val = null; + int delta = 0; + int binCount = 0; + for (Node[] tab = table;;) { + Node f; int n, i, fh; + if (tab == null || (n = tab.length) == 0) + tab = initTable(); + else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { + if (casTabAt(tab, i, null, new Node(h, key, value, null))) { + delta = 1; + val = value; + break; + } + } + else if ((fh = f.hash) == MOVED) + tab = helpTransfer(tab, f); + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + if (fh >= 0) { + binCount = 1; + for (Node e = f, pred = null;; ++binCount) { + K ek; + if (e.hash == h && + ((ek = e.key) == key || + (ek != null && key.equals(ek)))) { + val = remappingFunction.apply(e.val, value); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) { + delta = 1; + val = value; + pred.next = + new Node(h, key, val, null); + break; + } + } + } + else if (f instanceof TreeBin) { + binCount = 2; + TreeBin t = (TreeBin)f; + TreeNode r = t.root; + TreeNode p = (r == null) ? null : + r.findTreeNode(h, key, null); + val = (p == null) ? value : + remappingFunction.apply(p.val, value); + if (val != null) { + if (p != null) + p.val = val; + else { + delta = 1; + t.putTreeVal(h, key, val); + } + } + else if (p != null) { + delta = -1; + if (t.removeTreeNode(p)) + setTabAt(tab, i, untreeify(t.first)); + } + } + } + } + if (binCount != 0) { + if (binCount >= TREEIFY_THRESHOLD) + treeifyBin(tab, i); + break; + } + } + } + if (delta != 0) + addCount((long)delta, binCount); + return val; + } + + // Hashtable legacy methods + + /** + * Legacy method testing if some key maps into the specified value + * in this table. This method is identical in functionality to + * {@link #containsValue(Object)}, and exists solely to ensure + * full compatibility with class {@link java.util.Hashtable}, + * which supported this method prior to introduction of the + * Java Collections framework. + * + * @param value a value to search for + * @return {@code true} if and only if some key maps to the + * {@code value} argument in this table as + * determined by the {@code equals} method; + * {@code false} otherwise + * @throws NullPointerException if the specified value is null + */ + @Deprecated public boolean contains(Object value) { + return containsValue(value); + } + + /** + * Returns an enumeration of the keys in this table. + * + * @return an enumeration of the keys in this table + * @see #keySet() + */ + public Enumeration keys() { + Node[] t; + int f = (t = table) == null ? 0 : t.length; + return new KeyIterator(t, f, 0, f, this); + } + + /** + * Returns an enumeration of the values in this table. + * + * @return an enumeration of the values in this table + * @see #values() + */ + public Enumeration elements() { + Node[] t; + int f = (t = table) == null ? 0 : t.length; + return new ValueIterator(t, f, 0, f, this); + } + + // ConcurrentHashMapV8-only methods /** - * Base class for key, value, and entry iterators. Adds a map - * reference to InternalIterator to support Iterator.remove. + * Returns the number of mappings. This method should be used + * instead of {@link #size} because a ConcurrentHashMapV8 may + * contain more mappings than can be represented as an int. The + * value returned is an estimate; the actual count may differ if + * there are concurrent insertions or removals. + * + * @return the number of mappings + * @since 1.8 */ - static abstract class ViewIterator extends InternalIterator { - final ConcurrentHashMapV8 map; - ViewIterator(ConcurrentHashMapV8 map) { - super(map.table); + public long mappingCount() { + long n = sumCount(); + return (n < 0L) ? 0L : n; // ignore transient negative values + } + + /** + * Creates a new {@link Set} backed by a ConcurrentHashMapV8 + * from the given type to {@code Boolean.TRUE}. + * + * @return the new set + * @since 1.8 + */ + public static KeySetView newKeySet() { + return new KeySetView + (new ConcurrentHashMapV8(), Boolean.TRUE); + } + + /** + * Creates a new {@link Set} backed by a ConcurrentHashMapV8 + * from the given type to {@code Boolean.TRUE}. + * + * @param initialCapacity The implementation performs internal + * sizing to accommodate this many elements. + * @return the new set + * @throws IllegalArgumentException if the initial capacity of + * elements is negative + * @since 1.8 + */ + public static KeySetView newKeySet(int initialCapacity) { + return new KeySetView + (new ConcurrentHashMapV8(initialCapacity), Boolean.TRUE); + } + + /** + * Returns a {@link Set} view of the keys in this map, using the + * given common mapped value for any additions (i.e., {@link + * Collection#add} and {@link Collection#addAll(Collection)}). + * This is of course only appropriate if it is acceptable to use + * the same value for all additions from this view. + * + * @param mappedValue the mapped value to use for any additions + * @return the set view + * @throws NullPointerException if the mappedValue is null + */ + public KeySetView keySet(V mappedValue) { + if (mappedValue == null) + throw new NullPointerException(); + return new KeySetView(this, mappedValue); + } + + /* ---------------- Special Nodes -------------- */ + + /** + * A node inserted at head of bins during transfer operations. + */ + static final class ForwardingNode extends Node { + final Node[] nextTable; + ForwardingNode(Node[] tab) { + super(MOVED, null, null, null); + this.nextTable = tab; + } + + Node find(int h, Object k) { + // loop to avoid arbitrarily deep recursion on forwarding nodes + outer: for (Node[] tab = nextTable;;) { + Node e; int n; + if (k == null || tab == null || (n = tab.length) == 0 || + (e = tabAt(tab, (n - 1) & h)) == null) + return null; + for (;;) { + int eh; K ek; + if ((eh = e.hash) == h && + ((ek = e.key) == k || (ek != null && k.equals(ek)))) + return e; + if (eh < 0) { + if (e instanceof ForwardingNode) { + tab = ((ForwardingNode)e).nextTable; + continue outer; + } + else + return e.find(h, k); + } + if ((e = e.next) == null) + return null; + } + } + } + } + + /** + * A place-holder node used in computeIfAbsent and compute + */ + static final class ReservationNode extends Node { + ReservationNode() { + super(RESERVED, null, null, null); + } + + Node find(int h, Object k) { + return null; + } + } + + /* ---------------- Table Initialization and Resizing -------------- */ + + /** + * Initializes table, using the size recorded in sizeCtl. + */ + private final Node[] initTable() { + Node[] tab; int sc; + while ((tab = table) == null || tab.length == 0) { + if ((sc = sizeCtl) < 0) + Thread.yield(); // lost initialization race; just spin + else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if ((tab = table) == null || tab.length == 0) { + int n = (sc > 0) ? sc : DEFAULT_CAPACITY; + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] nt = (Node[])new Node[n]; + table = tab = nt; + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + break; + } + } + return tab; + } + + /** + * Adds to count, and if table is too small and not already + * resizing, initiates transfer. If already resizing, helps + * perform transfer if work is available. Rechecks occupancy + * after a transfer to see if another resize is already needed + * because resizings are lagging additions. + * + * @param x the count to add + * @param check if <0, don't check resize, if <= 1 only check if uncontended + */ + private final void addCount(long x, int check) { + CounterCell[] as; long b, s; + if ((as = counterCells) != null || + !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) { + CounterHashCode hc; CounterCell a; long v; int m; + boolean uncontended = true; + if ((hc = threadCounterHashCode.get()) == null || + as == null || (m = as.length - 1) < 0 || + (a = as[m & hc.code]) == null || + !(uncontended = + U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) { + fullAddCount(x, hc, uncontended); + return; + } + if (check <= 1) + return; + s = sumCount(); + } + if (check >= 0) { + Node[] tab, nt; int sc; + while (s >= (long)(sc = sizeCtl) && (tab = table) != null && + tab.length < MAXIMUM_CAPACITY) { + if (sc < 0) { + if (sc == -1 || transferIndex <= transferOrigin || + (nt = nextTable) == null) + break; + if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) + transfer(tab, nt); + } + else if (U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + s = sumCount(); + } + } + } + + /** + * Helps transfer if a resize is in progress. + */ + final Node[] helpTransfer(Node[] tab, Node f) { + Node[] nextTab; int sc; + if ((f instanceof ForwardingNode) && + (nextTab = ((ForwardingNode)f).nextTable) != null) { + if (nextTab == nextTable && tab == table && + transferIndex > transferOrigin && (sc = sizeCtl) < -1 && + U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) + transfer(tab, nextTab); + return nextTab; + } + return table; + } + + /** + * Tries to presize table to accommodate the given number of elements. + * + * @param size number of elements (doesn't need to be perfectly accurate) + */ + private final void tryPresize(int size) { + int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : + tableSizeFor(size + (size >>> 1) + 1); + int sc; + while ((sc = sizeCtl) >= 0) { + Node[] tab = table; int n; + if (tab == null || (n = tab.length) == 0) { + n = (sc > c) ? sc : c; + if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if (table == tab) { + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] nt = (Node[])new Node[n]; + table = nt; + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + } + } + else if (c <= sc || n >= MAXIMUM_CAPACITY) + break; + else if (tab == table && + U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + } + } + + /** + * Moves and/or copies the nodes in each bin to new table. See + * above for explanation. + */ + private final void transfer(Node[] tab, Node[] nextTab) { + int n = tab.length, stride; + if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) + stride = MIN_TRANSFER_STRIDE; // subdivide range + if (nextTab == null) { // initiating + try { + @SuppressWarnings({"rawtypes","unchecked"}) + Node[] nt = (Node[])new Node[n << 1]; + nextTab = nt; + } catch (Throwable ex) { // try to cope with OOME + sizeCtl = Integer.MAX_VALUE; + return; + } + nextTable = nextTab; + transferOrigin = n; + transferIndex = n; + ForwardingNode rev = new ForwardingNode(tab); + for (int k = n; k > 0;) { // progressively reveal ready slots + int nextk = (k > stride) ? k - stride : 0; + for (int m = nextk; m < k; ++m) + nextTab[m] = rev; + for (int m = n + nextk; m < n + k; ++m) + nextTab[m] = rev; + U.putOrderedInt(this, TRANSFERORIGIN, k = nextk); + } + } + int nextn = nextTab.length; + ForwardingNode fwd = new ForwardingNode(nextTab); + boolean advance = true; + boolean finishing = false; // to ensure sweep before committing nextTab + for (int i = 0, bound = 0;;) { + int nextIndex, nextBound, fh; Node f; + while (advance) { + if (--i >= bound || finishing) + advance = false; + else if ((nextIndex = transferIndex) <= transferOrigin) { + i = -1; + advance = false; + } + else if (U.compareAndSwapInt + (this, TRANSFERINDEX, nextIndex, + nextBound = (nextIndex > stride ? + nextIndex - stride : 0))) { + bound = nextBound; + i = nextIndex - 1; + advance = false; + } + } + if (i < 0 || i >= n || i + n >= nextn) { + if (finishing) { + nextTable = null; + table = nextTab; + sizeCtl = (n << 1) - (n >>> 1); + return; + } + for (int sc;;) { + if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) { + if (sc != -1) + return; + finishing = advance = true; + i = n; // recheck before commit + break; + } + } + } + else if ((f = tabAt(tab, i)) == null) { + if (casTabAt(tab, i, null, fwd)) { + setTabAt(nextTab, i, null); + setTabAt(nextTab, i + n, null); + advance = true; + } + } + else if ((fh = f.hash) == MOVED) + advance = true; // already processed + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + Node ln, hn; + if (fh >= 0) { + int runBit = fh & n; + Node lastRun = f; + for (Node p = f.next; p != null; p = p.next) { + int b = p.hash & n; + if (b != runBit) { + runBit = b; + lastRun = p; + } + } + if (runBit == 0) { + ln = lastRun; + hn = null; + } + else { + hn = lastRun; + ln = null; + } + for (Node p = f; p != lastRun; p = p.next) { + int ph = p.hash; K pk = p.key; V pv = p.val; + if ((ph & n) == 0) + ln = new Node(ph, pk, pv, ln); + else + hn = new Node(ph, pk, pv, hn); + } + setTabAt(nextTab, i, ln); + setTabAt(nextTab, i + n, hn); + setTabAt(tab, i, fwd); + advance = true; + } + else if (f instanceof TreeBin) { + TreeBin t = (TreeBin)f; + TreeNode lo = null, loTail = null; + TreeNode hi = null, hiTail = null; + int lc = 0, hc = 0; + for (Node e = t.first; e != null; e = e.next) { + int h = e.hash; + TreeNode p = new TreeNode + (h, e.key, e.val, null, null); + if ((h & n) == 0) { + if ((p.prev = loTail) == null) + lo = p; + else + loTail.next = p; + loTail = p; + ++lc; + } + else { + if ((p.prev = hiTail) == null) + hi = p; + else + hiTail.next = p; + hiTail = p; + ++hc; + } + } + ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) : + (hc != 0) ? new TreeBin(lo) : t; + hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) : + (lc != 0) ? new TreeBin(hi) : t; + setTabAt(nextTab, i, ln); + setTabAt(nextTab, i + n, hn); + setTabAt(tab, i, fwd); + advance = true; + } + } + } + } + } + } + + /* ---------------- Conversion from/to TreeBins -------------- */ + + /** + * Replaces all linked nodes in bin at given index unless table is + * too small, in which case resizes instead. + */ + private final void treeifyBin(Node[] tab, int index) { + Node b; int n, sc; + if (tab != null) { + if ((n = tab.length) < MIN_TREEIFY_CAPACITY) { + if (tab == table && (sc = sizeCtl) >= 0 && + U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + } + else if ((b = tabAt(tab, index)) != null && b.hash >= 0) { + synchronized (b) { + if (tabAt(tab, index) == b) { + TreeNode hd = null, tl = null; + for (Node e = b; e != null; e = e.next) { + TreeNode p = + new TreeNode(e.hash, e.key, e.val, + null, null); + if ((p.prev = tl) == null) + hd = p; + else + tl.next = p; + tl = p; + } + setTabAt(tab, index, new TreeBin(hd)); + } + } + } + } + } + + /** + * Returns a list on non-TreeNodes replacing those in given list. + */ + static Node untreeify(Node b) { + Node hd = null, tl = null; + for (Node q = b; q != null; q = q.next) { + Node p = new Node(q.hash, q.key, q.val, null); + if (tl == null) + hd = p; + else + tl.next = p; + tl = p; + } + return hd; + } + + /* ---------------- TreeNodes -------------- */ + + /** + * Nodes for use in TreeBins + */ + static final class TreeNode extends Node { + TreeNode parent; // red-black tree links + TreeNode left; + TreeNode right; + TreeNode prev; // needed to unlink next upon deletion + boolean red; + + TreeNode(int hash, K key, V val, Node next, + TreeNode parent) { + super(hash, key, val, next); + this.parent = parent; + } + + Node find(int h, Object k) { + return findTreeNode(h, k, null); + } + + /** + * Returns the TreeNode (or null if not found) for the given key + * starting at given root. + */ + final TreeNode findTreeNode(int h, Object k, Class kc) { + if (k != null) { + TreeNode p = this; + do { + int ph, dir; K pk; TreeNode q; + TreeNode pl = p.left, pr = p.right; + if ((ph = p.hash) > h) + p = pl; + else if (ph < h) + p = pr; + else if ((pk = p.key) == k || (pk != null && k.equals(pk))) + return p; + else if (pl == null && pr == null) + break; + else if ((kc != null || + (kc = comparableClassFor(k)) != null) && + (dir = compareComparables(kc, k, pk)) != 0) + p = (dir < 0) ? pl : pr; + else if (pl == null) + p = pr; + else if (pr == null || + (q = pr.findTreeNode(h, k, kc)) == null) + p = pl; + else + return q; + } while (p != null); + } + return null; + } + } + + /* ---------------- TreeBins -------------- */ + + /** + * TreeNodes used at the heads of bins. TreeBins do not hold user + * keys or values, but instead point to list of TreeNodes and + * their root. They also maintain a parasitic read-write lock + * forcing writers (who hold bin lock) to wait for readers (who do + * not) to complete before tree restructuring operations. + */ + static final class TreeBin extends Node { + TreeNode root; + volatile TreeNode first; + volatile Thread waiter; + volatile int lockState; + // values for lockState + static final int WRITER = 1; // set while holding write lock + static final int WAITER = 2; // set when waiting for write lock + static final int READER = 4; // increment value for setting read lock + + /** + * Creates bin with initial set of nodes headed by b. + */ + TreeBin(TreeNode b) { + super(TREEBIN, null, null, null); + this.first = b; + TreeNode r = null; + for (TreeNode x = b, next; x != null; x = next) { + next = (TreeNode)x.next; + x.left = x.right = null; + if (r == null) { + x.parent = null; + x.red = false; + r = x; + } + else { + Object key = x.key; + int hash = x.hash; + Class kc = null; + for (TreeNode p = r;;) { + int dir, ph; + if ((ph = p.hash) > hash) + dir = -1; + else if (ph < hash) + dir = 1; + else if ((kc != null || + (kc = comparableClassFor(key)) != null)) + dir = compareComparables(kc, key, p.key); + else + dir = 0; + TreeNode xp = p; + if ((p = (dir <= 0) ? p.left : p.right) == null) { + x.parent = xp; + if (dir <= 0) + xp.left = x; + else + xp.right = x; + r = balanceInsertion(r, x); + break; + } + } + } + } + this.root = r; + } + + /** + * Acquires write lock for tree restructuring. + */ + private final void lockRoot() { + if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER)) + contendedLock(); // offload to separate method + } + + /** + * Releases write lock for tree restructuring. + */ + private final void unlockRoot() { + lockState = 0; + } + + /** + * Possibly blocks awaiting root lock. + */ + private final void contendedLock() { + boolean waiting = false; + for (int s;;) { + if (((s = lockState) & WRITER) == 0) { + if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) { + if (waiting) + waiter = null; + return; + } + } + else if ((s | WAITER) == 0) { + if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) { + waiting = true; + waiter = Thread.currentThread(); + } + } + else if (waiting) + LockSupport.park(this); + } + } + + /** + * Returns matching node or null if none. Tries to search + * using tree comparisons from root, but continues linear + * search when lock not available. + */ + final Node find(int h, Object k) { + if (k != null) { + for (Node e = first; e != null; e = e.next) { + int s; K ek; + if (((s = lockState) & (WAITER|WRITER)) != 0) { + if (e.hash == h && + ((ek = e.key) == k || (ek != null && k.equals(ek)))) + return e; + } + else if (U.compareAndSwapInt(this, LOCKSTATE, s, + s + READER)) { + TreeNode r, p; + try { + p = ((r = root) == null ? null : + r.findTreeNode(h, k, null)); + } finally { + Thread w; + int ls; + do {} while (!U.compareAndSwapInt + (this, LOCKSTATE, + ls = lockState, ls - READER)); + if (ls == (READER|WAITER) && (w = waiter) != null) + LockSupport.unpark(w); + } + return p; + } + } + } + return null; + } + + /** + * Finds or adds a node. + * @return null if added + */ + final TreeNode putTreeVal(int h, K k, V v) { + Class kc = null; + for (TreeNode p = root;;) { + int dir, ph; K pk; TreeNode q, pr; + if (p == null) { + first = root = new TreeNode(h, k, v, null, null); + break; + } + else if ((ph = p.hash) > h) + dir = -1; + else if (ph < h) + dir = 1; + else if ((pk = p.key) == k || (pk != null && k.equals(pk))) + return p; + else if ((kc == null && + (kc = comparableClassFor(k)) == null) || + (dir = compareComparables(kc, k, pk)) == 0) { + if (p.left == null) + dir = 1; + else if ((pr = p.right) == null || + (q = pr.findTreeNode(h, k, kc)) == null) + dir = -1; + else + return q; + } + TreeNode xp = p; + if ((p = (dir < 0) ? p.left : p.right) == null) { + TreeNode x, f = first; + first = x = new TreeNode(h, k, v, f, xp); + if (f != null) + f.prev = x; + if (dir < 0) + xp.left = x; + else + xp.right = x; + if (!xp.red) + x.red = true; + else { + lockRoot(); + try { + root = balanceInsertion(root, x); + } finally { + unlockRoot(); + } + } + break; + } + } + assert checkInvariants(root); + return null; + } + + /** + * Removes the given node, that must be present before this + * call. This is messier than typical red-black deletion code + * because we cannot swap the contents of an interior node + * with a leaf successor that is pinned by "next" pointers + * that are accessible independently of lock. So instead we + * swap the tree linkages. + * + * @return true if now too small, so should be untreeified + */ + final boolean removeTreeNode(TreeNode p) { + TreeNode next = (TreeNode)p.next; + TreeNode pred = p.prev; // unlink traversal pointers + TreeNode r, rl; + if (pred == null) + first = next; + else + pred.next = next; + if (next != null) + next.prev = pred; + if (first == null) { + root = null; + return true; + } + if ((r = root) == null || r.right == null || // too small + (rl = r.left) == null || rl.left == null) + return true; + lockRoot(); + try { + TreeNode replacement; + TreeNode pl = p.left; + TreeNode pr = p.right; + if (pl != null && pr != null) { + TreeNode s = pr, sl; + while ((sl = s.left) != null) // find successor + s = sl; + boolean c = s.red; s.red = p.red; p.red = c; // swap colors + TreeNode sr = s.right; + TreeNode pp = p.parent; + if (s == pr) { // p was s's direct parent + p.parent = s; + s.right = p; + } + else { + TreeNode sp = s.parent; + if ((p.parent = sp) != null) { + if (s == sp.left) + sp.left = p; + else + sp.right = p; + } + if ((s.right = pr) != null) + pr.parent = s; + } + p.left = null; + if ((p.right = sr) != null) + sr.parent = p; + if ((s.left = pl) != null) + pl.parent = s; + if ((s.parent = pp) == null) + r = s; + else if (p == pp.left) + pp.left = s; + else + pp.right = s; + if (sr != null) + replacement = sr; + else + replacement = p; + } + else if (pl != null) + replacement = pl; + else if (pr != null) + replacement = pr; + else + replacement = p; + if (replacement != p) { + TreeNode pp = replacement.parent = p.parent; + if (pp == null) + r = replacement; + else if (p == pp.left) + pp.left = replacement; + else + pp.right = replacement; + p.left = p.right = p.parent = null; + } + + root = (p.red) ? r : balanceDeletion(r, replacement); + + if (p == replacement) { // detach pointers + TreeNode pp; + if ((pp = p.parent) != null) { + if (p == pp.left) + pp.left = null; + else if (p == pp.right) + pp.right = null; + p.parent = null; + } + } + } finally { + unlockRoot(); + } + assert checkInvariants(root); + return false; + } + + /* ------------------------------------------------------------ */ + // Red-black tree methods, all adapted from CLR + + static TreeNode rotateLeft(TreeNode root, + TreeNode p) { + TreeNode r, pp, rl; + if (p != null && (r = p.right) != null) { + if ((rl = p.right = r.left) != null) + rl.parent = p; + if ((pp = r.parent = p.parent) == null) + (root = r).red = false; + else if (pp.left == p) + pp.left = r; + else + pp.right = r; + r.left = p; + p.parent = r; + } + return root; + } + + static TreeNode rotateRight(TreeNode root, + TreeNode p) { + TreeNode l, pp, lr; + if (p != null && (l = p.left) != null) { + if ((lr = p.left = l.right) != null) + lr.parent = p; + if ((pp = l.parent = p.parent) == null) + (root = l).red = false; + else if (pp.right == p) + pp.right = l; + else + pp.left = l; + l.right = p; + p.parent = l; + } + return root; + } + + static TreeNode balanceInsertion(TreeNode root, + TreeNode x) { + x.red = true; + for (TreeNode xp, xpp, xppl, xppr;;) { + if ((xp = x.parent) == null) { + x.red = false; + return x; + } + else if (!xp.red || (xpp = xp.parent) == null) + return root; + if (xp == (xppl = xpp.left)) { + if ((xppr = xpp.right) != null && xppr.red) { + xppr.red = false; + xp.red = false; + xpp.red = true; + x = xpp; + } + else { + if (x == xp.right) { + root = rotateLeft(root, x = xp); + xpp = (xp = x.parent) == null ? null : xp.parent; + } + if (xp != null) { + xp.red = false; + if (xpp != null) { + xpp.red = true; + root = rotateRight(root, xpp); + } + } + } + } + else { + if (xppl != null && xppl.red) { + xppl.red = false; + xp.red = false; + xpp.red = true; + x = xpp; + } + else { + if (x == xp.left) { + root = rotateRight(root, x = xp); + xpp = (xp = x.parent) == null ? null : xp.parent; + } + if (xp != null) { + xp.red = false; + if (xpp != null) { + xpp.red = true; + root = rotateLeft(root, xpp); + } + } + } + } + } + } + + static TreeNode balanceDeletion(TreeNode root, + TreeNode x) { + for (TreeNode xp, xpl, xpr;;) { + if (x == null || x == root) + return root; + else if ((xp = x.parent) == null) { + x.red = false; + return x; + } + else if (x.red) { + x.red = false; + return root; + } + else if ((xpl = xp.left) == x) { + if ((xpr = xp.right) != null && xpr.red) { + xpr.red = false; + xp.red = true; + root = rotateLeft(root, xp); + xpr = (xp = x.parent) == null ? null : xp.right; + } + if (xpr == null) + x = xp; + else { + TreeNode sl = xpr.left, sr = xpr.right; + if ((sr == null || !sr.red) && + (sl == null || !sl.red)) { + xpr.red = true; + x = xp; + } + else { + if (sr == null || !sr.red) { + if (sl != null) + sl.red = false; + xpr.red = true; + root = rotateRight(root, xpr); + xpr = (xp = x.parent) == null ? + null : xp.right; + } + if (xpr != null) { + xpr.red = (xp == null) ? false : xp.red; + if ((sr = xpr.right) != null) + sr.red = false; + } + if (xp != null) { + xp.red = false; + root = rotateLeft(root, xp); + } + x = root; + } + } + } + else { // symmetric + if (xpl != null && xpl.red) { + xpl.red = false; + xp.red = true; + root = rotateRight(root, xp); + xpl = (xp = x.parent) == null ? null : xp.left; + } + if (xpl == null) + x = xp; + else { + TreeNode sl = xpl.left, sr = xpl.right; + if ((sl == null || !sl.red) && + (sr == null || !sr.red)) { + xpl.red = true; + x = xp; + } + else { + if (sl == null || !sl.red) { + if (sr != null) + sr.red = false; + xpl.red = true; + root = rotateLeft(root, xpl); + xpl = (xp = x.parent) == null ? + null : xp.left; + } + if (xpl != null) { + xpl.red = (xp == null) ? false : xp.red; + if ((sl = xpl.left) != null) + sl.red = false; + } + if (xp != null) { + xp.red = false; + root = rotateRight(root, xp); + } + x = root; + } + } + } + } + } + + /** + * Recursive invariant check + */ + static boolean checkInvariants(TreeNode t) { + TreeNode tp = t.parent, tl = t.left, tr = t.right, + tb = t.prev, tn = (TreeNode)t.next; + if (tb != null && tb.next != t) + return false; + if (tn != null && tn.prev != t) + return false; + if (tp != null && t != tp.left && t != tp.right) + return false; + if (tl != null && (tl.parent != t || tl.hash > t.hash)) + return false; + if (tr != null && (tr.parent != t || tr.hash < t.hash)) + return false; + if (t.red && tl != null && tl.red && tr != null && tr.red) + return false; + if (tl != null && !checkInvariants(tl)) + return false; + if (tr != null && !checkInvariants(tr)) + return false; + return true; + } + + private static final sun.misc.Unsafe U; + private static final long LOCKSTATE; + static { + try { + U = getUnsafe(); + Class k = TreeBin.class; + LOCKSTATE = U.objectFieldOffset + (k.getDeclaredField("lockState")); + } catch (Exception e) { + throw new Error(e); + } + } + } + + /* ----------------Table Traversal -------------- */ + + /** + * Encapsulates traversal for methods such as containsValue; also + * serves as a base class for other iterators and spliterators. + * + * Method advance visits once each still-valid node that was + * reachable upon iterator construction. It might miss some that + * were added to a bin after the bin was visited, which is OK wrt + * consistency guarantees. Maintaining this property in the face + * of possible ongoing resizes requires a fair amount of + * bookkeeping state that is difficult to optimize away amidst + * volatile accesses. Even so, traversal maintains reasonable + * throughput. + * + * Normally, iteration proceeds bin-by-bin traversing lists. + * However, if the table has been resized, then all future steps + * must traverse both the bin at the current index as well as at + * (index + baseSize); and so on for further resizings. To + * paranoically cope with potential sharing by users of iterators + * across threads, iteration terminates if a bounds checks fails + * for a table read. + */ + static class Traverser { + Node[] tab; // current table; updated if resized + Node next; // the next entry to use + int index; // index of bin to use next + int baseIndex; // current index of initial table + int baseLimit; // index bound for initial table + final int baseSize; // initial table size + + Traverser(Node[] tab, int size, int index, int limit) { + this.tab = tab; + this.baseSize = size; + this.baseIndex = this.index = index; + this.baseLimit = limit; + this.next = null; + } + + /** + * Advances if possible, returning next valid node, or null if none. + */ + final Node advance() { + Node e; + if ((e = next) != null) + e = e.next; + for (;;) { + Node[] t; int i, n; K ek; // must use locals in checks + if (e != null) + return next = e; + if (baseIndex >= baseLimit || (t = tab) == null || + (n = t.length) <= (i = index) || i < 0) + return next = null; + if ((e = tabAt(t, index)) != null && e.hash < 0) { + if (e instanceof ForwardingNode) { + tab = ((ForwardingNode)e).nextTable; + e = null; + continue; + } + else if (e instanceof TreeBin) + e = ((TreeBin)e).first; + else + e = null; + } + if ((index += baseSize) >= n) + index = ++baseIndex; // visit upper slots if present + } + } + } + + /** + * Base of key, value, and entry Iterators. Adds fields to + * Traverser to support iterator.remove. + */ + static class BaseIterator extends Traverser { + final ConcurrentHashMapV8 map; + Node lastReturned; + BaseIterator(Node[] tab, int size, int index, int limit, + ConcurrentHashMapV8 map) { + super(tab, size, index, limit); this.map = map; + advance(); } + public final boolean hasNext() { return next != null; } + public final boolean hasMoreElements() { return next != null; } + public final void remove() { - if (last == null) + Node p; + if ((p = lastReturned) == null) throw new IllegalStateException(); - map.remove(last.key); - last = null; + lastReturned = null; + map.replaceNode(p.key, null, null); } - - public final boolean hasNext() { return next != null; } - public final boolean hasMoreElements() { return next != null; } } - static final class KeyIterator extends ViewIterator + static final class KeyIterator extends BaseIterator implements Iterator, Enumeration { - KeyIterator(ConcurrentHashMapV8 map) { super(map); } + KeyIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMapV8 map) { + super(tab, index, size, limit, map); + } - @SuppressWarnings("unchecked") public final K next() { - if (next == null) + Node p; + if ((p = next) == null) throw new NoSuchElementException(); - Object k = nextKey; + K k = p.key; + lastReturned = p; advance(); - return (K)k; + return k; } public final K nextElement() { return next(); } } - static final class ValueIterator extends ViewIterator + static final class ValueIterator extends BaseIterator implements Iterator, Enumeration { - ValueIterator(ConcurrentHashMapV8 map) { super(map); } + ValueIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMapV8 map) { + super(tab, index, size, limit, map); + } - @SuppressWarnings("unchecked") public final V next() { - if (next == null) + Node p; + if ((p = next) == null) throw new NoSuchElementException(); - Object v = nextVal; + V v = p.val; + lastReturned = p; advance(); - return (V)v; + return v; } public final V nextElement() { return next(); } } - static final class EntryIterator extends ViewIterator + static final class EntryIterator extends BaseIterator implements Iterator> { - EntryIterator(ConcurrentHashMapV8 map) { super(map); } + EntryIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMapV8 map) { + super(tab, index, size, limit, map); + } - @SuppressWarnings("unchecked") public final Map.Entry next() { - if (next == null) + Node p; + if ((p = next) == null) throw new NoSuchElementException(); - Object k = nextKey; - Object v = nextVal; + K k = p.key; + V v = p.val; + lastReturned = p; advance(); - return new WriteThroughEntry(map, (K)k, (V)v); + return new MapEntry(k, v, map); } } /** - * Custom Entry class used by EntryIterator.next(), that relays - * setValue changes to the underlying map. + * Exported Entry for EntryIterator */ - static final class WriteThroughEntry implements Map.Entry { - final ConcurrentHashMapV8 map; + static final class MapEntry implements Map.Entry { final K key; // non-null V val; // non-null - WriteThroughEntry(ConcurrentHashMapV8 map, K key, V val) { - this.map = map; this.key = key; this.val = val; + final ConcurrentHashMapV8 map; + MapEntry(K key, V val, ConcurrentHashMapV8 map) { + this.key = key; + this.val = val; + this.map = map; } + public K getKey() { return key; } + public V getValue() { return val; } + public int hashCode() { return key.hashCode() ^ val.hashCode(); } + public String toString() { return key + "=" + val; } - public final K getKey() { return key; } - public final V getValue() { return val; } - public final int hashCode() { return key.hashCode() ^ val.hashCode(); } - public final String toString(){ return key + "=" + val; } - - public final boolean equals(Object o) { + public boolean equals(Object o) { Object k, v; Map.Entry e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry)o).getKey()) != null && @@ -1494,14 +3275,13 @@ public class ConcurrentHashMapV8 /** * Sets our entry's value and writes through to the map. The - * value to return is somewhat arbitrary here. Since a - * WriteThroughEntry does not necessarily track asynchronous - * changes, the most recent "previous" value could be - * different from what we return (or could even have been - * removed in which case the put will re-establish). We do not - * and cannot guarantee more. + * value to return is somewhat arbitrary here. Since we do not + * necessarily track asynchronous changes, the most recent + * "previous" value could be different from what we return (or + * could even have been removed, in which case the put will + * re-establish). We do not and cannot guarantee more. */ - public final V setValue(V value) { + public V setValue(V value) { if (value == null) throw new NullPointerException(); V v = val; val = value; @@ -1510,52 +3290,1196 @@ public class ConcurrentHashMapV8 } } + static final class KeySpliterator extends Traverser + implements ConcurrentHashMapSpliterator { + long est; // size estimate + KeySpliterator(Node[] tab, int size, int index, int limit, + long est) { + super(tab, size, index, limit); + this.est = est; + } + + public ConcurrentHashMapSpliterator trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new KeySpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1); + } + + public void forEachRemaining(Action action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null;) + action.apply(p.key); + } + + public boolean tryAdvance(Action action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.apply(p.key); + return true; + } + + public long estimateSize() { return est; } + + } + + static final class ValueSpliterator extends Traverser + implements ConcurrentHashMapSpliterator { + long est; // size estimate + ValueSpliterator(Node[] tab, int size, int index, int limit, + long est) { + super(tab, size, index, limit); + this.est = est; + } + + public ConcurrentHashMapSpliterator trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new ValueSpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1); + } + + public void forEachRemaining(Action action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null;) + action.apply(p.val); + } + + public boolean tryAdvance(Action action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.apply(p.val); + return true; + } + + public long estimateSize() { return est; } + + } + + static final class EntrySpliterator extends Traverser + implements ConcurrentHashMapSpliterator> { + final ConcurrentHashMapV8 map; // To export MapEntry + long est; // size estimate + EntrySpliterator(Node[] tab, int size, int index, int limit, + long est, ConcurrentHashMapV8 map) { + super(tab, size, index, limit); + this.map = map; + this.est = est; + } + + public ConcurrentHashMapSpliterator> trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new EntrySpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1, map); + } + + public void forEachRemaining(Action> action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null; ) + action.apply(new MapEntry(p.key, p.val, map)); + } + + public boolean tryAdvance(Action> action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.apply(new MapEntry(p.key, p.val, map)); + return true; + } + + public long estimateSize() { return est; } + + } + + // Parallel bulk operations + + /** + * Computes initial batch value for bulk tasks. The returned value + * is approximately exp2 of the number of times (minus one) to + * split task by two before executing leaf action. This value is + * faster to compute and more convenient to use as a guide to + * splitting than is the depth, since it is used while dividing by + * two anyway. + */ + final int batchFor(long b) { + long n; + if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b) + return 0; + int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4 + return (b <= 0L || (n /= b) >= sp) ? sp : (int)n; + } + + /** + * Performs the given action for each (key, value). + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + * @since 1.8 + */ + public void forEach(long parallelismThreshold, + BiAction action) { + if (action == null) throw new NullPointerException(); + new ForEachMappingTask + (null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each (key, value). + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + * @since 1.8 + */ + public void forEach(long parallelismThreshold, + BiFun transformer, + Action action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedMappingTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each (key, value), or null if none. Upon + * success, further element processing is suppressed and the + * results of any other parallel invocations of the search + * function are ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each (key, value), or null if none + * @since 1.8 + */ + public U search(long parallelismThreshold, + BiFun searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchMappingsTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + * @since 1.8 + */ + public U reduce(long parallelismThreshold, + BiFun transformer, + BiFun reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + * @since 1.8 + */ + public double reduceToDouble(long parallelismThreshold, + ObjectByObjectToDouble transformer, + double basis, + DoubleByDoubleToDouble reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + * @since 1.8 + */ + public long reduceToLong(long parallelismThreshold, + ObjectByObjectToLong transformer, + long basis, + LongByLongToLong reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + * @since 1.8 + */ + public int reduceToInt(long parallelismThreshold, + ObjectByObjectToInt transformer, + int basis, + IntByIntToInt reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Performs the given action for each key. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + * @since 1.8 + */ + public void forEachKey(long parallelismThreshold, + Action action) { + if (action == null) throw new NullPointerException(); + new ForEachKeyTask + (null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each key. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + * @since 1.8 + */ + public void forEachKey(long parallelismThreshold, + Fun transformer, + Action action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedKeyTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each key, or null if none. Upon success, + * further element processing is suppressed and the results of + * any other parallel invocations of the search function are + * ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each key, or null if none + * @since 1.8 + */ + public U searchKeys(long parallelismThreshold, + Fun searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchKeysTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating all keys using the given + * reducer to combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param reducer a commutative associative combining function + * @return the result of accumulating all keys using the given + * reducer to combine values, or null if none + * @since 1.8 + */ + public K reduceKeys(long parallelismThreshold, + BiFun reducer) { + if (reducer == null) throw new NullPointerException(); + return new ReduceKeysTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, or + * null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + * @since 1.8 + */ + public U reduceKeys(long parallelismThreshold, + Fun transformer, + BiFun reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, and + * the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + * @since 1.8 + */ + public double reduceKeysToDouble(long parallelismThreshold, + ObjectToDouble transformer, + double basis, + DoubleByDoubleToDouble reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, and + * the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + * @since 1.8 + */ + public long reduceKeysToLong(long parallelismThreshold, + ObjectToLong transformer, + long basis, + LongByLongToLong reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, and + * the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + * @since 1.8 + */ + public int reduceKeysToInt(long parallelismThreshold, + ObjectToInt transformer, + int basis, + IntByIntToInt reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Performs the given action for each value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + * @since 1.8 + */ + public void forEachValue(long parallelismThreshold, + Action action) { + if (action == null) + throw new NullPointerException(); + new ForEachValueTask + (null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + * @since 1.8 + */ + public void forEachValue(long parallelismThreshold, + Fun transformer, + Action action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedValueTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each value, or null if none. Upon success, + * further element processing is suppressed and the results of + * any other parallel invocations of the search function are + * ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each value, or null if none + * @since 1.8 + */ + public U searchValues(long parallelismThreshold, + Fun searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchValuesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating all values using the + * given reducer to combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param reducer a commutative associative combining function + * @return the result of accumulating all values + * @since 1.8 + */ + public V reduceValues(long parallelismThreshold, + BiFun reducer) { + if (reducer == null) throw new NullPointerException(); + return new ReduceValuesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, or + * null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + * @since 1.8 + */ + public U reduceValues(long parallelismThreshold, + Fun transformer, + BiFun reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + * @since 1.8 + */ + public double reduceValuesToDouble(long parallelismThreshold, + ObjectToDouble transformer, + double basis, + DoubleByDoubleToDouble reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + * @since 1.8 + */ + public long reduceValuesToLong(long parallelismThreshold, + ObjectToLong transformer, + long basis, + LongByLongToLong reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + * @since 1.8 + */ + public int reduceValuesToInt(long parallelismThreshold, + ObjectToInt transformer, + int basis, + IntByIntToInt reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Performs the given action for each entry. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + * @since 1.8 + */ + public void forEachEntry(long parallelismThreshold, + Action> action) { + if (action == null) throw new NullPointerException(); + new ForEachEntryTask(null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each entry. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + * @since 1.8 + */ + public void forEachEntry(long parallelismThreshold, + Fun, ? extends U> transformer, + Action action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedEntryTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each entry, or null if none. Upon success, + * further element processing is suppressed and the results of + * any other parallel invocations of the search function are + * ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each entry, or null if none + * @since 1.8 + */ + public U searchEntries(long parallelismThreshold, + Fun, ? extends U> searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchEntriesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating all entries using the + * given reducer to combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param reducer a commutative associative combining function + * @return the result of accumulating all entries + * @since 1.8 + */ + public Map.Entry reduceEntries(long parallelismThreshold, + BiFun, Map.Entry, ? extends Map.Entry> reducer) { + if (reducer == null) throw new NullPointerException(); + return new ReduceEntriesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + * @since 1.8 + */ + public U reduceEntries(long parallelismThreshold, + Fun, ? extends U> transformer, + BiFun reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + * @since 1.8 + */ + public double reduceEntriesToDouble(long parallelismThreshold, + ObjectToDouble> transformer, + double basis, + DoubleByDoubleToDouble reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + * @since 1.8 + */ + public long reduceEntriesToLong(long parallelismThreshold, + ObjectToLong> transformer, + long basis, + LongByLongToLong reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + * @since 1.8 + */ + public int reduceEntriesToInt(long parallelismThreshold, + ObjectToInt> transformer, + int basis, + IntByIntToInt reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /* ----------------Views -------------- */ - /* - * These currently just extend java.util.AbstractX classes, but - * may need a new custom base to support partitioned traversal. + /** + * Base class for views. */ + abstract static class CollectionView + implements Collection, java.io.Serializable { + private static final long serialVersionUID = 7249069246763182397L; + final ConcurrentHashMapV8 map; + CollectionView(ConcurrentHashMapV8 map) { this.map = map; } + + /** + * Returns the map backing this view. + * + * @return the map backing this view + */ + public ConcurrentHashMapV8 getMap() { return map; } - static final class KeySet extends AbstractSet { - final ConcurrentHashMapV8 map; - KeySet(ConcurrentHashMapV8 map) { this.map = map; } + /** + * Removes all of the elements from this view, by removing all + * the mappings from the map backing this view. + */ + public final void clear() { map.clear(); } + public final int size() { return map.size(); } + public final boolean isEmpty() { return map.isEmpty(); } - public final int size() { return map.size(); } - public final boolean isEmpty() { return map.isEmpty(); } - public final void clear() { map.clear(); } - public final boolean contains(Object o) { return map.containsKey(o); } - public final boolean remove(Object o) { return map.remove(o) != null; } - public final Iterator iterator() { - return new KeyIterator(map); + // implementations below rely on concrete classes supplying these + // abstract methods + /** + * Returns a "weakly consistent" iterator that will never + * throw {@link ConcurrentModificationException}, and + * guarantees to traverse elements as they existed upon + * construction of the iterator, and may (but is not + * guaranteed to) reflect any modifications subsequent to + * construction. + */ + public abstract Iterator iterator(); + public abstract boolean contains(Object o); + public abstract boolean remove(Object o); + + private static final String oomeMsg = "Required array size too large"; + + public final Object[] toArray() { + long sz = map.mappingCount(); + if (sz > MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + int n = (int)sz; + Object[] r = new Object[n]; + int i = 0; + for (E e : this) { + if (i == n) { + if (n >= MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) + n = MAX_ARRAY_SIZE; + else + n += (n >>> 1) + 1; + r = Arrays.copyOf(r, n); + } + r[i++] = e; + } + return (i == n) ? r : Arrays.copyOf(r, i); } - } - static final class Values extends AbstractCollection { - final ConcurrentHashMapV8 map; - Values(ConcurrentHashMapV8 map) { this.map = map; } + @SuppressWarnings("unchecked") + public final T[] toArray(T[] a) { + long sz = map.mappingCount(); + if (sz > MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + int m = (int)sz; + T[] r = (a.length >= m) ? a : + (T[])java.lang.reflect.Array + .newInstance(a.getClass().getComponentType(), m); + int n = r.length; + int i = 0; + for (E e : this) { + if (i == n) { + if (n >= MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) + n = MAX_ARRAY_SIZE; + else + n += (n >>> 1) + 1; + r = Arrays.copyOf(r, n); + } + r[i++] = (T)e; + } + if (a == r && i < n) { + r[i] = null; // null-terminate + return r; + } + return (i == n) ? r : Arrays.copyOf(r, i); + } - public final int size() { return map.size(); } - public final boolean isEmpty() { return map.isEmpty(); } - public final void clear() { map.clear(); } - public final boolean contains(Object o) { return map.containsValue(o); } - public final Iterator iterator() { - return new ValueIterator(map); + /** + * Returns a string representation of this collection. + * The string representation consists of the string representations + * of the collection's elements in the order they are returned by + * its iterator, enclosed in square brackets ({@code "[]"}). + * Adjacent elements are separated by the characters {@code ", "} + * (comma and space). Elements are converted to strings as by + * {@link String#valueOf(Object)}. + * + * @return a string representation of this collection + */ + public final String toString() { + StringBuilder sb = new StringBuilder(); + sb.append('['); + Iterator it = iterator(); + if (it.hasNext()) { + for (;;) { + Object e = it.next(); + sb.append(e == this ? "(this Collection)" : e); + if (!it.hasNext()) + break; + sb.append(',').append(' '); + } + } + return sb.append(']').toString(); + } + + public final boolean containsAll(Collection c) { + if (c != this) { + for (Object e : c) { + if (e == null || !contains(e)) + return false; + } + } + return true; + } + + public final boolean removeAll(Collection c) { + boolean modified = false; + for (Iterator it = iterator(); it.hasNext();) { + if (c.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + public final boolean retainAll(Collection c) { + boolean modified = false; + for (Iterator it = iterator(); it.hasNext();) { + if (!c.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; } + } - static final class EntrySet extends AbstractSet> { - final ConcurrentHashMapV8 map; - EntrySet(ConcurrentHashMapV8 map) { this.map = map; } + /** + * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in + * which additions may optionally be enabled by mapping to a + * common value. This class cannot be directly instantiated. + * See {@link #keySet() keySet()}, + * {@link #keySet(Object) keySet(V)}, + * {@link #newKeySet() newKeySet()}, + * {@link #newKeySet(int) newKeySet(int)}. + * + * @since 1.8 + */ + public static class KeySetView extends CollectionView + implements Set, java.io.Serializable { + private static final long serialVersionUID = 7249069246763182397L; + private final V value; + KeySetView(ConcurrentHashMapV8 map, V value) { // non-public + super(map); + this.value = value; + } + + /** + * Returns the default mapped value for additions, + * or {@code null} if additions are not supported. + * + * @return the default mapped value for additions, or {@code null} + * if not supported + */ + public V getMappedValue() { return value; } - public final int size() { return map.size(); } - public final boolean isEmpty() { return map.isEmpty(); } - public final void clear() { map.clear(); } - public final Iterator> iterator() { - return new EntryIterator(map); + /** + * {@inheritDoc} + * @throws NullPointerException if the specified key is null + */ + public boolean contains(Object o) { return map.containsKey(o); } + + /** + * Removes the key from this map view, by removing the key (and its + * corresponding value) from the backing map. This method does + * nothing if the key is not in the map. + * + * @param o the key to be removed from the backing map + * @return {@code true} if the backing map contained the specified key + * @throws NullPointerException if the specified key is null + */ + public boolean remove(Object o) { return map.remove(o) != null; } + + /** + * @return an iterator over the keys of the backing map + */ + public Iterator iterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + int f = (t = m.table) == null ? 0 : t.length; + return new KeyIterator(t, f, 0, f, m); + } + + /** + * Adds the specified key to this set view by mapping the key to + * the default mapped value in the backing map, if defined. + * + * @param e key to be added + * @return {@code true} if this set changed as a result of the call + * @throws NullPointerException if the specified key is null + * @throws UnsupportedOperationException if no default mapped value + * for additions was provided + */ + public boolean add(K e) { + V v; + if ((v = value) == null) + throw new UnsupportedOperationException(); + return map.putVal(e, v, true) == null; } + /** + * Adds all of the elements in the specified collection to this set, + * as if by calling {@link #add} on each one. + * + * @param c the elements to be inserted into this set + * @return {@code true} if this set changed as a result of the call + * @throws NullPointerException if the collection or any of its + * elements are {@code null} + * @throws UnsupportedOperationException if no default mapped value + * for additions was provided + */ + public boolean addAll(Collection c) { + boolean added = false; + V v; + if ((v = value) == null) + throw new UnsupportedOperationException(); + for (K e : c) { + if (map.putVal(e, v, true) == null) + added = true; + } + return added; + } + + public int hashCode() { + int h = 0; + for (K e : this) + h += e.hashCode(); + return h; + } + + public boolean equals(Object o) { + Set c; + return ((o instanceof Set) && + ((c = (Set)o) == this || + (containsAll(c) && c.containsAll(this)))); + } + + public ConcurrentHashMapSpliterator spliterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new KeySpliterator(t, f, 0, f, n < 0L ? 0L : n); + } + + public void forEach(Action action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.apply(p.key); + } + } + } + + /** + * A view of a ConcurrentHashMapV8 as a {@link Collection} of + * values, in which additions are disabled. This class cannot be + * directly instantiated. See {@link #values()}. + */ + static final class ValuesView extends CollectionView + implements Collection, java.io.Serializable { + private static final long serialVersionUID = 2249069246763182397L; + ValuesView(ConcurrentHashMapV8 map) { super(map); } public final boolean contains(Object o) { + return map.containsValue(o); + } + + public final boolean remove(Object o) { + if (o != null) { + for (Iterator it = iterator(); it.hasNext();) { + if (o.equals(it.next())) { + it.remove(); + return true; + } + } + } + return false; + } + + public final Iterator iterator() { + ConcurrentHashMapV8 m = map; + Node[] t; + int f = (t = m.table) == null ? 0 : t.length; + return new ValueIterator(t, f, 0, f, m); + } + + public final boolean add(V e) { + throw new UnsupportedOperationException(); + } + public final boolean addAll(Collection c) { + throw new UnsupportedOperationException(); + } + + public ConcurrentHashMapSpliterator spliterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new ValueSpliterator(t, f, 0, f, n < 0L ? 0L : n); + } + + public void forEach(Action action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.apply(p.val); + } + } + } + + /** + * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value) + * entries. This class cannot be directly instantiated. See + * {@link #entrySet()}. + */ + static final class EntrySetView extends CollectionView> + implements Set>, java.io.Serializable { + private static final long serialVersionUID = 2249069246763182397L; + EntrySetView(ConcurrentHashMapV8 map) { super(map); } + + public boolean contains(Object o) { Object k, v, r; Map.Entry e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry)o).getKey()) != null && @@ -1564,148 +4488,1677 @@ public class ConcurrentHashMapV8 (v == r || v.equals(r))); } - public final boolean remove(Object o) { + public boolean remove(Object o) { Object k, v; Map.Entry e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry)o).getKey()) != null && (v = e.getValue()) != null && map.remove(k, v)); } + + /** + * @return an iterator over the entries of the backing map + */ + public Iterator> iterator() { + ConcurrentHashMapV8 m = map; + Node[] t; + int f = (t = m.table) == null ? 0 : t.length; + return new EntryIterator(t, f, 0, f, m); + } + + public boolean add(Entry e) { + return map.putVal(e.getKey(), e.getValue(), false) == null; + } + + public boolean addAll(Collection> c) { + boolean added = false; + for (Entry e : c) { + if (add(e)) + added = true; + } + return added; + } + + public final int hashCode() { + int h = 0; + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + h += p.hashCode(); + } + } + return h; + } + + public final boolean equals(Object o) { + Set c; + return ((o instanceof Set) && + ((c = (Set)o) == this || + (containsAll(c) && c.containsAll(this)))); + } + + public ConcurrentHashMapSpliterator> spliterator() { + Node[] t; + ConcurrentHashMapV8 m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new EntrySpliterator(t, f, 0, f, n < 0L ? 0L : n, m); + } + + public void forEach(Action> action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.apply(new MapEntry(p.key, p.val, map)); + } + } + } - /* ---------------- Serialization Support -------------- */ + // ------------------------------------------------------- /** - * Stripped-down version of helper class used in previous version, - * declared for the sake of serialization compatibility + * Base class for bulk tasks. Repeats some fields and code from + * class Traverser, because we need to subclass CountedCompleter. */ - static class Segment implements Serializable { - private static final long serialVersionUID = 2249069246763182397L; - final float loadFactor; - Segment(float lf) { this.loadFactor = lf; } + abstract static class BulkTask extends CountedCompleter { + Node[] tab; // same as Traverser + Node next; + int index; + int baseIndex; + int baseLimit; + final int baseSize; + int batch; // split control + + BulkTask(BulkTask par, int b, int i, int f, Node[] t) { + super(par); + this.batch = b; + this.index = this.baseIndex = i; + if ((this.tab = t) == null) + this.baseSize = this.baseLimit = 0; + else if (par == null) + this.baseSize = this.baseLimit = t.length; + else { + this.baseLimit = f; + this.baseSize = par.baseSize; + } + } + + /** + * Same as Traverser version + */ + final Node advance() { + Node e; + if ((e = next) != null) + e = e.next; + for (;;) { + Node[] t; int i, n; K ek; // must use locals in checks + if (e != null) + return next = e; + if (baseIndex >= baseLimit || (t = tab) == null || + (n = t.length) <= (i = index) || i < 0) + return next = null; + if ((e = tabAt(t, index)) != null && e.hash < 0) { + if (e instanceof ForwardingNode) { + tab = ((ForwardingNode)e).nextTable; + e = null; + continue; + } + else if (e instanceof TreeBin) + e = ((TreeBin)e).first; + else + e = null; + } + if ((index += baseSize) >= n) + index = ++baseIndex; // visit upper slots if present + } + } + } + + /* + * Task classes. Coded in a regular but ugly format/style to + * simplify checks that each variant differs in the right way from + * others. The null screenings exist because compilers cannot tell + * that we've already null-checked task arguments, so we force + * simplest hoisted bypass to help avoid convoluted traps. + */ + @SuppressWarnings("serial") + static final class ForEachKeyTask + extends BulkTask { + final Action action; + ForEachKeyTask + (BulkTask p, int b, int i, int f, Node[] t, + Action action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final Action action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachKeyTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null;) + action.apply(p.key); + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachValueTask + extends BulkTask { + final Action action; + ForEachValueTask + (BulkTask p, int b, int i, int f, Node[] t, + Action action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final Action action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachValueTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null;) + action.apply(p.val); + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachEntryTask + extends BulkTask { + final Action> action; + ForEachEntryTask + (BulkTask p, int b, int i, int f, Node[] t, + Action> action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final Action> action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachEntryTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null; ) + action.apply(p); + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachMappingTask + extends BulkTask { + final BiAction action; + ForEachMappingTask + (BulkTask p, int b, int i, int f, Node[] t, + BiAction action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final BiAction action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachMappingTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null; ) + action.apply(p.key, p.val); + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachTransformedKeyTask + extends BulkTask { + final Fun transformer; + final Action action; + ForEachTransformedKeyTask + (BulkTask p, int b, int i, int f, Node[] t, + Fun transformer, Action action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final Fun transformer; + final Action action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedKeyTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.key)) != null) + action.apply(u); + } + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachTransformedValueTask + extends BulkTask { + final Fun transformer; + final Action action; + ForEachTransformedValueTask + (BulkTask p, int b, int i, int f, Node[] t, + Fun transformer, Action action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final Fun transformer; + final Action action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedValueTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.val)) != null) + action.apply(u); + } + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachTransformedEntryTask + extends BulkTask { + final Fun, ? extends U> transformer; + final Action action; + ForEachTransformedEntryTask + (BulkTask p, int b, int i, int f, Node[] t, + Fun, ? extends U> transformer, Action action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final Fun, ? extends U> transformer; + final Action action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedEntryTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p)) != null) + action.apply(u); + } + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class ForEachTransformedMappingTask + extends BulkTask { + final BiFun transformer; + final Action action; + ForEachTransformedMappingTask + (BulkTask p, int b, int i, int f, Node[] t, + BiFun transformer, + Action action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final BiFun transformer; + final Action action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedMappingTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.key, p.val)) != null) + action.apply(u); + } + propagateCompletion(); + } + } + } + + @SuppressWarnings("serial") + static final class SearchKeysTask + extends BulkTask { + final Fun searchFunction; + final AtomicReference result; + SearchKeysTask + (BulkTask p, int b, int i, int f, Node[] t, + Fun searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final Fun searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchKeysTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply(p.key)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + break; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class SearchValuesTask + extends BulkTask { + final Fun searchFunction; + final AtomicReference result; + SearchValuesTask + (BulkTask p, int b, int i, int f, Node[] t, + Fun searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final Fun searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchValuesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply(p.val)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + break; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class SearchEntriesTask + extends BulkTask { + final Fun, ? extends U> searchFunction; + final AtomicReference result; + SearchEntriesTask + (BulkTask p, int b, int i, int f, Node[] t, + Fun, ? extends U> searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final Fun, ? extends U> searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchEntriesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply(p)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + return; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class SearchMappingsTask + extends BulkTask { + final BiFun searchFunction; + final AtomicReference result; + SearchMappingsTask + (BulkTask p, int b, int i, int f, Node[] t, + BiFun searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final BiFun searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchMappingsTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply(p.key, p.val)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + break; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class ReduceKeysTask + extends BulkTask { + final BiFun reducer; + K result; + ReduceKeysTask rights, nextRight; + ReduceKeysTask + (BulkTask p, int b, int i, int f, Node[] t, + ReduceKeysTask nextRight, + BiFun reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.reducer = reducer; + } + public final K getRawResult() { return result; } + public final void compute() { + final BiFun reducer; + if ((reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new ReduceKeysTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, reducer)).fork(); + } + K r = null; + for (Node p; (p = advance()) != null; ) { + K u = p.key; + r = (r == null) ? u : u == null ? r : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") ReduceKeysTask + t = (ReduceKeysTask)c, + s = t.rights; + while (s != null) { + K tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class ReduceValuesTask + extends BulkTask { + final BiFun reducer; + V result; + ReduceValuesTask rights, nextRight; + ReduceValuesTask + (BulkTask p, int b, int i, int f, Node[] t, + ReduceValuesTask nextRight, + BiFun reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.reducer = reducer; + } + public final V getRawResult() { return result; } + public final void compute() { + final BiFun reducer; + if ((reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new ReduceValuesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, reducer)).fork(); + } + V r = null; + for (Node p; (p = advance()) != null; ) { + V v = p.val; + r = (r == null) ? v : reducer.apply(r, v); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") ReduceValuesTask + t = (ReduceValuesTask)c, + s = t.rights; + while (s != null) { + V tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class ReduceEntriesTask + extends BulkTask> { + final BiFun, Map.Entry, ? extends Map.Entry> reducer; + Map.Entry result; + ReduceEntriesTask rights, nextRight; + ReduceEntriesTask + (BulkTask p, int b, int i, int f, Node[] t, + ReduceEntriesTask nextRight, + BiFun, Map.Entry, ? extends Map.Entry> reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.reducer = reducer; + } + public final Map.Entry getRawResult() { return result; } + public final void compute() { + final BiFun, Map.Entry, ? extends Map.Entry> reducer; + if ((reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new ReduceEntriesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, reducer)).fork(); + } + Map.Entry r = null; + for (Node p; (p = advance()) != null; ) + r = (r == null) ? p : reducer.apply(r, p); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") ReduceEntriesTask + t = (ReduceEntriesTask)c, + s = t.rights; + while (s != null) { + Map.Entry tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceKeysTask + extends BulkTask { + final Fun transformer; + final BiFun reducer; + U result; + MapReduceKeysTask rights, nextRight; + MapReduceKeysTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysTask nextRight, + Fun transformer, + BiFun reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final Fun transformer; + final BiFun reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.key)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceKeysTask + t = (MapReduceKeysTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceValuesTask + extends BulkTask { + final Fun transformer; + final BiFun reducer; + U result; + MapReduceValuesTask rights, nextRight; + MapReduceValuesTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesTask nextRight, + Fun transformer, + BiFun reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final Fun transformer; + final BiFun reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.val)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceValuesTask + t = (MapReduceValuesTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceEntriesTask + extends BulkTask { + final Fun, ? extends U> transformer; + final BiFun reducer; + U result; + MapReduceEntriesTask rights, nextRight; + MapReduceEntriesTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesTask nextRight, + Fun, ? extends U> transformer, + BiFun reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final Fun, ? extends U> transformer; + final BiFun reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceEntriesTask + t = (MapReduceEntriesTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceMappingsTask + extends BulkTask { + final BiFun transformer; + final BiFun reducer; + U result; + MapReduceMappingsTask rights, nextRight; + MapReduceMappingsTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsTask nextRight, + BiFun transformer, + BiFun reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final BiFun transformer; + final BiFun reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.key, p.val)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceMappingsTask + t = (MapReduceMappingsTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceKeysToDoubleTask + extends BulkTask { + final ObjectToDouble transformer; + final DoubleByDoubleToDouble reducer; + final double basis; + double result; + MapReduceKeysToDoubleTask rights, nextRight; + MapReduceKeysToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysToDoubleTask nextRight, + ObjectToDouble transformer, + double basis, + DoubleByDoubleToDouble reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ObjectToDouble transformer; + final DoubleByDoubleToDouble reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.key)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceKeysToDoubleTask + t = (MapReduceKeysToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceValuesToDoubleTask + extends BulkTask { + final ObjectToDouble transformer; + final DoubleByDoubleToDouble reducer; + final double basis; + double result; + MapReduceValuesToDoubleTask rights, nextRight; + MapReduceValuesToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesToDoubleTask nextRight, + ObjectToDouble transformer, + double basis, + DoubleByDoubleToDouble reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ObjectToDouble transformer; + final DoubleByDoubleToDouble reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceValuesToDoubleTask + t = (MapReduceValuesToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceEntriesToDoubleTask + extends BulkTask { + final ObjectToDouble> transformer; + final DoubleByDoubleToDouble reducer; + final double basis; + double result; + MapReduceEntriesToDoubleTask rights, nextRight; + MapReduceEntriesToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesToDoubleTask nextRight, + ObjectToDouble> transformer, + double basis, + DoubleByDoubleToDouble reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ObjectToDouble> transformer; + final DoubleByDoubleToDouble reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceEntriesToDoubleTask + t = (MapReduceEntriesToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceMappingsToDoubleTask + extends BulkTask { + final ObjectByObjectToDouble transformer; + final DoubleByDoubleToDouble reducer; + final double basis; + double result; + MapReduceMappingsToDoubleTask rights, nextRight; + MapReduceMappingsToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsToDoubleTask nextRight, + ObjectByObjectToDouble transformer, + double basis, + DoubleByDoubleToDouble reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ObjectByObjectToDouble transformer; + final DoubleByDoubleToDouble reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.key, p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceMappingsToDoubleTask + t = (MapReduceMappingsToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceKeysToLongTask + extends BulkTask { + final ObjectToLong transformer; + final LongByLongToLong reducer; + final long basis; + long result; + MapReduceKeysToLongTask rights, nextRight; + MapReduceKeysToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysToLongTask nextRight, + ObjectToLong transformer, + long basis, + LongByLongToLong reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ObjectToLong transformer; + final LongByLongToLong reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.key)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceKeysToLongTask + t = (MapReduceKeysToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceValuesToLongTask + extends BulkTask { + final ObjectToLong transformer; + final LongByLongToLong reducer; + final long basis; + long result; + MapReduceValuesToLongTask rights, nextRight; + MapReduceValuesToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesToLongTask nextRight, + ObjectToLong transformer, + long basis, + LongByLongToLong reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ObjectToLong transformer; + final LongByLongToLong reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceValuesToLongTask + t = (MapReduceValuesToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceEntriesToLongTask + extends BulkTask { + final ObjectToLong> transformer; + final LongByLongToLong reducer; + final long basis; + long result; + MapReduceEntriesToLongTask rights, nextRight; + MapReduceEntriesToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesToLongTask nextRight, + ObjectToLong> transformer, + long basis, + LongByLongToLong reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ObjectToLong> transformer; + final LongByLongToLong reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceEntriesToLongTask + t = (MapReduceEntriesToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceMappingsToLongTask + extends BulkTask { + final ObjectByObjectToLong transformer; + final LongByLongToLong reducer; + final long basis; + long result; + MapReduceMappingsToLongTask rights, nextRight; + MapReduceMappingsToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsToLongTask nextRight, + ObjectByObjectToLong transformer, + long basis, + LongByLongToLong reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ObjectByObjectToLong transformer; + final LongByLongToLong reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.key, p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceMappingsToLongTask + t = (MapReduceMappingsToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceKeysToIntTask + extends BulkTask { + final ObjectToInt transformer; + final IntByIntToInt reducer; + final int basis; + int result; + MapReduceKeysToIntTask rights, nextRight; + MapReduceKeysToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysToIntTask nextRight, + ObjectToInt transformer, + int basis, + IntByIntToInt reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ObjectToInt transformer; + final IntByIntToInt reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.key)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceKeysToIntTask + t = (MapReduceKeysToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceValuesToIntTask + extends BulkTask { + final ObjectToInt transformer; + final IntByIntToInt reducer; + final int basis; + int result; + MapReduceValuesToIntTask rights, nextRight; + MapReduceValuesToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesToIntTask nextRight, + ObjectToInt transformer, + int basis, + IntByIntToInt reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ObjectToInt transformer; + final IntByIntToInt reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceValuesToIntTask + t = (MapReduceValuesToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceEntriesToIntTask + extends BulkTask { + final ObjectToInt> transformer; + final IntByIntToInt reducer; + final int basis; + int result; + MapReduceEntriesToIntTask rights, nextRight; + MapReduceEntriesToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesToIntTask nextRight, + ObjectToInt> transformer, + int basis, + IntByIntToInt reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ObjectToInt> transformer; + final IntByIntToInt reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceEntriesToIntTask + t = (MapReduceEntriesToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + @SuppressWarnings("serial") + static final class MapReduceMappingsToIntTask + extends BulkTask { + final ObjectByObjectToInt transformer; + final IntByIntToInt reducer; + final int basis; + int result; + MapReduceMappingsToIntTask rights, nextRight; + MapReduceMappingsToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsToIntTask nextRight, + ObjectByObjectToInt transformer, + int basis, + IntByIntToInt reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ObjectByObjectToInt transformer; + final IntByIntToInt reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.apply(r, transformer.apply(p.key, p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + @SuppressWarnings("unchecked") MapReduceMappingsToIntTask + t = (MapReduceMappingsToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.apply(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + /* ---------------- Counters -------------- */ + + // Adapted from LongAdder and Striped64. + // See their internal docs for explanation. + + // A padded cell for distributing counts + static final class CounterCell { + volatile long p0, p1, p2, p3, p4, p5, p6; + volatile long value; + volatile long q0, q1, q2, q3, q4, q5, q6; + CounterCell(long x) { value = x; } } /** - * Saves the state of the {@code ConcurrentHashMapV8} instance to a - * stream (i.e., serializes it). - * @param s the stream - * @serialData - * the key (Object) and value (Object) - * for each key-value mapping, followed by a null pair. - * The key-value mappings are emitted in no particular order. + * Holder for the thread-local hash code determining which + * CounterCell to use. The code is initialized via the + * counterHashCodeGenerator, but may be moved upon collisions. */ - @SuppressWarnings("unchecked") - private void writeObject(java.io.ObjectOutputStream s) - throws java.io.IOException { - if (segments == null) { // for serialization compatibility - segments = (Segment[]) - new Segment[DEFAULT_CONCURRENCY_LEVEL]; - for (int i = 0; i < segments.length; ++i) - segments[i] = new Segment(LOAD_FACTOR); - } - s.defaultWriteObject(); - InternalIterator it = new InternalIterator(table); - while (it.next != null) { - s.writeObject(it.nextKey); - s.writeObject(it.nextVal); - it.advance(); - } - s.writeObject(null); - s.writeObject(null); - segments = null; // throw away + static final class CounterHashCode { + int code; } /** - * Reconstitutes the instance from a stream (that is, deserializes it). - * @param s the stream + * Generates initial value for per-thread CounterHashCodes. */ - @SuppressWarnings("unchecked") - private void readObject(java.io.ObjectInputStream s) - throws java.io.IOException, ClassNotFoundException { - s.defaultReadObject(); - this.segments = null; // unneeded - // initalize transient final field - UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder()); - this.targetCapacity = DEFAULT_CAPACITY; + static final AtomicInteger counterHashCodeGenerator = new AtomicInteger(); - // Create all nodes, then place in table once size is known - long size = 0L; - Node p = null; - for (;;) { - K k = (K) s.readObject(); - V v = (V) s.readObject(); - if (k != null && v != null) { - p = new Node(spread(k.hashCode()), k, v, p); - ++size; + /** + * Increment for counterHashCodeGenerator. See class ThreadLocal + * for explanation. + */ + static final int SEED_INCREMENT = 0x61c88647; + + /** + * Per-thread counter hash codes. Shared across all instances. + */ + static final ThreadLocal threadCounterHashCode = + new ThreadLocal(); + + + final long sumCount() { + CounterCell[] as = counterCells; CounterCell a; + long sum = baseCount; + if (as != null) { + for (int i = 0; i < as.length; ++i) { + if ((a = as[i]) != null) + sum += a.value; } - else - break; } - if (p != null) { - boolean init = false; - if (resizing == 0 && - UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { - try { - if (table == null) { - init = true; - int n; - if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) - n = MAXIMUM_CAPACITY; - else { - int sz = (int)size; - n = tableSizeFor(sz + (sz >>> 1) + 1); + return sum; + } + + // See LongAdder version for explanation + private final void fullAddCount(long x, CounterHashCode hc, + boolean wasUncontended) { + int h; + if (hc == null) { + hc = new CounterHashCode(); + int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT); + h = hc.code = (s == 0) ? 1 : s; // Avoid zero + threadCounterHashCode.set(hc); + } + else + h = hc.code; + boolean collide = false; // True if last slot nonempty + for (;;) { + CounterCell[] as; CounterCell a; int n; long v; + if ((as = counterCells) != null && (n = as.length) > 0) { + if ((a = as[(n - 1) & h]) == null) { + if (cellsBusy == 0) { // Try to attach new Cell + CounterCell r = new CounterCell(x); // Optimistic create + if (cellsBusy == 0 && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + boolean created = false; + try { // Recheck under lock + CounterCell[] rs; int m, j; + if ((rs = counterCells) != null && + (m = rs.length) > 0 && + rs[j = (m - 1) & h] == null) { + rs[j] = r; + created = true; + } + } finally { + cellsBusy = 0; + } + if (created) + break; + continue; // Slot is now non-empty } - threshold = n - (n >>> 2) - THRESHOLD_OFFSET; - Node[] tab = new Node[n]; - int mask = n - 1; - while (p != null) { - int j = p.hash & mask; - Node next = p.next; - p.next = tabAt(tab, j); - setTabAt(tab, j, p); - p = next; + } + collide = false; + } + else if (!wasUncontended) // CAS already known to fail + wasUncontended = true; // Continue after rehash + else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x)) + break; + else if (counterCells != as || n >= NCPU) + collide = false; // At max size or stale + else if (!collide) + collide = true; + else if (cellsBusy == 0 && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + try { + if (counterCells == as) {// Expand table unless stale + CounterCell[] rs = new CounterCell[n << 1]; + for (int i = 0; i < n; ++i) + rs[i] = as[i]; + counterCells = rs; } - table = tab; - counter.add(size); + } finally { + cellsBusy = 0; } - } finally { - resizing = 0; + collide = false; + continue; // Retry with expanded table } + h ^= h << 13; // Rehash + h ^= h >>> 17; + h ^= h << 5; } - if (!init) { // Can only happen if unsafely published. - while (p != null) { - internalPut(p.key, p.val, true); - p = p.next; + else if (cellsBusy == 0 && counterCells == as && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + boolean init = false; + try { // Initialize table + if (counterCells == as) { + CounterCell[] rs = new CounterCell[2]; + rs[h & 1] = new CounterCell(x); + counterCells = rs; + init = true; + } + } finally { + cellsBusy = 0; } + if (init) + break; } + else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x)) + break; // Fall back on using base } + hc.code = h; // Record index for next time } // Unsafe mechanics - private static final sun.misc.Unsafe UNSAFE; - private static final long counterOffset; - private static final long resizingOffset; + private static final sun.misc.Unsafe U; + private static final long SIZECTL; + private static final long TRANSFERINDEX; + private static final long TRANSFERORIGIN; + private static final long BASECOUNT; + private static final long CELLSBUSY; + private static final long CELLVALUE; private static final long ABASE; private static final int ASHIFT; static { - int ss; try { - UNSAFE = getUnsafe(); + U = getUnsafe(); Class k = ConcurrentHashMapV8.class; - counterOffset = UNSAFE.objectFieldOffset - (k.getDeclaredField("counter")); - resizingOffset = UNSAFE.objectFieldOffset - (k.getDeclaredField("resizing")); - Class sc = Node[].class; - ABASE = UNSAFE.arrayBaseOffset(sc); - ss = UNSAFE.arrayIndexScale(sc); + SIZECTL = U.objectFieldOffset + (k.getDeclaredField("sizeCtl")); + TRANSFERINDEX = U.objectFieldOffset + (k.getDeclaredField("transferIndex")); + TRANSFERORIGIN = U.objectFieldOffset + (k.getDeclaredField("transferOrigin")); + BASECOUNT = U.objectFieldOffset + (k.getDeclaredField("baseCount")); + CELLSBUSY = U.objectFieldOffset + (k.getDeclaredField("cellsBusy")); + Class ck = CounterCell.class; + CELLVALUE = U.objectFieldOffset + (ck.getDeclaredField("value")); + Class ak = Node[].class; + ABASE = U.arrayBaseOffset(ak); + int scale = U.arrayIndexScale(ak); + if ((scale & (scale - 1)) != 0) + throw new Error("data type scale not a power of two"); + ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); } catch (Exception e) { throw new Error(e); } - if ((ss & (ss-1)) != 0) - throw new Error("data type scale not a power of two"); - ASHIFT = 31 - Integer.numberOfLeadingZeros(ss); } /** @@ -1718,22 +6171,23 @@ public class ConcurrentHashMapV8 private static sun.misc.Unsafe getUnsafe() { try { return sun.misc.Unsafe.getUnsafe(); - } catch (SecurityException se) { - try { - return java.security.AccessController.doPrivileged - (new java.security - .PrivilegedExceptionAction() { - public sun.misc.Unsafe run() throws Exception { - java.lang.reflect.Field f = sun.misc - .Unsafe.class.getDeclaredField("theUnsafe"); - f.setAccessible(true); - return (sun.misc.Unsafe) f.get(null); - }}); - } catch (java.security.PrivilegedActionException e) { - throw new RuntimeException("Could not initialize intrinsics", - e.getCause()); - } + } catch (SecurityException tryReflectionInstead) {} + try { + return java.security.AccessController.doPrivileged + (new java.security.PrivilegedExceptionAction() { + public sun.misc.Unsafe run() throws Exception { + Class k = sun.misc.Unsafe.class; + for (java.lang.reflect.Field f : k.getDeclaredFields()) { + f.setAccessible(true); + Object x = f.get(null); + if (k.isInstance(x)) + return k.cast(x); + } + throw new NoSuchFieldError("the Unsafe"); + }}); + } catch (java.security.PrivilegedActionException e) { + throw new RuntimeException("Could not initialize intrinsics", + e.getCause()); } } - }