--- jsr166/src/jsr166e/ConcurrentHashMapV8.java 2012/07/06 21:39:18 1.48
+++ jsr166/src/jsr166e/ConcurrentHashMapV8.java 2012/11/24 03:46:28 1.80
@@ -5,7 +5,30 @@
*/
package jsr166e;
-import jsr166e.LongAdder;
+
+import java.util.Comparator;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.Set;
+import java.util.Collection;
+import java.util.AbstractMap;
+import java.util.AbstractSet;
+import java.util.AbstractCollection;
+import java.util.Hashtable;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Enumeration;
+import java.util.ConcurrentModificationException;
+import java.util.NoSuchElementException;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.locks.LockSupport;
+import java.util.concurrent.locks.AbstractQueuedSynchronizer;
+import java.util.concurrent.atomic.AtomicReference;
+
+import java.io.Serializable;
+
+import java.util.Comparator;
import java.util.Arrays;
import java.util.Map;
import java.util.Set;
@@ -23,6 +46,8 @@ import java.util.concurrent.ConcurrentMa
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.locks.LockSupport;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
+import java.util.concurrent.atomic.AtomicReference;
+
import java.io.Serializable;
/**
@@ -37,25 +62,28 @@ 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 (corresponding
@@ -76,68 +104,150 @@ import java.io.Serializable;
* {@code hashCode()} is a sure way to slow down performance of any
* hash table.
*
+ *
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.
+ *
+ *
A ConcurrentHashMapV8 can be used as scalable frequency map (a
+ * form of histogram or multiset) by using {@link LongAdder} values
+ * and initializing via {@link #computeIfAbsent}. For example, to add
+ * a count to a {@code ConcurrentHashMapV8 freqs}, you
+ * can use {@code freqs.computeIfAbsent(k -> new
+ * LongAdder()).increment();}
+ *
* 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 parallel operations using the {@link
+ * ForkJoinPool#commonPool}. (Tasks that may be used in other contexts
+ * are available in class {@link ForkJoinTasks}). These operations 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. (The first three forms are
+ * also available via the {@link #keySet()}, {@link #values()} and
+ * {@link #entrySet()} views). 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.
+ *
+ *
+ * - forEach: Perform a given action on each element.
+ * A variant form applies a given transformation on each element
+ * before performing the action.
+ *
+ * - search: Return the first available non-null result of
+ * applying a given function on each element; skipping further
+ * search when a result is found.
+ *
+ * - reduce: Accumulate each element. The supplied reduction
+ * function cannot rely on ordering (more formally, it should be
+ * both associative and commutative). There are five variants:
+ *
+ *
+ *
+ * - Plain reductions. (There is not a form of this method for
+ * (key, value) function arguments since there is no corresponding
+ * return type.)
+ *
+ * - Mapped reductions that accumulate the results of a given
+ * function applied to each element.
+ *
+ * - Reductions to scalar doubles, longs, and ints, using a
+ * given basis value.
+ *
+ *
+ *
+ *
+ *
+ * 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.
+ *
+ *
Parallel speedups for bulk operations compared to sequential
+ * processing are common but not guaranteed. Operations involving
+ * brief functions on small maps may execute more slowly than
+ * sequential loops 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 {
+ implements ConcurrentMap, Serializable {
private static final long serialVersionUID = 7249069246763182397L;
/**
- * A function computing a mapping from the given key to a value.
- * 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.
- *
- * @param key the (non-null) key
- * @return a value for the key, or null if none
- */
- V map(K key);
- }
-
- /**
- * A function computing a new mapping given a key and its current
- * mapped value (or {@code null} if there is no current
- * mapping). This is a place-holder for an upcoming JDK8
- * interface.
- */
- public static interface RemappingFunction {
- /**
- * Returns a new value given a key and its current value.
- *
- * @param key the (non-null) key
- * @param value the current value, or null if there is no mapping
- * @return a value for the key, or null if none
- */
- V remap(K key, V value);
- }
-
- /**
* A partitionable iterator. A Spliterator can be traversed
* directly, but can also be partitioned (before traversal) by
* creating another Spliterator that covers a non-overlapping
* portion of the elements, and so may be amenable to parallel
* execution.
*
- * This interface exports a subset of expected JDK8
+ *
This interface exports a subset of expected JDK8
* functionality.
*
*
Sample usage: Here is one (of the several) ways to compute
@@ -150,13 +260,15 @@ public class ConcurrentHashMapV8
*
*
* {@code ConcurrentHashMapV8 m = ...
- * // Uses parallel depth of log2 of size / (parallelism * slack of 8).
- * int depth = 32 - Integer.numberOfLeadingZeros(m.size() / (aForkJoinPool.getParallelism() * 8));
- * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), depth, null));
+ * // split as if have 8 * parallelism, for load balance
+ * int n = m.size();
+ * int p = aForkJoinPool.getParallelism() * 8;
+ * int split = (n < p)? n : p;
+ * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
* // ...
* static class SumValues extends RecursiveTask {
* final Spliterator s;
- * final int depth; // number of splits before processing
+ * final int split; // split while > 1
* final SumValues nextJoin; // records forked subtasks to join
* SumValues(Spliterator s, int depth, SumValues nextJoin) {
* this.s = s; this.depth = depth; this.nextJoin = nextJoin;
@@ -164,8 +276,8 @@ public class ConcurrentHashMapV8
* public Long compute() {
* long sum = 0;
* SumValues subtasks = null; // fork subtasks
- * for (int d = depth - 1; d >= 0; --d)
- * (subtasks = new SumValues(s.split(), d, subtasks)).fork();
+ * for (int s = split >>> 1; s > 0; s >>>= 1)
+ * (subtasks = new SumValues(s.split(), s, subtasks)).fork();
* while (s.hasNext()) // directly process remaining elements
* sum += s.next();
* for (SumValues t = subtasks; t != null; t = t.nextJoin)
@@ -197,6 +309,7 @@ public class ConcurrentHashMapV8
Spliterator split();
}
+
/*
* Overview:
*
@@ -348,7 +461,7 @@ public class ConcurrentHashMapV8
* When there are no lock acquisition failures, this is arranged
* simply by proceeding 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
+ * (see class Iter) arrange to move to the new table
* without revisiting nodes. However, when any node is skipped
* during a transfer, all earlier table bins may have become
* visible, so are initialized with a reverse-forwarding node back
@@ -358,7 +471,7 @@ public class ConcurrentHashMapV8
* mechanics trigger only when necessary.
*
* The traversal scheme also applies to partial traversals of
- * ranges of bins (via an alternate InternalIterator constructor)
+ * 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
@@ -479,9 +592,9 @@ public class ConcurrentHashMapV8
private transient volatile int sizeCtl;
// views
- private transient KeySet keySet;
- private transient Values values;
- private transient EntrySet entrySet;
+ private transient KeySetView keySet;
+ private transient ValuesView values;
+ private transient EntrySetView entrySet;
/** For serialization compatibility. Null unless serialized; see below */
private Segment[] segments;
@@ -500,7 +613,7 @@ public class ConcurrentHashMapV8
* inline assignments below.
*/
- static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
+ static final Node tabAt(Node[] tab, int i) { // used by Iter
return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<
* unlocking lock (via a failed CAS from non-waiting LOCKED
* state), unlockers acquire the sync lock and perform a
* notifyAll.
+ *
+ * The initial sanity check on tab and bounds is not currently
+ * necessary in the only usages of this method, but enables
+ * use in other future contexts.
*/
final void tryAwaitLock(Node[] tab, int i) {
- if (tab != null && i >= 0 && i < tab.length) { // bounds check
+ if (tab != null && i >= 0 && i < tab.length) { // sanity check
int r = ThreadLocalRandom.current().nextInt(); // randomize spins
int spins = MAX_SPINS, h;
while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
@@ -576,7 +693,10 @@ public class ConcurrentHashMapV8
try {
wait();
} catch (InterruptedException ie) {
- Thread.currentThread().interrupt();
+ try {
+ Thread.currentThread().interrupt();
+ } catch (SecurityException ignore) {
+ }
}
}
else
@@ -648,7 +768,7 @@ public class ConcurrentHashMapV8
* TreeBins also maintain a separate locking discipline than
* regular bins. Because they are forwarded via special MOVED
* nodes at bin heads (which can never change once established),
- * we cannot use use those nodes as locks. Instead, TreeBin
+ * we cannot use those nodes as locks. Instead, TreeBin
* extends AbstractQueuedSynchronizer to support a simple form of
* read-write lock. For update operations and table validation,
* the exclusive form of lock behaves in the same way as bin-head
@@ -733,11 +853,11 @@ public class ConcurrentHashMapV8
}
/**
- * Return the TreeNode (or null if not found) for the given key
+ * Returns the TreeNode (or null if not found) for the given key
* starting at given root.
*/
- @SuppressWarnings("unchecked") // suppress Comparable cast warning
- final TreeNode getTreeNode(int h, Object k, TreeNode p) {
+ @SuppressWarnings("unchecked") final TreeNode getTreeNode
+ (int h, Object k, TreeNode p) {
Class c = k.getClass();
while (p != null) {
int dir, ph; Object pk; Class pc;
@@ -797,8 +917,8 @@ public class ConcurrentHashMapV8
* Finds or adds a node.
* @return null if added
*/
- @SuppressWarnings("unchecked") // suppress Comparable cast warning
- final TreeNode putTreeNode(int h, Object k, Object v) {
+ @SuppressWarnings("unchecked") final TreeNode putTreeNode
+ (int h, Object k, Object v) {
Class c = k.getClass();
TreeNode pp = root, p = null;
int dir = 0;
@@ -1225,7 +1345,7 @@ public class ConcurrentHashMapV8
}
/*
- * Internal versions of the five insertion methods, each a
+ * Internal versions of the six insertion methods, each a
* little more complicated than the last. All have
* the same basic structure as the first (internalPut):
* 1. If table uninitialized, create
@@ -1243,6 +1363,8 @@ public class ConcurrentHashMapV8
* returns from function call.
* * compute uses the same function-call mechanics, but without
* the prescans
+ * * merge acts as putIfAbsent in the absent case, but invokes the
+ * update function if present
* * putAll attempts to pre-allocate enough table space
* and more lazily performs count updates and checks.
*
@@ -1439,7 +1561,7 @@ public class ConcurrentHashMapV8
/** Implementation for computeIfAbsent */
private final Object internalComputeIfAbsent(K k,
- MappingFunction mf) {
+ Fun mf) {
int h = spread(k.hashCode());
Object val = null;
int count = 0;
@@ -1452,7 +1574,7 @@ public class ConcurrentHashMapV8
if (casTabAt(tab, i, null, node)) {
count = 1;
try {
- if ((val = mf.map(k)) != null)
+ if ((val = mf.apply(k)) != null)
node.val = val;
} finally {
if (val == null)
@@ -1477,7 +1599,7 @@ public class ConcurrentHashMapV8
TreeNode p = t.getTreeNode(h, k, t.root);
if (p != null)
val = p.val;
- else if ((val = mf.map(k)) != null) {
+ else if ((val = mf.apply(k)) != null) {
added = true;
count = 2;
t.putTreeNode(h, k, val);
@@ -1531,7 +1653,7 @@ public class ConcurrentHashMapV8
}
Node last = e;
if ((e = e.next) == null) {
- if ((val = mf.map(k)) != null) {
+ if ((val = mf.apply(k)) != null) {
added = true;
last.next = new Node(h, k, val, null);
if (count >= TREE_THRESHOLD)
@@ -1566,9 +1688,8 @@ public class ConcurrentHashMapV8
}
/** Implementation for compute */
- @SuppressWarnings("unchecked")
- private final Object internalCompute(K k,
- RemappingFunction mf) {
+ @SuppressWarnings("unchecked") private final Object internalCompute
+ (K k, boolean onlyIfPresent, BiFun mf) {
int h = spread(k.hashCode());
Object val = null;
int delta = 0;
@@ -1578,11 +1699,13 @@ public class ConcurrentHashMapV8
if (tab == null)
tab = initTable();
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
+ if (onlyIfPresent)
+ break;
Node node = new Node(fh = h | LOCKED, k, null, null);
if (casTabAt(tab, i, null, node)) {
try {
count = 1;
- if ((val = mf.remap(k, null)) != null) {
+ if ((val = mf.apply(k, null)) != null) {
node.val = val;
delta = 1;
}
@@ -1607,7 +1730,7 @@ public class ConcurrentHashMapV8
count = 1;
TreeNode p = t.getTreeNode(h, k, t.root);
Object pv = (p == null) ? null : p.val;
- if ((val = mf.remap(k, (V)pv)) != null) {
+ if ((val = mf.apply(k, (V)pv)) != null) {
if (p != null)
p.val = val;
else {
@@ -1643,7 +1766,7 @@ public class ConcurrentHashMapV8
if ((e.hash & HASH_BITS) == h &&
(ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek))) {
- val = mf.remap(k, (V)ev);
+ val = mf.apply(k, (V)ev);
if (val != null)
e.val = val;
else {
@@ -1658,7 +1781,7 @@ public class ConcurrentHashMapV8
}
pred = e;
if ((e = e.next) == null) {
- if ((val = mf.remap(k, null)) != null) {
+ if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
pred.next = new Node(h, k, val, null);
delta = 1;
if (count >= TREE_THRESHOLD)
@@ -1689,6 +1812,114 @@ public class ConcurrentHashMapV8
return val;
}
+ /** Implementation for merge */
+ @SuppressWarnings("unchecked") private final Object internalMerge
+ (K k, V v, BiFun mf) {
+ int h = spread(k.hashCode());
+ Object val = null;
+ int delta = 0;
+ int count = 0;
+ for (Node[] tab = table;;) {
+ int i; Node f; int fh; Object fk, fv;
+ if (tab == null)
+ tab = initTable();
+ else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
+ if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
+ delta = 1;
+ val = v;
+ break;
+ }
+ }
+ else if ((fh = f.hash) == MOVED) {
+ if ((fk = f.key) instanceof TreeBin) {
+ TreeBin t = (TreeBin)fk;
+ t.acquire(0);
+ try {
+ if (tabAt(tab, i) == f) {
+ count = 1;
+ TreeNode p = t.getTreeNode(h, k, t.root);
+ val = (p == null) ? v : mf.apply((V)p.val, v);
+ if (val != null) {
+ if (p != null)
+ p.val = val;
+ else {
+ count = 2;
+ delta = 1;
+ t.putTreeNode(h, k, val);
+ }
+ }
+ else if (p != null) {
+ delta = -1;
+ t.deleteTreeNode(p);
+ }
+ }
+ } finally {
+ t.release(0);
+ }
+ if (count != 0)
+ break;
+ }
+ else
+ tab = (Node[])fk;
+ }
+ else if ((fh & LOCKED) != 0) {
+ checkForResize();
+ f.tryAwaitLock(tab, i);
+ }
+ else if (f.casHash(fh, fh | LOCKED)) {
+ try {
+ if (tabAt(tab, i) == f) {
+ count = 1;
+ for (Node e = f, pred = null;; ++count) {
+ Object ek, ev;
+ if ((e.hash & HASH_BITS) == h &&
+ (ev = e.val) != null &&
+ ((ek = e.key) == k || k.equals(ek))) {
+ val = mf.apply(v, (V)ev);
+ 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 = v;
+ pred.next = new Node(h, k, val, null);
+ delta = 1;
+ if (count >= TREE_THRESHOLD)
+ replaceWithTreeBin(tab, i, k);
+ break;
+ }
+ }
+ }
+ } finally {
+ if (!f.casHash(fh | LOCKED, fh)) {
+ f.hash = fh;
+ synchronized (f) { f.notifyAll(); };
+ }
+ }
+ if (count != 0) {
+ if (tab.length <= 64)
+ count = 2;
+ break;
+ }
+ }
+ }
+ if (delta != 0) {
+ counter.add((long)delta);
+ if (count > 1)
+ checkForResize();
+ }
+ return val;
+ }
+
/** Implementation for putAll */
private final void internalPutAll(Map m) {
tryPresize(m.size());
@@ -1913,7 +2144,7 @@ public class ConcurrentHashMapV8
for (int i = bin;;) { // start upwards sweep
int fh; Node f;
if ((f = tabAt(tab, i)) == null) {
- if (bin >= 0) { // no lock needed (or available)
+ if (bin >= 0) { // Unbuffered; no lock needed (or available)
if (!casTabAt(tab, i, f, fwd))
continue;
}
@@ -2089,8 +2320,10 @@ public class ConcurrentHashMapV8
try {
if (tabAt(tab, i) == f) {
for (Node p = t.first; p != null; p = p.next) {
- p.val = null;
- --delta;
+ if (p.val != null) { // (currently always true)
+ p.val = null;
+ --delta;
+ }
}
t.first = null;
t.root = null;
@@ -2112,8 +2345,10 @@ public class ConcurrentHashMapV8
try {
if (tabAt(tab, i) == f) {
for (Node e = f; e != null; e = e.next) {
- e.val = null;
- --delta;
+ if (e.val != null) { // (currently always true)
+ e.val = null;
+ --delta;
+ }
}
setTabAt(tab, i, null);
++i;
@@ -2134,7 +2369,7 @@ public class ConcurrentHashMapV8
/**
* Encapsulates traversal for methods such as containsValue; also
- * serves as a base class for other iterators.
+ * serves as a base class for other iterators and bulk tasks.
*
* At each step, the iterator snapshots the key ("nextKey") and
* value ("nextVal") of a valid node (i.e., one that, at point of
@@ -2142,7 +2377,8 @@ public class ConcurrentHashMapV8
* 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.
+ * valid. To support iterator.remove, the nextKey field is not
+ * updated (nulled out) when the iterator cannot advance.
*
* Internal traversals directly access these fields, as in:
* {@code while (it.advance() != null) { process(it.nextKey); }}
@@ -2168,34 +2404,46 @@ public class ConcurrentHashMapV8
* paranoically cope with potential sharing by users of iterators
* across threads, iteration terminates if a bounds checks fails
* for a table read.
+ *
+ * This class extends CountedCompleter to streamline parallel
+ * iteration in bulk operations. This adds only a few fields of
+ * space overhead, which is small enough in cases where it is not
+ * needed to not worry about it. Because CountedCompleter is
+ * Serializable, but iterators need not be, we need to add warning
+ * suppressions.
*/
- static class InternalIterator {
+ @SuppressWarnings("serial") static class Traverser extends CountedCompleter {
final ConcurrentHashMapV8 map;
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
int baseLimit; // index bound for initial table
- final int baseSize; // initial table size
+ int baseSize; // initial table size
+ int batch; // split control
/** Creates iterator for all entries in the table. */
- InternalIterator(ConcurrentHashMapV8 map) {
- this.tab = (this.map = map).table;
- baseLimit = baseSize = (tab == null) ? 0 : tab.length;
+ Traverser(ConcurrentHashMapV8 map) {
+ this.map = map;
}
- /** Creates iterator for clone() and split() methods. */
- InternalIterator(InternalIterator it, boolean split) {
- this.map = it.map;
- this.tab = it.tab;
- this.baseSize = it.baseSize;
- int lo = it.baseIndex;
- int hi = this.baseLimit = it.baseLimit;
- this.index = this.baseIndex =
- (split) ? (it.baseLimit = (lo + hi + 1) >>> 1) : lo;
+ /** Creates iterator for split() methods and task constructors */
+ Traverser(ConcurrentHashMapV8 map, Traverser it, int batch) {
+ super(it);
+ this.batch = batch;
+ if ((this.map = map) != null && it != null) { // split parent
+ Node[] t;
+ if ((t = it.tab) == null &&
+ (t = it.tab = map.table) != null)
+ it.baseLimit = it.baseSize = t.length;
+ this.tab = t;
+ this.baseSize = it.baseSize;
+ int hi = this.baseLimit = it.baseLimit;
+ it.baseLimit = this.index = this.baseIndex =
+ (hi + it.baseIndex + 1) >>> 1;
+ }
}
/**
@@ -2203,17 +2451,24 @@ public class ConcurrentHashMapV8
* See above for explanation.
*/
final Object advance() {
- Node e = last = next;
+ Node e = next;
Object ev = null;
outer: do {
if (e != null) // advance past used/skipped node
e = e.next;
while (e == null) { // get to next non-null bin
+ ConcurrentHashMapV8 m;
Node[] t; int b, i, n; Object ek; // checks must use locals
- if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
- (t = tab) == null || i >= (n = t.length))
+ if ((t = tab) != null)
+ n = t.length;
+ else if ((m = map) != null && (t = tab = m.table) != null)
+ n = baseLimit = baseSize = t.length;
+ else
+ break outer;
+ if ((b = baseIndex) >= baseLimit ||
+ (i = index) < 0 || i >= n)
break outer;
- else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
+ if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
if ((ek = e.key) instanceof TreeBin)
e = ((TreeBin)ek).first;
else {
@@ -2230,13 +2485,10 @@ public class ConcurrentHashMapV8
}
public final void remove() {
- if (nextVal == null)
- advance();
- Node e = last;
- if (e == null)
+ Object k = nextKey;
+ if (k == null && (advance() == null || (k = nextKey) == null))
throw new IllegalStateException();
- last = null;
- map.remove(e.key);
+ map.internalReplace(k, null, null);
}
public final boolean hasNext() {
@@ -2244,6 +2496,39 @@ public class ConcurrentHashMapV8
}
public final boolean hasMoreElements() { return hasNext(); }
+
+ public void compute() { } // default no-op CountedCompleter body
+
+ /**
+ * Returns a batch value > 0 if this task should (and must) be
+ * split, if so, adding to pending count, and in any case
+ * updating batch value. The initial batch value is approx
+ * 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 preSplit() {
+ ConcurrentHashMapV8 m; int b; Node[] t; ForkJoinPool pool;
+ if ((b = batch) < 0 && (m = map) != null) { // force initialization
+ if ((t = tab) == null && (t = tab = m.table) != null)
+ baseLimit = baseSize = t.length;
+ if (t != null) {
+ long n = m.counter.sum();
+ int par = ((pool = getPool()) == null) ?
+ ForkJoinPool.getCommonPoolParallelism() :
+ pool.getParallelism();
+ int sp = par << 3; // slack of 8
+ b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
+ }
+ }
+ b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
+ if ((batch = b) > 0)
+ addToPendingCount(1);
+ return b;
+ }
+
}
/* ---------------- Public operations -------------- */
@@ -2330,13 +2615,39 @@ public class ConcurrentHashMapV8
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));
+ int cap = (size >= (long)MAXIMUM_CAPACITY) ?
+ MAXIMUM_CAPACITY : tableSizeFor((int)size);
this.counter = new LongAdder();
this.sizeCtl = cap;
}
/**
+ * Creates a new {@link Set} backed by a ConcurrentHashMapV8
+ * from the given type to {@code Boolean.TRUE}.
+ *
+ * @return the new set
+ */
+ 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.
+ * @throws IllegalArgumentException if the initial capacity of
+ * elements is negative
+ * @return the new set
+ */
+ public static KeySetView newKeySet(int initialCapacity) {
+ return new KeySetView(new ConcurrentHashMapV8(initialCapacity),
+ Boolean.TRUE);
+ }
+
+ /**
* {@inheritDoc}
*/
public boolean isEmpty() {
@@ -2353,9 +2664,18 @@ public class ConcurrentHashMapV8
(int)n);
}
- final long longSize() { // accurate version of size needed for views
+ /**
+ * 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
+ */
+ public long mappingCount() {
long n = counter.sum();
- return (n < 0L) ? 0L : n;
+ return (n < 0L) ? 0L : n; // ignore transient negative values
}
/**
@@ -2369,14 +2689,30 @@ public class ConcurrentHashMapV8
*
* @throws NullPointerException if the specified key is null
*/
- @SuppressWarnings("unchecked")
- public V get(Object key) {
+ @SuppressWarnings("unchecked") public V get(Object key) {
if (key == null)
throw new NullPointerException();
return (V)internalGet(key);
}
/**
+ * Returns the value to which the specified key is mapped,
+ * or the given defaultValue if this map contains no mapping for the key.
+ *
+ * @param key the key
+ * @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 defaultValue
+ * @throws NullPointerException if the specified key is null
+ */
+ @SuppressWarnings("unchecked") public V getValueOrDefault(Object key, V defaultValue) {
+ if (key == null)
+ throw new NullPointerException();
+ V v = (V) internalGet(key);
+ return v == null ? defaultValue : v;
+ }
+
+ /**
* Tests if the specified object is a key in this table.
*
* @param key possible key
@@ -2405,7 +2741,7 @@ public class ConcurrentHashMapV8
if (value == null)
throw new NullPointerException();
Object v;
- InternalIterator it = new InternalIterator(this);
+ Traverser it = new Traverser(this);
while ((v = it.advance()) != null) {
if (v == value || value.equals(v))
return true;
@@ -2436,7 +2772,7 @@ public class ConcurrentHashMapV8
* 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
@@ -2445,8 +2781,7 @@ 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) {
+ @SuppressWarnings("unchecked") public V put(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return (V)internalPut(key, value);
@@ -2459,8 +2794,7 @@ public class ConcurrentHashMapV8
* 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) {
+ @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return (V)internalPutIfAbsent(key, value);
@@ -2484,7 +2818,7 @@ public class ConcurrentHashMapV8
* {@code
* if (map.containsKey(key))
* return map.get(key);
- * value = mappingFunction.map(key);
+ * value = mappingFunction.apply(key);
* if (value != null)
* map.put(key, value);
* return value;}
@@ -2501,13 +2835,13 @@ public class ConcurrentHashMapV8
* memoized result, as in:
*
* {@code
- * map.computeIfAbsent(key, new MappingFunction() {
+ * map.computeIfAbsent(key, new Fun() {
* 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 null if the computed value is null.
+ * 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
@@ -2516,19 +2850,60 @@ public class ConcurrentHashMapV8
* @throws RuntimeException or Error if the mappingFunction does so,
* in which case the mapping is left unestablished
*/
- @SuppressWarnings("unchecked")
- public V computeIfAbsent(K key, MappingFunction mappingFunction) {
+ @SuppressWarnings("unchecked") public V computeIfAbsent
+ (K key, Fun mappingFunction) {
if (key == null || mappingFunction == null)
throw new NullPointerException();
return (V)internalComputeIfAbsent(key, mappingFunction);
}
/**
+ * If the given key is present, computes a new mapping value given a key and
+ * its current mapped value. This is equivalent to
+ * {@code
+ * if (map.containsKey(key)) {
+ * value = remappingFunction.apply(key, map.get(key));
+ * if (value != null)
+ * map.put(key, value);
+ * else
+ * map.remove(key);
+ * }
+ * }
+ *
+ * except that the action is performed atomically. If the
+ * function returns {@code null}, the mapping is removed. If the
+ * function itself throws an (unchecked) exception, the exception
+ * is rethrown to its caller, and the current mapping is left
+ * unchanged. 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. For example,
+ * to either create or append new messages to a value mapping:
+ *
+ * @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
+ */
+ @SuppressWarnings("unchecked") public V computeIfPresent
+ (K key, BiFun remappingFunction) {
+ if (key == null || remappingFunction == null)
+ throw new NullPointerException();
+ return (V)internalCompute(key, true, remappingFunction);
+ }
+
+ /**
* Computes a new mapping value given a key and
* its current mapped value (or {@code null} if there is no current
* mapping). This is equivalent to
* {@code
- * value = remappingFunction.remap(key, map.get(key));
+ * value = remappingFunction.apply(key, map.get(key));
* if (value != null)
* map.put(key, value);
* else
@@ -2548,14 +2923,13 @@ public class ConcurrentHashMapV8
* {@code
* Map map = ...;
* final String msg = ...;
- * map.compute(key, new RemappingFunction() {
- * public String remap(Key k, String v) {
+ * map.compute(key, new BiFun() {
+ * public String apply(Key k, String v) {
* return (v == null) ? msg : v + msg;});}}
*
* @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.
+ * @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
@@ -2564,11 +2938,43 @@ public class ConcurrentHashMapV8
* @throws RuntimeException or Error if the remappingFunction does so,
* in which case the mapping is unchanged
*/
- @SuppressWarnings("unchecked")
- public V compute(K key, RemappingFunction remappingFunction) {
+ @SuppressWarnings("unchecked") public V compute
+ (K key, BiFun remappingFunction) {
if (key == null || remappingFunction == null)
throw new NullPointerException();
- return (V)internalCompute(key, remappingFunction);
+ return (V)internalCompute(key, false, remappingFunction);
+ }
+
+ /**
+ * If the specified key is not already associated
+ * with a value, associate it with the given value.
+ * Otherwise, replace the value with the results of
+ * the given remapping function. This is equivalent to:
+ * {@code
+ * if (!map.containsKey(key))
+ * map.put(value);
+ * else {
+ * newValue = remappingFunction.apply(map.get(key), value);
+ * if (value != null)
+ * map.put(key, value);
+ * else
+ * map.remove(key);
+ * }
+ * }
+ * except that the action is performed atomically. If the
+ * function returns {@code null}, the mapping is removed. If the
+ * function itself throws an (unchecked) exception, the exception
+ * is rethrown to its caller, and the current mapping is left
+ * unchanged. 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.
+ */
+ @SuppressWarnings("unchecked") public V merge
+ (K key, V value, BiFun remappingFunction) {
+ if (key == null || value == null || remappingFunction == null)
+ throw new NullPointerException();
+ return (V)internalMerge(key, value, remappingFunction);
}
/**
@@ -2580,8 +2986,7 @@ 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) {
+ @SuppressWarnings("unchecked") public V remove(Object key) {
if (key == null)
throw new NullPointerException();
return (V)internalReplace(key, null, null);
@@ -2618,8 +3023,7 @@ public class ConcurrentHashMapV8
* 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 replace(K key, V value) {
+ @SuppressWarnings("unchecked") public V replace(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return (V)internalReplace(key, value, null);
@@ -2635,43 +3039,41 @@ public class ConcurrentHashMapV8
/**
* 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
- * removal, which removes the corresponding mapping from this 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.
+ * reflected in the set, and vice-versa.
*
- * 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.
+ * @return the set view
+ */
+ public KeySetView keySet() {
+ KeySetView ks = keySet;
+ return (ks != null) ? ks : (keySet = new KeySetView(this, null));
+ }
+
+ /**
+ * 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}). 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 Set keySet() {
- KeySet ks = keySet;
- return (ks != null) ? ks : (keySet = new KeySet(this));
+ public KeySetView keySet(V mappedValue) {
+ if (mappedValue == null)
+ throw new NullPointerException();
+ return new KeySetView(this, mappedValue);
}
/**
* Returns a {@link Collection} view of the values contained in this map.
* The collection is backed by the map, so changes to the map are
- * reflected in the collection, and vice-versa. The collection
- * supports element removal, which removes the corresponding
- * mapping from this map, via the {@code Iterator.remove},
- * {@code Collection.remove}, {@code removeAll},
- * {@code retainAll}, and {@code clear} operations. It does not
- * support the {@code add} or {@code addAll} 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.
+ * reflected in the collection, and vice-versa.
*/
- public Collection values() {
- Values vs = values;
- return (vs != null) ? vs : (values = new Values(this));
+ public ValuesView values() {
+ ValuesView vs = values;
+ return (vs != null) ? vs : (values = new ValuesView(this));
}
/**
@@ -2691,8 +3093,8 @@ public class ConcurrentHashMapV8
* reflect any modifications subsequent to construction.
*/
public Set> entrySet() {
- EntrySet es = entrySet;
- return (es != null) ? es : (entrySet = new EntrySet(this));
+ EntrySetView es = entrySet;
+ return (es != null) ? es : (entrySet = new EntrySetView(this));
}
/**
@@ -2716,27 +3118,27 @@ public class ConcurrentHashMapV8
}
/**
- * Returns a partionable iterator of the keys in this map.
+ * Returns a partitionable iterator of the keys in this map.
*
- * @return a partionable iterator of the keys in this map
+ * @return a partitionable iterator of the keys in this map
*/
public Spliterator keySpliterator() {
return new KeyIterator(this);
}
/**
- * Returns a partionable iterator of the values in this map.
+ * Returns a partitionable iterator of the values in this map.
*
- * @return a partionable iterator of the values in this map
+ * @return a partitionable iterator of the values in this map
*/
public Spliterator valueSpliterator() {
return new ValueIterator(this);
}
/**
- * Returns a partionable iterator of the entries in this map.
+ * Returns a partitionable iterator of the entries in this map.
*
- * @return a partionable iterator of the entries in this map
+ * @return a partitionable iterator of the entries in this map
*/
public Spliterator> entrySpliterator() {
return new EntryIterator(this);
@@ -2751,7 +3153,7 @@ public class ConcurrentHashMapV8
*/
public int hashCode() {
int h = 0;
- InternalIterator it = new InternalIterator(this);
+ Traverser it = new Traverser(this);
Object v;
while ((v = it.advance()) != null) {
h += it.nextKey.hashCode() ^ v.hashCode();
@@ -2771,7 +3173,7 @@ public class ConcurrentHashMapV8
* @return a string representation of this map
*/
public String toString() {
- InternalIterator it = new InternalIterator(this);
+ Traverser it = new Traverser(this);
StringBuilder sb = new StringBuilder();
sb.append('{');
Object v;
@@ -2804,7 +3206,7 @@ public class ConcurrentHashMapV8
if (!(o instanceof Map))
return false;
Map m = (Map) o;
- InternalIterator it = new InternalIterator(this);
+ Traverser it = new Traverser(this);
Object val;
while ((val = it.advance()) != null) {
Object v = m.get(it.nextKey);
@@ -2825,25 +3227,18 @@ public class ConcurrentHashMapV8
/* ----------------Iterators -------------- */
- static final class KeyIterator extends InternalIterator
+ @SuppressWarnings("serial") static final class KeyIterator extends Traverser
implements Spliterator, Enumeration {
KeyIterator(ConcurrentHashMapV8 map) { super(map); }
- KeyIterator(InternalIterator it, boolean split) {
- super(it, split);
+ KeyIterator(ConcurrentHashMapV8 map, Traverser it) {
+ super(map, it, -1);
}
public KeyIterator split() {
- if (last != null || (next != null && nextVal == null))
+ if (nextKey != null)
throw new IllegalStateException();
- return new KeyIterator(this, true);
+ return new KeyIterator(map, this);
}
- public KeyIterator clone() {
- if (last != null || (next != null && nextVal == null))
- throw new IllegalStateException();
- return new KeyIterator(this, false);
- }
-
- @SuppressWarnings("unchecked")
- public final K next() {
+ @SuppressWarnings("unchecked") public final K next() {
if (nextVal == null && advance() == null)
throw new NoSuchElementException();
Object k = nextKey;
@@ -2854,26 +3249,19 @@ public class ConcurrentHashMapV8
public final K nextElement() { return next(); }
}
- static final class ValueIterator extends InternalIterator
+ @SuppressWarnings("serial") static final class ValueIterator extends Traverser
implements Spliterator, Enumeration {
ValueIterator(ConcurrentHashMapV8 map) { super(map); }
- ValueIterator(InternalIterator it, boolean split) {
- super(it, split);
+ ValueIterator(ConcurrentHashMapV8 map, Traverser it) {
+ super(map, it, -1);
}
public ValueIterator split() {
- if (last != null || (next != null && nextVal == null))
+ if (nextKey != null)
throw new IllegalStateException();
- return new ValueIterator(this, true);
+ return new ValueIterator(map, this);
}
- public ValueIterator clone() {
- if (last != null || (next != null && nextVal == null))
- throw new IllegalStateException();
- return new ValueIterator(this, false);
- }
-
- @SuppressWarnings("unchecked")
- public final V next() {
+ @SuppressWarnings("unchecked") public final V next() {
Object v;
if ((v = nextVal) == null && (v = advance()) == null)
throw new NoSuchElementException();
@@ -2884,25 +3272,19 @@ public class ConcurrentHashMapV8
public final V nextElement() { return next(); }
}
- static final class EntryIterator extends InternalIterator
+ @SuppressWarnings("serial") static final class EntryIterator extends Traverser
implements Spliterator> {
EntryIterator(ConcurrentHashMapV8 map) { super(map); }
- EntryIterator(InternalIterator it, boolean split) {
- super(it, split);
+ EntryIterator(ConcurrentHashMapV8 map, Traverser it) {
+ super(map, it, -1);
}
public EntryIterator split() {
- if (last != null || (next != null && nextVal == null))
- throw new IllegalStateException();
- return new EntryIterator(this, true);
- }
- public EntryIterator clone() {
- if (last != null || (next != null && nextVal == null))
+ if (nextKey != null)
throw new IllegalStateException();
- return new EntryIterator(this, false);
+ return new EntryIterator(map, this);
}
- @SuppressWarnings("unchecked")
- public final Map.Entry next() {
+ @SuppressWarnings("unchecked") public final Map.Entry next() {
Object v;
if ((v = nextVal) == null && (v = advance()) == null)
throw new NoSuchElementException();
@@ -2940,8 +3322,8 @@ public class ConcurrentHashMapV8
/**
* Sets our entry's value and writes through to the map. The
- * value to return is somewhat arbitrary here. Since a we do
- * not necessarily track asynchronous changes, the most recent
+ * 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.
@@ -2955,14 +3337,700 @@ public class ConcurrentHashMapV8
}
}
+ /**
+ * Returns exportable snapshot entry for the given key and value
+ * when write-through can't or shouldn't be used.
+ */
+ static AbstractMap.SimpleEntry entryFor(K k, V v) {
+ return new AbstractMap.SimpleEntry(k, v);
+ }
+
+ /* ---------------- Serialization Support -------------- */
+
+ /**
+ * Stripped-down version of helper class used in previous version,
+ * declared for the sake of serialization compatibility
+ */
+ static class Segment 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.
+ */
+ @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();
+ Traverser it = new Traverser(this);
+ Object v;
+ while ((v = it.advance()) != null) {
+ s.writeObject(it.nextKey);
+ s.writeObject(v);
+ }
+ s.writeObject(null);
+ s.writeObject(null);
+ segments = null; // throw away
+ }
+
+ /**
+ * Reconstitutes the instance from a stream (that is, deserializes it).
+ * @param s the stream
+ */
+ @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
+ throws java.io.IOException, ClassNotFoundException {
+ s.defaultReadObject();
+ this.segments = null; // unneeded
+ // initialize transient final field
+ UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
+
+ // 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) {
+ int h = spread(k.hashCode());
+ p = new Node(h, k, v, p);
+ ++size;
+ }
+ else
+ break;
+ }
+ if (p != null) {
+ boolean init = false;
+ int n;
+ if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
+ n = MAXIMUM_CAPACITY;
+ else {
+ int sz = (int)size;
+ n = tableSizeFor(sz + (sz >>> 1) + 1);
+ }
+ int sc = sizeCtl;
+ boolean collide = false;
+ if (n > sc &&
+ UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
+ try {
+ if (table == null) {
+ init = true;
+ Node[] tab = new Node[n];
+ int mask = n - 1;
+ while (p != null) {
+ int j = p.hash & mask;
+ Node next = p.next;
+ Node q = p.next = tabAt(tab, j);
+ setTabAt(tab, j, p);
+ if (!collide && q != null && q.hash == p.hash)
+ collide = true;
+ p = next;
+ }
+ table = tab;
+ counter.add(size);
+ sc = n - (n >>> 2);
+ }
+ } finally {
+ sizeCtl = sc;
+ }
+ if (collide) { // rescan and convert to TreeBins
+ Node[] tab = table;
+ for (int i = 0; i < tab.length; ++i) {
+ int c = 0;
+ for (Node e = tabAt(tab, i); e != null; e = e.next) {
+ if (++c > TREE_THRESHOLD &&
+ (e.key instanceof Comparable)) {
+ replaceWithTreeBin(tab, i, e.key);
+ break;
+ }
+ }
+ }
+ }
+ }
+ if (!init) { // Can only happen if unsafely published.
+ while (p != null) {
+ internalPut(p.key, p.val);
+ p = p.next;
+ }
+ }
+ }
+ }
+
+
+ // -------------------------------------------------------
+
+ // 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 of no arguments */
+ public interface Generator { T apply(); }
+ /** 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 a double to a double */
+ public interface DoubleToDouble { double apply(double a); }
+ /** Interface describing a function mapping a long to a long */
+ public interface LongToLong { long apply(long a); }
+ /** Interface describing a function mapping an int to an int */
+ public interface IntToInt { int apply(int a); }
+ /** 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); }
+
+
+ // -------------------------------------------------------
+
+ /**
+ * Performs the given action for each (key, value).
+ *
+ * @param action the action
+ */
+ public void forEach(BiAction action) {
+ ForkJoinTasks.forEach
+ (this, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each (key, value).
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ * @param action the action
+ */
+ public void forEach(BiFun transformer,
+ Action action) {
+ ForkJoinTasks.forEach
+ (this, 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 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
+ */
+ public U search(BiFun searchFunction) {
+ return ForkJoinTasks.search
+ (this, searchFunction).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 transformer a function returning the transformation
+ * for an element, or null of 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
+ */
+ public U reduce(BiFun transformer,
+ BiFun reducer) {
+ return ForkJoinTasks.reduce
+ (this, 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 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
+ */
+ public double reduceToDouble(ObjectByObjectToDouble transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceToDouble
+ (this, 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 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
+ */
+ public long reduceToLong(ObjectByObjectToLong transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceToLong
+ (this, 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 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
+ */
+ public int reduceToInt(ObjectByObjectToInt transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Performs the given action for each key.
+ *
+ * @param action the action
+ */
+ public void forEachKey(Action action) {
+ ForkJoinTasks.forEachKey
+ (this, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each key.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ * @param action the action
+ */
+ public void forEachKey(Fun transformer,
+ Action action) {
+ ForkJoinTasks.forEachKey
+ (this, 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 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
+ */
+ public U searchKeys(Fun searchFunction) {
+ return ForkJoinTasks.searchKeys
+ (this, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating all keys using the given
+ * reducer to combine values, or null if none.
+ *
+ * @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
+ */
+ public K reduceKeys(BiFun reducer) {
+ return ForkJoinTasks.reduceKeys
+ (this, 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 transformer a function returning the transformation
+ * for an element, or null of 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
+ */
+ public U reduceKeys(Fun transformer,
+ BiFun reducer) {
+ return ForkJoinTasks.reduceKeys
+ (this, 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 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
+ */
+ public double reduceKeysToDouble(ObjectToDouble transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceKeysToDouble
+ (this, 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 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
+ */
+ public long reduceKeysToLong(ObjectToLong transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceKeysToLong
+ (this, 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 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
+ */
+ public int reduceKeysToInt(ObjectToInt transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceKeysToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Performs the given action for each value.
+ *
+ * @param action the action
+ */
+ public void forEachValue(Action action) {
+ ForkJoinTasks.forEachValue
+ (this, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ */
+ public void forEachValue(Fun transformer,
+ Action action) {
+ ForkJoinTasks.forEachValue
+ (this, 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 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
+ *
+ */
+ public U searchValues(Fun searchFunction) {
+ return ForkJoinTasks.searchValues
+ (this, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating all values using the
+ * given reducer to combine values, or null if none.
+ *
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating all values
+ */
+ public V reduceValues(BiFun reducer) {
+ return ForkJoinTasks.reduceValues
+ (this, 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 transformer a function returning the transformation
+ * for an element, or null of 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
+ */
+ public U reduceValues(Fun transformer,
+ BiFun reducer) {
+ return ForkJoinTasks.reduceValues
+ (this, 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 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
+ */
+ public double reduceValuesToDouble(ObjectToDouble transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceValuesToDouble
+ (this, 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 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
+ */
+ public long reduceValuesToLong(ObjectToLong transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceValuesToLong
+ (this, 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 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
+ */
+ public int reduceValuesToInt(ObjectToInt transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceValuesToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Performs the given action for each entry.
+ *
+ * @param action the action
+ */
+ public void forEachEntry(Action> action) {
+ ForkJoinTasks.forEachEntry
+ (this, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each entry.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ * @param action the action
+ */
+ public void forEachEntry(Fun, ? extends U> transformer,
+ Action action) {
+ ForkJoinTasks.forEachEntry
+ (this, 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 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
+ */
+ public U searchEntries(Fun, ? extends U> searchFunction) {
+ return ForkJoinTasks.searchEntries
+ (this, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating all entries using the
+ * given reducer to combine values, or null if none.
+ *
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating all entries
+ */
+ public Map.Entry reduceEntries(BiFun, Map.Entry, ? extends Map.Entry> reducer) {
+ return ForkJoinTasks.reduceEntries
+ (this, 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 transformer a function returning the transformation
+ * for an element, or null of 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
+ */
+ public U reduceEntries(Fun, ? extends U> transformer,
+ BiFun reducer) {
+ return ForkJoinTasks.reduceEntries
+ (this, 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 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
+ */
+ public double reduceEntriesToDouble(ObjectToDouble> transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceEntriesToDouble
+ (this, 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 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
+ */
+ public long reduceEntriesToLong(ObjectToLong> transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceEntriesToLong
+ (this, 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 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
+ */
+ public int reduceEntriesToInt(ObjectToInt> transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceEntriesToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
/* ----------------Views -------------- */
/**
* Base class for views.
*/
- static abstract class MapView {
+ static abstract class CHMView {
final ConcurrentHashMapV8 map;
- MapView(ConcurrentHashMapV8 map) { this.map = map; }
+ CHMView(ConcurrentHashMapV8 map) { this.map = map; }
+
+ /**
+ * Returns the map backing this view.
+ *
+ * @return the map backing this view
+ */
+ public ConcurrentHashMapV8 getMap() { return map; }
+
public final int size() { return map.size(); }
public final boolean isEmpty() { return map.isEmpty(); }
public final void clear() { map.clear(); }
@@ -2975,7 +4043,7 @@ public class ConcurrentHashMapV8
private static final String oomeMsg = "Required array size too large";
public final Object[] toArray() {
- long sz = map.longSize();
+ long sz = map.mappingCount();
if (sz > (long)(MAX_ARRAY_SIZE))
throw new OutOfMemoryError(oomeMsg);
int n = (int)sz;
@@ -2997,9 +4065,8 @@ public class ConcurrentHashMapV8
return (i == n) ? r : Arrays.copyOf(r, i);
}
- @SuppressWarnings("unchecked")
- public final T[] toArray(T[] a) {
- long sz = map.longSize();
+ @SuppressWarnings("unchecked") public final T[] toArray(T[] a) {
+ long sz = map.mappingCount();
if (sz > (long)(MAX_ARRAY_SIZE))
throw new OutOfMemoryError(oomeMsg);
int m = (int)sz;
@@ -3086,18 +4153,66 @@ public class ConcurrentHashMapV8
}
- static final class KeySet