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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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package jsr166e; |
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import jsr166e.LongAdder; |
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1.24 |
import java.util.Arrays; |
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1.1 |
import java.util.Map; |
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import java.util.Set; |
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import java.util.Collection; |
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import java.util.AbstractMap; |
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import java.util.AbstractSet; |
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import java.util.AbstractCollection; |
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import java.util.Hashtable; |
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import java.util.HashMap; |
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import java.util.Iterator; |
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import java.util.Enumeration; |
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import java.util.ConcurrentModificationException; |
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import java.util.NoSuchElementException; |
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import java.util.concurrent.ConcurrentMap; |
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1.24 |
import java.util.concurrent.locks.LockSupport; |
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1.1 |
import java.io.Serializable; |
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/** |
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* A hash table supporting full concurrency of retrievals and |
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* high expected concurrency for updates. This class obeys the |
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* same functional specification as {@link java.util.Hashtable}, and |
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* includes versions of methods corresponding to each method of |
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* {@code Hashtable}. However, even though all operations are |
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* thread-safe, retrieval operations do <em>not</em> entail locking, |
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* and there is <em>not</em> any support for locking the entire table |
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* in a way that prevents all access. This class is fully |
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* interoperable with {@code Hashtable} in programs that rely on its |
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* thread safety but not on its synchronization details. |
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* |
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* <p> Retrieval operations (including {@code get}) generally do not |
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* block, so may overlap with update operations (including {@code put} |
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* and {@code remove}). Retrievals reflect the results of the most |
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* recently <em>completed</em> update operations holding upon their |
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* onset. For aggregate operations such as {@code putAll} and {@code |
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* clear}, concurrent retrievals may reflect insertion or removal of |
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* only some entries. Similarly, Iterators and Enumerations return |
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* elements reflecting the state of the hash table at some point at or |
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* since the creation of the iterator/enumeration. They do |
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* <em>not</em> throw {@link ConcurrentModificationException}. |
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* However, iterators are designed to be used by only one thread at a |
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* time. Bear in mind that the results of aggregate status methods |
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* including {@code size}, {@code isEmpty}, and {@code containsValue} |
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* are typically useful only when a map is not undergoing concurrent |
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* updates in other threads. Otherwise the results of these methods |
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* reflect transient states that may be adequate for monitoring |
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1.16 |
* or estimation purposes, but not for program control. |
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1.1 |
* |
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1.16 |
* <p> The table is dynamically expanded when there are too many |
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* collisions (i.e., keys that have distinct hash codes but fall into |
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* the same slot modulo the table size), with the expected average |
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1.24 |
* effect of maintaining roughly two bins per mapping (corresponding |
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* to a 0.75 load factor threshold for resizing). There may be much |
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* variance around this average as mappings are added and removed, but |
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* overall, this maintains a commonly accepted time/space tradeoff for |
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* hash tables. However, resizing this or any other kind of hash |
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* table may be a relatively slow operation. When possible, it is a |
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* good idea to provide a size estimate as an optional {@code |
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1.16 |
* initialCapacity} constructor argument. An additional optional |
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* {@code loadFactor} constructor argument provides a further means of |
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* customizing initial table capacity by specifying the table density |
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* to be used in calculating the amount of space to allocate for the |
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* given number of elements. Also, for compatibility with previous |
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* versions of this class, constructors may optionally specify an |
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* expected {@code concurrencyLevel} as an additional hint for |
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* internal sizing. Note that using many keys with exactly the same |
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* {@code hashCode{}} is a sure way to slow down performance of any |
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* hash table. |
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1.1 |
* |
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* <p>This class and its views and iterators implement all of the |
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* <em>optional</em> methods of the {@link Map} and {@link Iterator} |
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* interfaces. |
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* |
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* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class |
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* does <em>not</em> allow {@code null} to be used as a key or value. |
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* |
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* <p>This class is a member of the |
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* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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* Java Collections Framework</a>. |
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* |
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* <p><em>jsr166e note: This class is a candidate replacement for |
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* java.util.concurrent.ConcurrentHashMap.<em> |
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* |
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jsr166 |
1.22 |
* @since 1.5 |
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1.1 |
* @author Doug Lea |
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* @param <K> the type of keys maintained by this map |
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* @param <V> the type of mapped values |
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*/ |
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public class ConcurrentHashMapV8<K, V> |
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implements ConcurrentMap<K, V>, Serializable { |
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private static final long serialVersionUID = 7249069246763182397L; |
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/** |
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* A function computing a mapping from the given key to a value, |
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jsr166 |
1.8 |
* or {@code null} if there is no mapping. This is a place-holder |
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* for an upcoming JDK8 interface. |
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1.1 |
*/ |
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public static interface MappingFunction<K, V> { |
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/** |
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* Returns a value for the given key, or null if there is no |
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* mapping. If this function throws an (unchecked) exception, |
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* the exception is rethrown to its caller, and no mapping is |
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* recorded. Because this function is invoked within |
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* atomicity control, the computation should be short and |
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* simple. The most common usage is to construct a new object |
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* serving as an initial mapped value. |
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* |
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* @param key the (non-null) key |
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* @return a value, or null if none |
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*/ |
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V map(K key); |
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} |
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/* |
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* Overview: |
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* |
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* The primary design goal of this hash table is to maintain |
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* concurrent readability (typically method get(), but also |
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* iterators and related methods) while minimizing update |
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1.24 |
* contention. Secondary goals are to keep space consumption about |
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* the same or better than java.util.HashMap, and to support high |
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* initial insertion rates on an empty table by many threads. |
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dl |
1.1 |
* |
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* Each key-value mapping is held in a Node. Because Node fields |
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* can contain special values, they are defined using plain Object |
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* types. Similarly in turn, all internal methods that use them |
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1.14 |
* work off Object types. And similarly, so do the internal |
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* methods of auxiliary iterator and view classes. All public |
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* generic typed methods relay in/out of these internal methods, |
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* supplying null-checks and casts as needed. |
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dl |
1.1 |
* |
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* The table is lazily initialized to a power-of-two size upon the |
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1.14 |
* first insertion. Each bin in the table contains a list of |
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* Nodes (most often, zero or one Node). Table accesses require |
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* volatile/atomic reads, writes, and CASes. Because there is no |
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* other way to arrange this without adding further indirections, |
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* we use intrinsics (sun.misc.Unsafe) operations. The lists of |
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* nodes within bins are always accurately traversable under |
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* volatile reads, so long as lookups check hash code and |
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dl |
1.24 |
* non-nullness of value before checking key equality. |
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* |
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* We use the top two bits of Node hash fields for control |
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* purposes -- they are available anyway because of addressing |
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* constraints. As explained further below, these top bits are |
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* usd as follows: |
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* 00 - Normal |
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* 01 - Locked |
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* 11 - Locked and may have a thread waiting for lock |
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* 10 - Node is a forwarding node |
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* |
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* The lower 30 bits of each Node's hash field contain a |
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* transformation (for better randomization -- method "spread") of |
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* the key's hash code, except for forwarding nodes, for which the |
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* lower bits are zero (and so always have hash field == "MOVED"). |
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dl |
1.14 |
* |
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* Insertion (via put or putIfAbsent) of the first node in an |
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* empty bin is performed by just CASing it to the bin. This is |
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dl |
1.24 |
* by far the most common case for put operations. Other update |
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* operations (insert, delete, and replace) require locks. We do |
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* not want to waste the space required to associate a distinct |
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* lock object with each bin, so instead use the first node of a |
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* bin list itself as a lock. Blocking support for these locks |
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* relies on the builtin "synchronized" monitors. However, we |
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* also need a tryLock construction, so we overlay these by using |
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* bits of the Node hash field for lock control (see above), and |
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* so normally use builtin monitors only for blocking and |
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* signalling using wait/notifyAll constructions. See |
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* Node.tryAwaitLock. |
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* |
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* Using the first node of a list as a lock does not by itself |
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* suffice though: When a node is locked, any update must first |
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* validate that it is still the first node after locking it, and |
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* retry if not. Because new nodes are always appended to lists, |
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* once a node is first in a bin, it remains first until deleted |
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* or the bin becomes invalidated. However, operations that only |
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* conditionally update may inspect nodes until the point of |
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* update. This is a converse of sorts to the lazy locking |
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* technique described by Herlihy & Shavit. |
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dl |
1.14 |
* |
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dl |
1.24 |
* The main disadvantage of per-bin locks is that other update |
188 |
dl |
1.14 |
* operations on other nodes in a bin list protected by the same |
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* lock can stall, for example when user equals() or mapping |
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* functions take a long time. However, statistically, this is |
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* not a common enough problem to outweigh the time/space overhead |
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* of alternatives: Under random hash codes, the frequency of |
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* nodes in bins follows a Poisson distribution |
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* (http://en.wikipedia.org/wiki/Poisson_distribution) with a |
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dl |
1.16 |
* parameter of about 0.5 on average, given the resizing threshold |
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* of 0.75, although with a large variance because of resizing |
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* granularity. Ignoring variance, the expected occurrences of |
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* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The |
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* first few values are: |
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* |
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* 0: 0.607 |
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* 1: 0.303 |
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* 2: 0.076 |
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* 3: 0.012 |
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* more: 0.002 |
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* |
207 |
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* Lock contention probability for two threads accessing distinct |
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* elements is roughly 1 / (8 * #elements). Function "spread" |
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* performs hashCode randomization that improves the likelihood |
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* that these assumptions hold unless users define exactly the |
211 |
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* same value for too many hashCodes. |
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dl |
1.1 |
* |
213 |
dl |
1.24 |
* The table is resized when occupancy exceeds an occupancy |
214 |
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* threshold (nominally, 0.75, but see below). Only a single |
215 |
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* thread performs the resize (using field "sizeCtl", to arrange |
216 |
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* exclusion), but the table otherwise remains usable for reads |
217 |
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* and updates. Resizing proceeds by transferring bins, one by |
218 |
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* one, from the table to the next table. Because we are using |
219 |
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* power-of-two expansion, the elements from each bin must either |
220 |
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* stay at same index, or move with a power of two offset. We |
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* eliminate unnecessary node creation by catching cases where old |
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* nodes can be reused because their next fields won't change. On |
223 |
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* average, only about one-sixth of them need cloning when a table |
224 |
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* doubles. The nodes they replace will be garbage collectable as |
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* soon as they are no longer referenced by any reader thread that |
226 |
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* may be in the midst of concurrently traversing table. Upon |
227 |
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* transfer, the old table bin contains only a special forwarding |
228 |
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* node (with hash field "MOVED") that contains the next table as |
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* its key. On encountering a forwarding node, access and update |
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* operations restart, using the new table. |
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* |
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* Each bin transfer requires its bin lock. However, unlike other |
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* cases, a transfer can skip a bin if it fails to acquire its |
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* lock, and revisit it later. Method rebuild maintains a buffer |
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* of TRANSFER_BUFFER_SIZE bins that have been skipped because of |
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* failure to acquire a lock, and blocks only if none are |
237 |
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* available (i.e., only very rarely). The transfer operation |
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* must also ensure that all accessible bins in both the old and |
239 |
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* new table are usable by any traversal. When there are no lock |
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* acquisition failures, this is arranged simply by proceeding |
241 |
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* from the last bin (table.length - 1) up towards the first. |
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* Upon seeing a forwarding node, traversals (see class |
243 |
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* InternalIterator) arrange to move to the new table without |
244 |
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* revisiting nodes. However, when any node is skipped during a |
245 |
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* transfer, all earlier table bins may have become visible, so |
246 |
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* are initialized with a reverse-forwarding node back to the old |
247 |
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* table until the new ones are established. (This sometimes |
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* requires transiently locking a forwarding node, which is |
249 |
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* possible under the above encoding.) These more expensive |
250 |
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* mechanics trigger only when necessary. |
251 |
dl |
1.14 |
* |
252 |
dl |
1.24 |
* The traversal scheme also applies to partial traversals of |
253 |
dl |
1.14 |
* ranges of bins (via an alternate InternalIterator constructor) |
254 |
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* to support partitioned aggregate operations (that are not |
255 |
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* otherwise implemented yet). Also, read-only operations give up |
256 |
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* if ever forwarded to a null table, which provides support for |
257 |
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* shutdown-style clearing, which is also not currently |
258 |
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* implemented. |
259 |
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* |
260 |
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* Lazy table initialization minimizes footprint until first use, |
261 |
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* and also avoids resizings when the first operation is from a |
262 |
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* putAll, constructor with map argument, or deserialization. |
263 |
dl |
1.24 |
* These cases attempt to override the initial capacity settings, |
264 |
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* but harmlessly fail to take effect in cases of races. |
265 |
dl |
1.1 |
* |
266 |
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* The element count is maintained using a LongAdder, which avoids |
267 |
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* contention on updates but can encounter cache thrashing if read |
268 |
dl |
1.14 |
* too frequently during concurrent access. To avoid reading so |
269 |
dl |
1.2 |
* often, resizing is normally attempted only upon adding to a bin |
270 |
dl |
1.16 |
* already holding two or more nodes. Under uniform hash |
271 |
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* distributions, the probability of this occurring at threshold |
272 |
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* is around 13%, meaning that only about 1 in 8 puts check |
273 |
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* threshold (and after resizing, many fewer do so). But this |
274 |
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* approximation has high variance for small table sizes, so we |
275 |
dl |
1.24 |
* check on any collision for sizes <= 64. |
276 |
dl |
1.14 |
* |
277 |
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* Maintaining API and serialization compatibility with previous |
278 |
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* versions of this class introduces several oddities. Mainly: We |
279 |
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* leave untouched but unused constructor arguments refering to |
280 |
dl |
1.24 |
* concurrencyLevel. We accept a loadFactor constructor argument, |
281 |
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* but apply it only to initial table capacity (which is the only |
282 |
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* time that we can guarantee to honor it.) We also declare an |
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* unused "Segment" class that is instantiated in minimal form |
284 |
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* only when serializing. |
285 |
dl |
1.1 |
*/ |
286 |
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|
287 |
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/* ---------------- Constants -------------- */ |
288 |
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289 |
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/** |
290 |
dl |
1.16 |
* The largest possible table capacity. This value must be |
291 |
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* exactly 1<<30 to stay within Java array allocation and indexing |
292 |
dl |
1.24 |
* bounds for power of two table sizes, and is further required |
293 |
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* because the top two bits of 32bit hash fields are used for |
294 |
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* control purposes. |
295 |
dl |
1.1 |
*/ |
296 |
dl |
1.14 |
private static final int MAXIMUM_CAPACITY = 1 << 30; |
297 |
dl |
1.1 |
|
298 |
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/** |
299 |
dl |
1.14 |
* The default initial table capacity. Must be a power of 2 |
300 |
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* (i.e., at least 1) and at most MAXIMUM_CAPACITY. |
301 |
dl |
1.1 |
*/ |
302 |
dl |
1.14 |
private static final int DEFAULT_CAPACITY = 16; |
303 |
dl |
1.1 |
|
304 |
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/** |
305 |
dl |
1.24 |
* The largest possible (non-power of two) array size. |
306 |
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* Needed by toArray and related methods. |
307 |
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*/ |
308 |
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static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
309 |
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|
310 |
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/** |
311 |
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* The default concurrency level for this table. Unused but |
312 |
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* defined for compatibility with previous versions of this class. |
313 |
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*/ |
314 |
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private static final int DEFAULT_CONCURRENCY_LEVEL = 16; |
315 |
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316 |
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/** |
317 |
dl |
1.16 |
* The load factor for this table. Overrides of this value in |
318 |
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* constructors affect only the initial table capacity. The |
319 |
dl |
1.24 |
* actual floating point value isn't normally used -- it is |
320 |
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* simpler to use expressions such as {@code n - (n >>> 2)} for |
321 |
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* the associated resizing threshold. |
322 |
dl |
1.1 |
*/ |
323 |
dl |
1.16 |
private static final float LOAD_FACTOR = 0.75f; |
324 |
dl |
1.1 |
|
325 |
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/** |
326 |
dl |
1.24 |
* The buffer size for skipped bins during transfers. The |
327 |
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* value is arbitrary but should be large enough to avoid |
328 |
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* most locking stalls during resizes. |
329 |
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*/ |
330 |
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private static final int TRANSFER_BUFFER_SIZE = 32; |
331 |
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|
332 |
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/* |
333 |
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* Encodings for special uses of Node hash fields. See above for |
334 |
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* explanation. |
335 |
dl |
1.1 |
*/ |
336 |
dl |
1.24 |
static final int MOVED = 0x80000000; // hash field for fowarding nodes |
337 |
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static final int LOCKED = 0x40000000; // set/tested only as a bit |
338 |
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static final int WAITING = 0xc0000000; // both bits set/tested together |
339 |
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|
static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash |
340 |
|
|
|
341 |
|
|
/* ---------------- Fields -------------- */ |
342 |
|
|
|
343 |
|
|
/** |
344 |
|
|
* The array of bins. Lazily initialized upon first insertion. |
345 |
|
|
* Size is always a power of two. Accessed directly by iterators. |
346 |
|
|
*/ |
347 |
|
|
transient volatile Node[] table; |
348 |
dl |
1.14 |
|
349 |
dl |
1.16 |
/** |
350 |
dl |
1.24 |
* The counter maintaining number of elements. |
351 |
dl |
1.16 |
*/ |
352 |
dl |
1.24 |
private transient final LongAdder counter; |
353 |
|
|
|
354 |
|
|
/** |
355 |
|
|
* Table initialization and resizing control. When negative, the |
356 |
|
|
* table is being initialized or resized. Otherwise, when table is |
357 |
|
|
* null, holds the initial table size to use upon creation, or 0 |
358 |
|
|
* for default. After initialization, holds the next element count |
359 |
|
|
* value upon which to resize the table. |
360 |
|
|
*/ |
361 |
|
|
private transient volatile int sizeCtl; |
362 |
|
|
|
363 |
|
|
// views |
364 |
|
|
private transient KeySet<K,V> keySet; |
365 |
|
|
private transient Values<K,V> values; |
366 |
|
|
private transient EntrySet<K,V> entrySet; |
367 |
|
|
|
368 |
|
|
/** For serialization compatibility. Null unless serialized; see below */ |
369 |
|
|
private Segment<K,V>[] segments; |
370 |
dl |
1.16 |
|
371 |
dl |
1.14 |
/* ---------------- Nodes -------------- */ |
372 |
dl |
1.1 |
|
373 |
|
|
/** |
374 |
dl |
1.14 |
* Key-value entry. Note that this is never exported out as a |
375 |
dl |
1.24 |
* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry |
376 |
|
|
* below). Nodes with a negative hash field are special, and do |
377 |
|
|
* not contain user keys or values. Otherwise, keys are never |
378 |
|
|
* null, and null val fields indicate that a node is in the |
379 |
|
|
* process of being deleted or created. For purposes of read-only |
380 |
|
|
* access, a key may be read before a val, but can only be used |
381 |
|
|
* after checking val to be non-null. |
382 |
dl |
1.1 |
*/ |
383 |
dl |
1.14 |
static final class Node { |
384 |
dl |
1.24 |
volatile int hash; |
385 |
dl |
1.14 |
final Object key; |
386 |
|
|
volatile Object val; |
387 |
|
|
volatile Node next; |
388 |
|
|
|
389 |
|
|
Node(int hash, Object key, Object val, Node next) { |
390 |
|
|
this.hash = hash; |
391 |
|
|
this.key = key; |
392 |
|
|
this.val = val; |
393 |
|
|
this.next = next; |
394 |
|
|
} |
395 |
|
|
|
396 |
dl |
1.24 |
/** CompareAndSet the hash field */ |
397 |
|
|
final boolean casHash(int cmp, int val) { |
398 |
|
|
return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val); |
399 |
|
|
} |
400 |
dl |
1.1 |
|
401 |
dl |
1.24 |
/** The number of spins before blocking for a lock */ |
402 |
|
|
static final int MAX_SPINS = |
403 |
|
|
Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1; |
404 |
dl |
1.1 |
|
405 |
dl |
1.24 |
/** |
406 |
|
|
* Spins a while if LOCKED bit set and this node is the first |
407 |
|
|
* of its bin, and then sets WAITING bits on hash field and |
408 |
|
|
* blocks (once) if they are still set. It is OK for this |
409 |
|
|
* method to return even if lock is not available upon exit, |
410 |
|
|
* which enables these simple single-wait mechanics. |
411 |
|
|
* |
412 |
|
|
* The corresponding signalling operation is performed within |
413 |
|
|
* callers: Upon detecting that WAITING has been set when |
414 |
|
|
* unlocking lock (via a failed CAS from non-waiting LOCKED |
415 |
|
|
* state), unlockers acquire the sync lock and perform a |
416 |
|
|
* notifyAll. |
417 |
|
|
*/ |
418 |
|
|
final void tryAwaitLock(Node[] tab, int i) { |
419 |
|
|
if (tab != null && i >= 0 && i < tab.length) { // bounds check |
420 |
|
|
int spins = MAX_SPINS, h; |
421 |
|
|
while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) { |
422 |
|
|
if (spins >= 0) { |
423 |
|
|
if (--spins == MAX_SPINS >>> 1) |
424 |
|
|
Thread.yield(); // heuristically yield mid-way |
425 |
|
|
} |
426 |
|
|
else if (casHash(h, h | WAITING)) { |
427 |
jsr166 |
1.26 |
synchronized (this) { |
428 |
dl |
1.24 |
if (tabAt(tab, i) == this && |
429 |
|
|
(hash & WAITING) == WAITING) { |
430 |
|
|
try { |
431 |
|
|
wait(); |
432 |
|
|
} catch (InterruptedException ie) { |
433 |
|
|
Thread.currentThread().interrupt(); |
434 |
|
|
} |
435 |
|
|
} |
436 |
|
|
else |
437 |
|
|
notifyAll(); // possibly won race vs signaller |
438 |
|
|
} |
439 |
|
|
break; |
440 |
|
|
} |
441 |
|
|
} |
442 |
|
|
} |
443 |
|
|
} |
444 |
dl |
1.1 |
|
445 |
dl |
1.24 |
// Unsafe mechanics for casHash |
446 |
|
|
private static final sun.misc.Unsafe UNSAFE; |
447 |
|
|
private static final long hashOffset; |
448 |
dl |
1.1 |
|
449 |
dl |
1.24 |
static { |
450 |
|
|
try { |
451 |
|
|
UNSAFE = getUnsafe(); |
452 |
|
|
Class<?> k = Node.class; |
453 |
|
|
hashOffset = UNSAFE.objectFieldOffset |
454 |
|
|
(k.getDeclaredField("hash")); |
455 |
|
|
} catch (Exception e) { |
456 |
|
|
throw new Error(e); |
457 |
|
|
} |
458 |
|
|
} |
459 |
|
|
} |
460 |
dl |
1.1 |
|
461 |
dl |
1.14 |
/* ---------------- Table element access -------------- */ |
462 |
dl |
1.1 |
|
463 |
|
|
/* |
464 |
jsr166 |
1.7 |
* Volatile access methods are used for table elements as well as |
465 |
dl |
1.14 |
* elements of in-progress next table while resizing. Uses are |
466 |
|
|
* null checked by callers, and implicitly bounds-checked, relying |
467 |
|
|
* on the invariants that tab arrays have non-zero size, and all |
468 |
|
|
* indices are masked with (tab.length - 1) which is never |
469 |
|
|
* negative and always less than length. Note that, to be correct |
470 |
|
|
* wrt arbitrary concurrency errors by users, bounds checks must |
471 |
|
|
* operate on local variables, which accounts for some odd-looking |
472 |
|
|
* inline assignments below. |
473 |
dl |
1.1 |
*/ |
474 |
|
|
|
475 |
dl |
1.14 |
static final Node tabAt(Node[] tab, int i) { // used by InternalIterator |
476 |
dl |
1.1 |
return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE); |
477 |
|
|
} |
478 |
|
|
|
479 |
|
|
private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) { |
480 |
|
|
return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v); |
481 |
|
|
} |
482 |
|
|
|
483 |
|
|
private static final void setTabAt(Node[] tab, int i, Node v) { |
484 |
|
|
UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v); |
485 |
|
|
} |
486 |
|
|
|
487 |
dl |
1.14 |
/* ---------------- Internal access and update methods -------------- */ |
488 |
|
|
|
489 |
|
|
/** |
490 |
|
|
* Applies a supplemental hash function to a given hashCode, which |
491 |
|
|
* defends against poor quality hash functions. The result must |
492 |
dl |
1.24 |
* be have the top 2 bits clear. For reasonable performance, this |
493 |
|
|
* function must have good avalanche properties; i.e., that each |
494 |
|
|
* bit of the argument affects each bit of the result. (Although |
495 |
|
|
* we don't care about the unused top 2 bits.) |
496 |
dl |
1.14 |
*/ |
497 |
|
|
private static final int spread(int h) { |
498 |
|
|
// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/ |
499 |
|
|
h ^= h >>> 16; |
500 |
|
|
h *= 0x85ebca6b; |
501 |
|
|
h ^= h >>> 13; |
502 |
|
|
h *= 0xc2b2ae35; |
503 |
dl |
1.24 |
return ((h >>> 16) ^ h) & HASH_BITS; // mask out top bits |
504 |
dl |
1.14 |
} |
505 |
dl |
1.1 |
|
506 |
dl |
1.14 |
/** Implementation for get and containsKey */ |
507 |
jsr166 |
1.4 |
private final Object internalGet(Object k) { |
508 |
dl |
1.1 |
int h = spread(k.hashCode()); |
509 |
dl |
1.14 |
retry: for (Node[] tab = table; tab != null;) { |
510 |
dl |
1.24 |
Node e; Object ek, ev; int eh; // locals to read fields once |
511 |
dl |
1.14 |
for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) { |
512 |
dl |
1.24 |
if ((eh = e.hash) == MOVED) { |
513 |
|
|
tab = (Node[])e.key; // restart with new table |
514 |
dl |
1.1 |
continue retry; |
515 |
|
|
} |
516 |
dl |
1.24 |
if ((eh & HASH_BITS) == h && (ev = e.val) != null && |
517 |
|
|
((ek = e.key) == k || k.equals(ek))) |
518 |
|
|
return ev; |
519 |
dl |
1.1 |
} |
520 |
|
|
break; |
521 |
|
|
} |
522 |
|
|
return null; |
523 |
|
|
} |
524 |
|
|
|
525 |
dl |
1.10 |
/** Implementation for put and putIfAbsent */ |
526 |
dl |
1.1 |
private final Object internalPut(Object k, Object v, boolean replace) { |
527 |
|
|
int h = spread(k.hashCode()); |
528 |
dl |
1.14 |
Object oldVal = null; // previous value or null if none |
529 |
|
|
for (Node[] tab = table;;) { |
530 |
dl |
1.24 |
int i; Node f; int fh; Object fk, fv; |
531 |
dl |
1.1 |
if (tab == null) |
532 |
dl |
1.24 |
tab = initTable(); |
533 |
|
|
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
534 |
dl |
1.2 |
if (casTabAt(tab, i, null, new Node(h, k, v, null))) |
535 |
dl |
1.14 |
break; // no lock when adding to empty bin |
536 |
|
|
} |
537 |
dl |
1.24 |
else if ((fh = f.hash) == MOVED) |
538 |
|
|
tab = (Node[])f.key; |
539 |
|
|
else if (!replace && (fh & HASH_BITS) == h && (fv = f.val) != null && |
540 |
|
|
((fk = f.key) == k || k.equals(fk))) { |
541 |
|
|
oldVal = fv; // precheck 1st node for putIfAbsent |
542 |
|
|
break; |
543 |
dl |
1.1 |
} |
544 |
dl |
1.24 |
else if ((fh & LOCKED) != 0) |
545 |
|
|
f.tryAwaitLock(tab, i); |
546 |
|
|
else if (f.casHash(fh, fh | LOCKED)) { |
547 |
dl |
1.1 |
boolean validated = false; |
548 |
|
|
boolean checkSize = false; |
549 |
dl |
1.24 |
try { |
550 |
|
|
if (tabAt(tab, i) == f) { |
551 |
dl |
1.14 |
validated = true; // retry if 1st already deleted |
552 |
dl |
1.24 |
for (Node e = f;;) { |
553 |
|
|
Object ek, ev; |
554 |
|
|
if ((e.hash & HASH_BITS) == h && |
555 |
|
|
(ev = e.val) != null && |
556 |
|
|
((ek = e.key) == k || k.equals(ek))) { |
557 |
dl |
1.1 |
oldVal = ev; |
558 |
|
|
if (replace) |
559 |
|
|
e.val = v; |
560 |
dl |
1.10 |
break; |
561 |
dl |
1.1 |
} |
562 |
dl |
1.10 |
Node last = e; |
563 |
|
|
if ((e = e.next) == null) { |
564 |
dl |
1.2 |
last.next = new Node(h, k, v, null); |
565 |
dl |
1.24 |
if (last != f || tab.length <= 64) |
566 |
dl |
1.1 |
checkSize = true; |
567 |
dl |
1.10 |
break; |
568 |
dl |
1.1 |
} |
569 |
|
|
} |
570 |
|
|
} |
571 |
dl |
1.24 |
} finally { // unlock and signal if needed |
572 |
|
|
if (!f.casHash(fh | LOCKED, fh)) { |
573 |
|
|
f.hash = fh; |
574 |
jsr166 |
1.26 |
synchronized (f) { f.notifyAll(); }; |
575 |
dl |
1.24 |
} |
576 |
dl |
1.1 |
} |
577 |
|
|
if (validated) { |
578 |
dl |
1.24 |
int sc; |
579 |
dl |
1.1 |
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
580 |
dl |
1.24 |
(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc) |
581 |
dl |
1.14 |
growTable(); |
582 |
dl |
1.1 |
break; |
583 |
|
|
} |
584 |
|
|
} |
585 |
|
|
} |
586 |
|
|
if (oldVal == null) |
587 |
dl |
1.14 |
counter.increment(); // update counter outside of locks |
588 |
dl |
1.1 |
return oldVal; |
589 |
|
|
} |
590 |
|
|
|
591 |
|
|
/** |
592 |
dl |
1.10 |
* Implementation for the four public remove/replace methods: |
593 |
|
|
* Replaces node value with v, conditional upon match of cv if |
594 |
|
|
* non-null. If resulting value is null, delete. |
595 |
dl |
1.1 |
*/ |
596 |
|
|
private final Object internalReplace(Object k, Object v, Object cv) { |
597 |
|
|
int h = spread(k.hashCode()); |
598 |
dl |
1.24 |
Object oldVal = null; |
599 |
dl |
1.14 |
for (Node[] tab = table;;) { |
600 |
dl |
1.24 |
Node f; int i, fh; |
601 |
dl |
1.14 |
if (tab == null || |
602 |
dl |
1.24 |
(f = tabAt(tab, i = (tab.length - 1) & h)) == null) |
603 |
|
|
break; |
604 |
|
|
else if ((fh = f.hash) == MOVED) |
605 |
|
|
tab = (Node[])f.key; |
606 |
|
|
else if ((fh & HASH_BITS) != h && f.next == null) // precheck |
607 |
|
|
break; // rules out possible existence |
608 |
|
|
else if ((fh & LOCKED) != 0) |
609 |
|
|
f.tryAwaitLock(tab, i); |
610 |
|
|
else if (f.casHash(fh, fh | LOCKED)) { |
611 |
dl |
1.1 |
boolean validated = false; |
612 |
|
|
boolean deleted = false; |
613 |
dl |
1.24 |
try { |
614 |
|
|
if (tabAt(tab, i) == f) { |
615 |
dl |
1.10 |
validated = true; |
616 |
dl |
1.24 |
for (Node e = f, pred = null;;) { |
617 |
dl |
1.10 |
Object ek, ev; |
618 |
dl |
1.24 |
if ((e.hash & HASH_BITS) == h && |
619 |
|
|
((ev = e.val) != null) && |
620 |
|
|
((ek = e.key) == k || k.equals(ek))) { |
621 |
dl |
1.1 |
if (cv == null || cv == ev || cv.equals(ev)) { |
622 |
|
|
oldVal = ev; |
623 |
|
|
if ((e.val = v) == null) { |
624 |
|
|
deleted = true; |
625 |
|
|
Node en = e.next; |
626 |
|
|
if (pred != null) |
627 |
|
|
pred.next = en; |
628 |
|
|
else |
629 |
|
|
setTabAt(tab, i, en); |
630 |
|
|
} |
631 |
|
|
} |
632 |
dl |
1.10 |
break; |
633 |
dl |
1.1 |
} |
634 |
dl |
1.24 |
pred = e; |
635 |
|
|
if ((e = e.next) == null) |
636 |
|
|
break; |
637 |
|
|
} |
638 |
|
|
} |
639 |
|
|
} finally { |
640 |
|
|
if (!f.casHash(fh | LOCKED, fh)) { |
641 |
|
|
f.hash = fh; |
642 |
jsr166 |
1.26 |
synchronized (f) { f.notifyAll(); }; |
643 |
dl |
1.1 |
} |
644 |
|
|
} |
645 |
|
|
if (validated) { |
646 |
|
|
if (deleted) |
647 |
|
|
counter.decrement(); |
648 |
dl |
1.24 |
break; |
649 |
dl |
1.1 |
} |
650 |
|
|
} |
651 |
|
|
} |
652 |
dl |
1.24 |
return oldVal; |
653 |
dl |
1.1 |
} |
654 |
|
|
|
655 |
dl |
1.14 |
/** Implementation for computeIfAbsent and compute. Like put, but messier. */ |
656 |
dl |
1.24 |
// Todo: Somehow reinstate non-termination check |
657 |
dl |
1.1 |
@SuppressWarnings("unchecked") |
658 |
dl |
1.2 |
private final V internalCompute(K k, |
659 |
dl |
1.24 |
MappingFunction<? super K, ? extends V> fn, |
660 |
dl |
1.2 |
boolean replace) { |
661 |
dl |
1.1 |
int h = spread(k.hashCode()); |
662 |
|
|
V val = null; |
663 |
|
|
boolean added = false; |
664 |
|
|
Node[] tab = table; |
665 |
dl |
1.14 |
outer:for (;;) { |
666 |
dl |
1.24 |
Node f; int i, fh; Object fk, fv; |
667 |
dl |
1.1 |
if (tab == null) |
668 |
dl |
1.24 |
tab = initTable(); |
669 |
|
|
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
670 |
|
|
Node node = new Node(fh = h | LOCKED, k, null, null); |
671 |
dl |
1.10 |
boolean validated = false; |
672 |
dl |
1.24 |
if (casTabAt(tab, i, null, node)) { |
673 |
|
|
validated = true; |
674 |
|
|
try { |
675 |
|
|
val = fn.map(k); |
676 |
|
|
if (val != null) { |
677 |
|
|
node.val = val; |
678 |
|
|
added = true; |
679 |
|
|
} |
680 |
|
|
} finally { |
681 |
|
|
if (!added) |
682 |
|
|
setTabAt(tab, i, null); |
683 |
|
|
if (!node.casHash(fh, h)) { |
684 |
dl |
1.25 |
node.hash = h; |
685 |
jsr166 |
1.26 |
synchronized (node) { node.notifyAll(); }; |
686 |
dl |
1.1 |
} |
687 |
|
|
} |
688 |
|
|
} |
689 |
dl |
1.10 |
if (validated) |
690 |
|
|
break; |
691 |
dl |
1.1 |
} |
692 |
dl |
1.24 |
else if ((fh = f.hash) == MOVED) |
693 |
|
|
tab = (Node[])f.key; |
694 |
|
|
else if (!replace && (fh & HASH_BITS) == h && (fv = f.val) != null && |
695 |
|
|
((fk = f.key) == k || k.equals(fk))) { |
696 |
|
|
if (tabAt(tab, i) == f) { |
697 |
|
|
val = (V)fv; |
698 |
dl |
1.14 |
break; |
699 |
|
|
} |
700 |
|
|
} |
701 |
dl |
1.24 |
else if ((fh & LOCKED) != 0) |
702 |
|
|
f.tryAwaitLock(tab, i); |
703 |
|
|
else if (f.casHash(fh, fh | LOCKED)) { |
704 |
dl |
1.10 |
boolean validated = false; |
705 |
dl |
1.1 |
boolean checkSize = false; |
706 |
dl |
1.24 |
try { |
707 |
|
|
if (tabAt(tab, i) == f) { |
708 |
dl |
1.10 |
validated = true; |
709 |
dl |
1.24 |
for (Node e = f;;) { |
710 |
|
|
Object ek, ev, v; |
711 |
|
|
if ((e.hash & HASH_BITS) == h && |
712 |
|
|
(ev = e.val) != null && |
713 |
|
|
((ek = e.key) == k || k.equals(ek))) { |
714 |
|
|
if (replace && (v = fn.map(k)) != null) |
715 |
|
|
ev = e.val = v; |
716 |
dl |
1.1 |
val = (V)ev; |
717 |
dl |
1.10 |
break; |
718 |
dl |
1.1 |
} |
719 |
dl |
1.10 |
Node last = e; |
720 |
|
|
if ((e = e.next) == null) { |
721 |
dl |
1.24 |
if ((val = fn.map(k)) != null) { |
722 |
dl |
1.2 |
last.next = new Node(h, k, val, null); |
723 |
|
|
added = true; |
724 |
dl |
1.24 |
if (last != f || tab.length <= 64) |
725 |
dl |
1.1 |
checkSize = true; |
726 |
|
|
} |
727 |
dl |
1.10 |
break; |
728 |
dl |
1.1 |
} |
729 |
|
|
} |
730 |
|
|
} |
731 |
dl |
1.24 |
} finally { |
732 |
|
|
if (!f.casHash(fh | LOCKED, fh)) { |
733 |
|
|
f.hash = fh; |
734 |
jsr166 |
1.26 |
synchronized (f) { f.notifyAll(); }; |
735 |
dl |
1.24 |
} |
736 |
dl |
1.1 |
} |
737 |
dl |
1.10 |
if (validated) { |
738 |
dl |
1.24 |
int sc; |
739 |
dl |
1.10 |
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
740 |
dl |
1.24 |
(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc) |
741 |
dl |
1.14 |
growTable(); |
742 |
dl |
1.10 |
break; |
743 |
|
|
} |
744 |
dl |
1.1 |
} |
745 |
dl |
1.10 |
} |
746 |
dl |
1.1 |
if (added) |
747 |
|
|
counter.increment(); |
748 |
|
|
return val; |
749 |
|
|
} |
750 |
|
|
|
751 |
|
|
/** |
752 |
dl |
1.2 |
* Implementation for clear. Steps through each bin, removing all nodes. |
753 |
dl |
1.1 |
*/ |
754 |
|
|
private final void internalClear() { |
755 |
dl |
1.14 |
long delta = 0L; // negative number of deletions |
756 |
dl |
1.1 |
int i = 0; |
757 |
|
|
Node[] tab = table; |
758 |
|
|
while (tab != null && i < tab.length) { |
759 |
dl |
1.24 |
int fh; |
760 |
|
|
Node f = tabAt(tab, i); |
761 |
|
|
if (f == null) |
762 |
dl |
1.1 |
++i; |
763 |
dl |
1.24 |
else if ((fh = f.hash) == MOVED) |
764 |
|
|
tab = (Node[])f.key; |
765 |
|
|
else if ((fh & LOCKED) != 0) |
766 |
|
|
f.tryAwaitLock(tab, i); |
767 |
|
|
else if (f.casHash(fh, fh | LOCKED)) { |
768 |
dl |
1.1 |
boolean validated = false; |
769 |
dl |
1.24 |
try { |
770 |
|
|
if (tabAt(tab, i) == f) { |
771 |
dl |
1.1 |
validated = true; |
772 |
dl |
1.24 |
for (Node e = f; e != null; e = e.next) { |
773 |
dl |
1.14 |
if (e.val != null) { // currently always true |
774 |
dl |
1.1 |
e.val = null; |
775 |
dl |
1.14 |
--delta; |
776 |
dl |
1.1 |
} |
777 |
dl |
1.24 |
} |
778 |
dl |
1.1 |
setTabAt(tab, i, null); |
779 |
|
|
} |
780 |
dl |
1.24 |
} finally { |
781 |
|
|
if (!f.casHash(fh | LOCKED, fh)) { |
782 |
|
|
f.hash = fh; |
783 |
jsr166 |
1.26 |
synchronized (f) { f.notifyAll(); }; |
784 |
dl |
1.24 |
} |
785 |
dl |
1.1 |
} |
786 |
dl |
1.14 |
if (validated) |
787 |
dl |
1.1 |
++i; |
788 |
|
|
} |
789 |
|
|
} |
790 |
dl |
1.14 |
counter.add(delta); |
791 |
dl |
1.1 |
} |
792 |
|
|
|
793 |
dl |
1.24 |
/* ----------------Table Initialization and Resizing -------------- */ |
794 |
|
|
|
795 |
|
|
/** |
796 |
|
|
* Returns a power of two table size for the given desired capacity. |
797 |
|
|
* See Hackers Delight, sec 3.2 |
798 |
|
|
*/ |
799 |
|
|
private static final int tableSizeFor(int c) { |
800 |
|
|
int n = c - 1; |
801 |
|
|
n |= n >>> 1; |
802 |
|
|
n |= n >>> 2; |
803 |
|
|
n |= n >>> 4; |
804 |
|
|
n |= n >>> 8; |
805 |
|
|
n |= n >>> 16; |
806 |
|
|
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; |
807 |
|
|
} |
808 |
|
|
|
809 |
|
|
/** |
810 |
|
|
* Initializes table, using the size recorded in sizeCtl. |
811 |
|
|
*/ |
812 |
|
|
private final Node[] initTable() { |
813 |
|
|
Node[] tab; int sc; |
814 |
|
|
while ((tab = table) == null) { |
815 |
|
|
if ((sc = sizeCtl) < 0) |
816 |
|
|
Thread.yield(); // lost initialization race; just spin |
817 |
|
|
else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
818 |
|
|
try { |
819 |
|
|
if ((tab = table) == null) { |
820 |
|
|
int n = (sc > 0) ? sc : DEFAULT_CAPACITY; |
821 |
|
|
tab = table = new Node[n]; |
822 |
|
|
sc = n - (n >>> 2) - 1; |
823 |
|
|
} |
824 |
|
|
} finally { |
825 |
|
|
sizeCtl = sc; |
826 |
|
|
} |
827 |
|
|
break; |
828 |
|
|
} |
829 |
|
|
} |
830 |
|
|
return tab; |
831 |
|
|
} |
832 |
|
|
|
833 |
|
|
/** |
834 |
|
|
* If not already resizing, creates next table and transfers bins. |
835 |
|
|
* Rechecks occupancy after a transfer to see if another resize is |
836 |
|
|
* already needed because resizings are lagging additions. |
837 |
|
|
*/ |
838 |
|
|
private final void growTable() { |
839 |
|
|
int sc = sizeCtl; |
840 |
|
|
if (sc >= 0 && UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
841 |
|
|
try { |
842 |
|
|
Node[] tab; int n; |
843 |
|
|
while ((tab = table) != null && |
844 |
|
|
(n = tab.length) > 0 && n < MAXIMUM_CAPACITY && |
845 |
|
|
counter.sum() >= (long)sc) { |
846 |
|
|
table = rebuild(tab); |
847 |
|
|
sc = (n << 1) - (n >>> 1) - 1; |
848 |
|
|
} |
849 |
|
|
} finally { |
850 |
|
|
sizeCtl = sc; |
851 |
|
|
} |
852 |
|
|
} |
853 |
|
|
} |
854 |
|
|
|
855 |
|
|
/* |
856 |
|
|
* Moves and/or copies the nodes in each bin to new table. See |
857 |
|
|
* above for explanation. |
858 |
|
|
* |
859 |
|
|
* @return the new table |
860 |
|
|
*/ |
861 |
|
|
private static final Node[] rebuild(Node[] tab) { |
862 |
|
|
int n = tab.length; |
863 |
|
|
Node[] nextTab = new Node[n << 1]; |
864 |
|
|
Node fwd = new Node(MOVED, nextTab, null, null); |
865 |
|
|
int[] buffer = null; // holds bins to revisit; null until needed |
866 |
|
|
Node rev = null; // reverse forwarder; null until needed |
867 |
|
|
int nbuffered = 0; // the number of bins in buffer list |
868 |
|
|
int bufferIndex = 0; // buffer index of current buffered bin |
869 |
|
|
int bin = n - 1; // current non-buffered bin or -1 if none |
870 |
|
|
|
871 |
|
|
for (int i = bin;;) { // start upwards sweep |
872 |
|
|
int fh; Node f; |
873 |
|
|
if ((f = tabAt(tab, i)) == null) { |
874 |
|
|
if (bin >= 0) { // no lock needed (or available) |
875 |
|
|
if (!casTabAt(tab, i, f, fwd)) |
876 |
|
|
continue; |
877 |
|
|
} |
878 |
|
|
else { // transiently use a locked forwarding node |
879 |
|
|
Node g = new Node(MOVED|LOCKED, nextTab, null, null); |
880 |
|
|
if (!casTabAt(tab, i, f, g)) |
881 |
|
|
continue; |
882 |
|
|
setTabAt(nextTab, i, null); |
883 |
|
|
setTabAt(nextTab, i + n, null); |
884 |
|
|
setTabAt(tab, i, fwd); |
885 |
|
|
if (!g.casHash(MOVED|LOCKED, MOVED)) { |
886 |
|
|
g.hash = MOVED; |
887 |
jsr166 |
1.26 |
synchronized (g) { g.notifyAll(); } |
888 |
dl |
1.24 |
} |
889 |
|
|
} |
890 |
|
|
} |
891 |
|
|
else if (((fh = f.hash) & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) { |
892 |
|
|
boolean validated = false; |
893 |
|
|
try { // split to lo and hi lists; copying as needed |
894 |
|
|
if (tabAt(tab, i) == f) { |
895 |
|
|
validated = true; |
896 |
|
|
Node e = f, lastRun = f; |
897 |
|
|
Node lo = null, hi = null; |
898 |
|
|
int runBit = e.hash & n; |
899 |
|
|
for (Node p = e.next; p != null; p = p.next) { |
900 |
|
|
int b = p.hash & n; |
901 |
|
|
if (b != runBit) { |
902 |
|
|
runBit = b; |
903 |
|
|
lastRun = p; |
904 |
|
|
} |
905 |
|
|
} |
906 |
|
|
if (runBit == 0) |
907 |
|
|
lo = lastRun; |
908 |
|
|
else |
909 |
|
|
hi = lastRun; |
910 |
|
|
for (Node p = e; p != lastRun; p = p.next) { |
911 |
|
|
int ph = p.hash & HASH_BITS; |
912 |
|
|
Object pk = p.key, pv = p.val; |
913 |
|
|
if ((ph & n) == 0) |
914 |
|
|
lo = new Node(ph, pk, pv, lo); |
915 |
|
|
else |
916 |
|
|
hi = new Node(ph, pk, pv, hi); |
917 |
|
|
} |
918 |
|
|
setTabAt(nextTab, i, lo); |
919 |
|
|
setTabAt(nextTab, i + n, hi); |
920 |
|
|
setTabAt(tab, i, fwd); |
921 |
|
|
} |
922 |
|
|
} finally { |
923 |
|
|
if (!f.casHash(fh | LOCKED, fh)) { |
924 |
|
|
f.hash = fh; |
925 |
jsr166 |
1.26 |
synchronized (f) { f.notifyAll(); }; |
926 |
dl |
1.24 |
} |
927 |
|
|
} |
928 |
|
|
if (!validated) |
929 |
|
|
continue; |
930 |
|
|
} |
931 |
|
|
else { |
932 |
|
|
if (buffer == null) // initialize buffer for revisits |
933 |
|
|
buffer = new int[TRANSFER_BUFFER_SIZE]; |
934 |
|
|
if (bin < 0 && bufferIndex > 0) { |
935 |
|
|
int j = buffer[--bufferIndex]; |
936 |
|
|
buffer[bufferIndex] = i; |
937 |
|
|
i = j; // swap with another bin |
938 |
|
|
continue; |
939 |
|
|
} |
940 |
|
|
if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) { |
941 |
|
|
f.tryAwaitLock(tab, i); |
942 |
|
|
continue; // no other options -- block |
943 |
|
|
} |
944 |
|
|
if (rev == null) // initialize reverse-forwarder |
945 |
|
|
rev = new Node(MOVED, tab, null, null); |
946 |
|
|
if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0) |
947 |
|
|
continue; // recheck before adding to list |
948 |
|
|
buffer[nbuffered++] = i; |
949 |
|
|
setTabAt(nextTab, i, rev); // install place-holders |
950 |
|
|
setTabAt(nextTab, i + n, rev); |
951 |
|
|
} |
952 |
|
|
|
953 |
|
|
if (bin > 0) |
954 |
|
|
i = --bin; |
955 |
|
|
else if (buffer != null && nbuffered > 0) { |
956 |
|
|
bin = -1; |
957 |
|
|
i = buffer[bufferIndex = --nbuffered]; |
958 |
|
|
} |
959 |
|
|
else |
960 |
|
|
return nextTab; |
961 |
|
|
} |
962 |
|
|
} |
963 |
|
|
|
964 |
dl |
1.14 |
/* ----------------Table Traversal -------------- */ |
965 |
|
|
|
966 |
dl |
1.1 |
/** |
967 |
dl |
1.14 |
* Encapsulates traversal for methods such as containsValue; also |
968 |
|
|
* serves as a base class for other iterators. |
969 |
|
|
* |
970 |
|
|
* At each step, the iterator snapshots the key ("nextKey") and |
971 |
|
|
* value ("nextVal") of a valid node (i.e., one that, at point of |
972 |
|
|
* snapshot, has a nonnull user value). Because val fields can |
973 |
|
|
* change (including to null, indicating deletion), field nextVal |
974 |
|
|
* might not be accurate at point of use, but still maintains the |
975 |
|
|
* weak consistency property of holding a value that was once |
976 |
|
|
* valid. |
977 |
|
|
* |
978 |
|
|
* Internal traversals directly access these fields, as in: |
979 |
jsr166 |
1.23 |
* {@code while (it.next != null) { process(it.nextKey); it.advance(); }} |
980 |
dl |
1.14 |
* |
981 |
|
|
* Exported iterators (subclasses of ViewIterator) extract key, |
982 |
|
|
* value, or key-value pairs as return values of Iterator.next(), |
983 |
jsr166 |
1.17 |
* and encapsulate the it.next check as hasNext(); |
984 |
dl |
1.14 |
* |
985 |
|
|
* The iterator visits each valid node that was reachable upon |
986 |
|
|
* iterator construction once. It might miss some that were added |
987 |
|
|
* to a bin after the bin was visited, which is OK wrt consistency |
988 |
|
|
* guarantees. Maintaining this property in the face of possible |
989 |
|
|
* ongoing resizes requires a fair amount of bookkeeping state |
990 |
|
|
* that is difficult to optimize away amidst volatile accesses. |
991 |
|
|
* Even so, traversal maintains reasonable throughput. |
992 |
|
|
* |
993 |
|
|
* Normally, iteration proceeds bin-by-bin traversing lists. |
994 |
|
|
* However, if the table has been resized, then all future steps |
995 |
|
|
* must traverse both the bin at the current index as well as at |
996 |
|
|
* (index + baseSize); and so on for further resizings. To |
997 |
|
|
* paranoically cope with potential sharing by users of iterators |
998 |
|
|
* across threads, iteration terminates if a bounds checks fails |
999 |
|
|
* for a table read. |
1000 |
|
|
* |
1001 |
|
|
* The range-based constructor enables creation of parallel |
1002 |
|
|
* range-splitting traversals. (Not yet implemented.) |
1003 |
|
|
*/ |
1004 |
|
|
static class InternalIterator { |
1005 |
|
|
Node next; // the next entry to use |
1006 |
|
|
Node last; // the last entry used |
1007 |
|
|
Object nextKey; // cached key field of next |
1008 |
|
|
Object nextVal; // cached val field of next |
1009 |
|
|
Node[] tab; // current table; updated if resized |
1010 |
|
|
int index; // index of bin to use next |
1011 |
|
|
int baseIndex; // current index of initial table |
1012 |
|
|
final int baseLimit; // index bound for initial table |
1013 |
|
|
final int baseSize; // initial table size |
1014 |
|
|
|
1015 |
|
|
/** Creates iterator for all entries in the table. */ |
1016 |
|
|
InternalIterator(Node[] tab) { |
1017 |
|
|
this.tab = tab; |
1018 |
|
|
baseLimit = baseSize = (tab == null) ? 0 : tab.length; |
1019 |
|
|
index = baseIndex = 0; |
1020 |
|
|
next = null; |
1021 |
|
|
advance(); |
1022 |
|
|
} |
1023 |
|
|
|
1024 |
|
|
/** Creates iterator for the given range of the table */ |
1025 |
|
|
InternalIterator(Node[] tab, int lo, int hi) { |
1026 |
|
|
this.tab = tab; |
1027 |
|
|
baseSize = (tab == null) ? 0 : tab.length; |
1028 |
jsr166 |
1.15 |
baseLimit = (hi <= baseSize) ? hi : baseSize; |
1029 |
dl |
1.14 |
index = baseIndex = lo; |
1030 |
|
|
next = null; |
1031 |
|
|
advance(); |
1032 |
|
|
} |
1033 |
|
|
|
1034 |
|
|
/** Advances next. See above for explanation. */ |
1035 |
|
|
final void advance() { |
1036 |
|
|
Node e = last = next; |
1037 |
|
|
outer: do { |
1038 |
dl |
1.24 |
if (e != null) // advance past used/skipped node |
1039 |
dl |
1.1 |
e = e.next; |
1040 |
dl |
1.24 |
while (e == null) { // get to next non-null bin |
1041 |
|
|
Node[] t; int b, i, n; // checks must use locals |
1042 |
dl |
1.14 |
if ((b = baseIndex) >= baseLimit || (i = index) < 0 || |
1043 |
|
|
(t = tab) == null || i >= (n = t.length)) |
1044 |
|
|
break outer; |
1045 |
dl |
1.24 |
else if ((e = tabAt(t, i)) != null && e.hash == MOVED) |
1046 |
|
|
tab = (Node[])e.key; // restarts due to null val |
1047 |
|
|
else // visit upper slots if present |
1048 |
dl |
1.14 |
index = (i += baseSize) < n ? i : (baseIndex = b + 1); |
1049 |
dl |
1.1 |
} |
1050 |
dl |
1.14 |
nextKey = e.key; |
1051 |
dl |
1.24 |
} while ((nextVal = e.val) == null);// skip deleted or special nodes |
1052 |
dl |
1.14 |
next = e; |
1053 |
dl |
1.1 |
} |
1054 |
|
|
} |
1055 |
|
|
|
1056 |
|
|
/* ---------------- Public operations -------------- */ |
1057 |
|
|
|
1058 |
|
|
/** |
1059 |
dl |
1.16 |
* Creates a new, empty map with the default initial table size (16), |
1060 |
dl |
1.1 |
*/ |
1061 |
dl |
1.16 |
public ConcurrentHashMapV8() { |
1062 |
dl |
1.14 |
this.counter = new LongAdder(); |
1063 |
dl |
1.1 |
} |
1064 |
|
|
|
1065 |
|
|
/** |
1066 |
dl |
1.16 |
* Creates a new, empty map with an initial table size |
1067 |
|
|
* accommodating the specified number of elements without the need |
1068 |
|
|
* to dynamically resize. |
1069 |
dl |
1.1 |
* |
1070 |
|
|
* @param initialCapacity The implementation performs internal |
1071 |
|
|
* sizing to accommodate this many elements. |
1072 |
|
|
* @throws IllegalArgumentException if the initial capacity of |
1073 |
jsr166 |
1.18 |
* elements is negative |
1074 |
dl |
1.1 |
*/ |
1075 |
dl |
1.16 |
public ConcurrentHashMapV8(int initialCapacity) { |
1076 |
|
|
if (initialCapacity < 0) |
1077 |
|
|
throw new IllegalArgumentException(); |
1078 |
|
|
int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? |
1079 |
|
|
MAXIMUM_CAPACITY : |
1080 |
|
|
tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); |
1081 |
|
|
this.counter = new LongAdder(); |
1082 |
dl |
1.24 |
this.sizeCtl = cap; |
1083 |
dl |
1.1 |
} |
1084 |
|
|
|
1085 |
|
|
/** |
1086 |
dl |
1.16 |
* Creates a new map with the same mappings as the given map. |
1087 |
dl |
1.1 |
* |
1088 |
dl |
1.16 |
* @param m the map |
1089 |
dl |
1.1 |
*/ |
1090 |
dl |
1.16 |
public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) { |
1091 |
|
|
this.counter = new LongAdder(); |
1092 |
dl |
1.24 |
this.sizeCtl = DEFAULT_CAPACITY; |
1093 |
dl |
1.16 |
putAll(m); |
1094 |
dl |
1.1 |
} |
1095 |
|
|
|
1096 |
|
|
/** |
1097 |
dl |
1.16 |
* Creates a new, empty map with an initial table size based on |
1098 |
|
|
* the given number of elements ({@code initialCapacity}) and |
1099 |
|
|
* initial table density ({@code loadFactor}). |
1100 |
|
|
* |
1101 |
|
|
* @param initialCapacity the initial capacity. The implementation |
1102 |
|
|
* performs internal sizing to accommodate this many elements, |
1103 |
|
|
* given the specified load factor. |
1104 |
|
|
* @param loadFactor the load factor (table density) for |
1105 |
jsr166 |
1.18 |
* establishing the initial table size |
1106 |
dl |
1.16 |
* @throws IllegalArgumentException if the initial capacity of |
1107 |
|
|
* elements is negative or the load factor is nonpositive |
1108 |
jsr166 |
1.22 |
* |
1109 |
|
|
* @since 1.6 |
1110 |
dl |
1.1 |
*/ |
1111 |
dl |
1.16 |
public ConcurrentHashMapV8(int initialCapacity, float loadFactor) { |
1112 |
|
|
this(initialCapacity, loadFactor, 1); |
1113 |
dl |
1.1 |
} |
1114 |
|
|
|
1115 |
|
|
/** |
1116 |
dl |
1.16 |
* Creates a new, empty map with an initial table size based on |
1117 |
|
|
* the given number of elements ({@code initialCapacity}), table |
1118 |
|
|
* density ({@code loadFactor}), and number of concurrently |
1119 |
|
|
* updating threads ({@code concurrencyLevel}). |
1120 |
dl |
1.1 |
* |
1121 |
dl |
1.16 |
* @param initialCapacity the initial capacity. The implementation |
1122 |
|
|
* performs internal sizing to accommodate this many elements, |
1123 |
|
|
* given the specified load factor. |
1124 |
|
|
* @param loadFactor the load factor (table density) for |
1125 |
jsr166 |
1.18 |
* establishing the initial table size |
1126 |
dl |
1.16 |
* @param concurrencyLevel the estimated number of concurrently |
1127 |
|
|
* updating threads. The implementation may use this value as |
1128 |
|
|
* a sizing hint. |
1129 |
|
|
* @throws IllegalArgumentException if the initial capacity is |
1130 |
|
|
* negative or the load factor or concurrencyLevel are |
1131 |
jsr166 |
1.18 |
* nonpositive |
1132 |
dl |
1.1 |
*/ |
1133 |
dl |
1.16 |
public ConcurrentHashMapV8(int initialCapacity, |
1134 |
|
|
float loadFactor, int concurrencyLevel) { |
1135 |
|
|
if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) |
1136 |
|
|
throw new IllegalArgumentException(); |
1137 |
|
|
if (initialCapacity < concurrencyLevel) // Use at least as many bins |
1138 |
|
|
initialCapacity = concurrencyLevel; // as estimated threads |
1139 |
|
|
long size = (long)(1.0 + (long)initialCapacity / loadFactor); |
1140 |
|
|
int cap = ((size >= (long)MAXIMUM_CAPACITY) ? |
1141 |
|
|
MAXIMUM_CAPACITY: tableSizeFor((int)size)); |
1142 |
|
|
this.counter = new LongAdder(); |
1143 |
dl |
1.24 |
this.sizeCtl = cap; |
1144 |
dl |
1.1 |
} |
1145 |
|
|
|
1146 |
|
|
/** |
1147 |
dl |
1.14 |
* {@inheritDoc} |
1148 |
dl |
1.1 |
*/ |
1149 |
|
|
public boolean isEmpty() { |
1150 |
dl |
1.2 |
return counter.sum() <= 0L; // ignore transient negative values |
1151 |
dl |
1.1 |
} |
1152 |
|
|
|
1153 |
|
|
/** |
1154 |
dl |
1.14 |
* {@inheritDoc} |
1155 |
dl |
1.1 |
*/ |
1156 |
|
|
public int size() { |
1157 |
|
|
long n = counter.sum(); |
1158 |
jsr166 |
1.15 |
return ((n < 0L) ? 0 : |
1159 |
|
|
(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : |
1160 |
dl |
1.14 |
(int)n); |
1161 |
dl |
1.1 |
} |
1162 |
|
|
|
1163 |
dl |
1.24 |
final long longSize() { // accurate version of size needed for views |
1164 |
|
|
long n = counter.sum(); |
1165 |
|
|
return (n < 0L) ? 0L : n; |
1166 |
|
|
} |
1167 |
|
|
|
1168 |
dl |
1.1 |
/** |
1169 |
|
|
* Returns the value to which the specified key is mapped, |
1170 |
|
|
* or {@code null} if this map contains no mapping for the key. |
1171 |
|
|
* |
1172 |
|
|
* <p>More formally, if this map contains a mapping from a key |
1173 |
|
|
* {@code k} to a value {@code v} such that {@code key.equals(k)}, |
1174 |
|
|
* then this method returns {@code v}; otherwise it returns |
1175 |
|
|
* {@code null}. (There can be at most one such mapping.) |
1176 |
|
|
* |
1177 |
|
|
* @throws NullPointerException if the specified key is null |
1178 |
|
|
*/ |
1179 |
|
|
@SuppressWarnings("unchecked") |
1180 |
|
|
public V get(Object key) { |
1181 |
|
|
if (key == null) |
1182 |
|
|
throw new NullPointerException(); |
1183 |
|
|
return (V)internalGet(key); |
1184 |
|
|
} |
1185 |
|
|
|
1186 |
|
|
/** |
1187 |
|
|
* Tests if the specified object is a key in this table. |
1188 |
|
|
* |
1189 |
|
|
* @param key possible key |
1190 |
|
|
* @return {@code true} if and only if the specified object |
1191 |
|
|
* is a key in this table, as determined by the |
1192 |
jsr166 |
1.18 |
* {@code equals} method; {@code false} otherwise |
1193 |
dl |
1.1 |
* @throws NullPointerException if the specified key is null |
1194 |
|
|
*/ |
1195 |
|
|
public boolean containsKey(Object key) { |
1196 |
|
|
if (key == null) |
1197 |
|
|
throw new NullPointerException(); |
1198 |
|
|
return internalGet(key) != null; |
1199 |
|
|
} |
1200 |
|
|
|
1201 |
|
|
/** |
1202 |
|
|
* Returns {@code true} if this map maps one or more keys to the |
1203 |
dl |
1.14 |
* specified value. Note: This method may require a full traversal |
1204 |
|
|
* of the map, and is much slower than method {@code containsKey}. |
1205 |
dl |
1.1 |
* |
1206 |
|
|
* @param value value whose presence in this map is to be tested |
1207 |
|
|
* @return {@code true} if this map maps one or more keys to the |
1208 |
|
|
* specified value |
1209 |
|
|
* @throws NullPointerException if the specified value is null |
1210 |
|
|
*/ |
1211 |
|
|
public boolean containsValue(Object value) { |
1212 |
|
|
if (value == null) |
1213 |
|
|
throw new NullPointerException(); |
1214 |
dl |
1.14 |
Object v; |
1215 |
|
|
InternalIterator it = new InternalIterator(table); |
1216 |
|
|
while (it.next != null) { |
1217 |
|
|
if ((v = it.nextVal) == value || value.equals(v)) |
1218 |
|
|
return true; |
1219 |
|
|
it.advance(); |
1220 |
|
|
} |
1221 |
|
|
return false; |
1222 |
dl |
1.1 |
} |
1223 |
|
|
|
1224 |
|
|
/** |
1225 |
|
|
* Legacy method testing if some key maps into the specified value |
1226 |
|
|
* in this table. This method is identical in functionality to |
1227 |
|
|
* {@link #containsValue}, and exists solely to ensure |
1228 |
|
|
* full compatibility with class {@link java.util.Hashtable}, |
1229 |
|
|
* which supported this method prior to introduction of the |
1230 |
|
|
* Java Collections framework. |
1231 |
|
|
* |
1232 |
|
|
* @param value a value to search for |
1233 |
|
|
* @return {@code true} if and only if some key maps to the |
1234 |
|
|
* {@code value} argument in this table as |
1235 |
|
|
* determined by the {@code equals} method; |
1236 |
|
|
* {@code false} otherwise |
1237 |
|
|
* @throws NullPointerException if the specified value is null |
1238 |
|
|
*/ |
1239 |
|
|
public boolean contains(Object value) { |
1240 |
|
|
return containsValue(value); |
1241 |
|
|
} |
1242 |
|
|
|
1243 |
|
|
/** |
1244 |
|
|
* Maps the specified key to the specified value in this table. |
1245 |
|
|
* Neither the key nor the value can be null. |
1246 |
|
|
* |
1247 |
|
|
* <p> The value can be retrieved by calling the {@code get} method |
1248 |
|
|
* with a key that is equal to the original key. |
1249 |
|
|
* |
1250 |
|
|
* @param key key with which the specified value is to be associated |
1251 |
|
|
* @param value value to be associated with the specified key |
1252 |
|
|
* @return the previous value associated with {@code key}, or |
1253 |
|
|
* {@code null} if there was no mapping for {@code key} |
1254 |
|
|
* @throws NullPointerException if the specified key or value is null |
1255 |
|
|
*/ |
1256 |
|
|
@SuppressWarnings("unchecked") |
1257 |
|
|
public V put(K key, V value) { |
1258 |
|
|
if (key == null || value == null) |
1259 |
|
|
throw new NullPointerException(); |
1260 |
|
|
return (V)internalPut(key, value, true); |
1261 |
|
|
} |
1262 |
|
|
|
1263 |
|
|
/** |
1264 |
|
|
* {@inheritDoc} |
1265 |
|
|
* |
1266 |
|
|
* @return the previous value associated with the specified key, |
1267 |
|
|
* or {@code null} if there was no mapping for the key |
1268 |
|
|
* @throws NullPointerException if the specified key or value is null |
1269 |
|
|
*/ |
1270 |
|
|
@SuppressWarnings("unchecked") |
1271 |
|
|
public V putIfAbsent(K key, V value) { |
1272 |
|
|
if (key == null || value == null) |
1273 |
|
|
throw new NullPointerException(); |
1274 |
|
|
return (V)internalPut(key, value, false); |
1275 |
|
|
} |
1276 |
|
|
|
1277 |
|
|
/** |
1278 |
|
|
* Copies all of the mappings from the specified map to this one. |
1279 |
|
|
* These mappings replace any mappings that this map had for any of the |
1280 |
|
|
* keys currently in the specified map. |
1281 |
|
|
* |
1282 |
|
|
* @param m mappings to be stored in this map |
1283 |
|
|
*/ |
1284 |
|
|
public void putAll(Map<? extends K, ? extends V> m) { |
1285 |
|
|
if (m == null) |
1286 |
|
|
throw new NullPointerException(); |
1287 |
dl |
1.14 |
/* |
1288 |
dl |
1.24 |
* If uninitialized, try to preallocate big enough table |
1289 |
dl |
1.14 |
*/ |
1290 |
|
|
if (table == null) { |
1291 |
|
|
int size = m.size(); |
1292 |
dl |
1.24 |
int n = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : |
1293 |
dl |
1.16 |
tableSizeFor(size + (size >>> 1) + 1); |
1294 |
dl |
1.24 |
int sc = sizeCtl; |
1295 |
|
|
if (n < sc) |
1296 |
|
|
n = sc; |
1297 |
|
|
if (sc >= 0 && |
1298 |
|
|
UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
1299 |
|
|
try { |
1300 |
|
|
if (table == null) { |
1301 |
|
|
table = new Node[n]; |
1302 |
|
|
sc = n - (n >>> 2) - 1; |
1303 |
|
|
} |
1304 |
|
|
} finally { |
1305 |
|
|
sizeCtl = sc; |
1306 |
|
|
} |
1307 |
|
|
} |
1308 |
|
|
} |
1309 |
|
|
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) { |
1310 |
|
|
Object ek = e.getKey(), ev = e.getValue(); |
1311 |
|
|
if (ek == null || ev == null) |
1312 |
|
|
throw new NullPointerException(); |
1313 |
|
|
internalPut(ek, ev, true); |
1314 |
dl |
1.14 |
} |
1315 |
dl |
1.1 |
} |
1316 |
|
|
|
1317 |
|
|
/** |
1318 |
|
|
* If the specified key is not already associated with a value, |
1319 |
|
|
* computes its value using the given mappingFunction, and if |
1320 |
|
|
* non-null, enters it into the map. This is equivalent to |
1321 |
jsr166 |
1.13 |
* <pre> {@code |
1322 |
|
|
* if (map.containsKey(key)) |
1323 |
|
|
* return map.get(key); |
1324 |
|
|
* value = mappingFunction.map(key); |
1325 |
|
|
* if (value != null) |
1326 |
|
|
* map.put(key, value); |
1327 |
|
|
* return value;}</pre> |
1328 |
dl |
1.1 |
* |
1329 |
|
|
* except that the action is performed atomically. Some attempted |
1330 |
dl |
1.5 |
* update operations on this map by other threads may be blocked |
1331 |
|
|
* while computation is in progress, so the computation should be |
1332 |
|
|
* short and simple, and must not attempt to update any other |
1333 |
|
|
* mappings of this Map. The most appropriate usage is to |
1334 |
|
|
* construct a new object serving as an initial mapped value, or |
1335 |
|
|
* memoized result, as in: |
1336 |
jsr166 |
1.13 |
* <pre> {@code |
1337 |
dl |
1.5 |
* map.computeIfAbsent(key, new MappingFunction<K, V>() { |
1338 |
jsr166 |
1.13 |
* public V map(K k) { return new Value(f(k)); }});}</pre> |
1339 |
dl |
1.1 |
* |
1340 |
|
|
* @param key key with which the specified value is to be associated |
1341 |
|
|
* @param mappingFunction the function to compute a value |
1342 |
|
|
* @return the current (existing or computed) value associated with |
1343 |
|
|
* the specified key, or {@code null} if the computation |
1344 |
jsr166 |
1.18 |
* returned {@code null} |
1345 |
dl |
1.1 |
* @throws NullPointerException if the specified key or mappingFunction |
1346 |
jsr166 |
1.18 |
* is null |
1347 |
dl |
1.5 |
* @throws IllegalStateException if the computation detectably |
1348 |
|
|
* attempts a recursive update to this map that would |
1349 |
jsr166 |
1.18 |
* otherwise never complete |
1350 |
dl |
1.1 |
* @throws RuntimeException or Error if the mappingFunction does so, |
1351 |
jsr166 |
1.18 |
* in which case the mapping is left unestablished |
1352 |
dl |
1.1 |
*/ |
1353 |
|
|
public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) { |
1354 |
|
|
if (key == null || mappingFunction == null) |
1355 |
|
|
throw new NullPointerException(); |
1356 |
dl |
1.2 |
return internalCompute(key, mappingFunction, false); |
1357 |
|
|
} |
1358 |
|
|
|
1359 |
|
|
/** |
1360 |
dl |
1.5 |
* Computes the value associated with the given key using the given |
1361 |
dl |
1.2 |
* mappingFunction, and if non-null, enters it into the map. This |
1362 |
|
|
* is equivalent to |
1363 |
jsr166 |
1.13 |
* <pre> {@code |
1364 |
|
|
* value = mappingFunction.map(key); |
1365 |
|
|
* if (value != null) |
1366 |
|
|
* map.put(key, value); |
1367 |
|
|
* else |
1368 |
|
|
* value = map.get(key); |
1369 |
|
|
* return value;}</pre> |
1370 |
dl |
1.2 |
* |
1371 |
|
|
* except that the action is performed atomically. Some attempted |
1372 |
dl |
1.5 |
* update operations on this map by other threads may be blocked |
1373 |
|
|
* while computation is in progress, so the computation should be |
1374 |
|
|
* short and simple, and must not attempt to update any other |
1375 |
|
|
* mappings of this Map. |
1376 |
dl |
1.2 |
* |
1377 |
|
|
* @param key key with which the specified value is to be associated |
1378 |
|
|
* @param mappingFunction the function to compute a value |
1379 |
|
|
* @return the current value associated with |
1380 |
|
|
* the specified key, or {@code null} if the computation |
1381 |
jsr166 |
1.18 |
* returned {@code null} and the value was not otherwise present |
1382 |
dl |
1.2 |
* @throws NullPointerException if the specified key or mappingFunction |
1383 |
jsr166 |
1.18 |
* is null |
1384 |
dl |
1.5 |
* @throws IllegalStateException if the computation detectably |
1385 |
|
|
* attempts a recursive update to this map that would |
1386 |
jsr166 |
1.18 |
* otherwise never complete |
1387 |
dl |
1.2 |
* @throws RuntimeException or Error if the mappingFunction does so, |
1388 |
jsr166 |
1.18 |
* in which case the mapping is unchanged |
1389 |
dl |
1.2 |
*/ |
1390 |
|
|
public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) { |
1391 |
|
|
if (key == null || mappingFunction == null) |
1392 |
|
|
throw new NullPointerException(); |
1393 |
|
|
return internalCompute(key, mappingFunction, true); |
1394 |
dl |
1.1 |
} |
1395 |
|
|
|
1396 |
|
|
/** |
1397 |
|
|
* Removes the key (and its corresponding value) from this map. |
1398 |
|
|
* This method does nothing if the key is not in the map. |
1399 |
|
|
* |
1400 |
|
|
* @param key the key that needs to be removed |
1401 |
|
|
* @return the previous value associated with {@code key}, or |
1402 |
|
|
* {@code null} if there was no mapping for {@code key} |
1403 |
|
|
* @throws NullPointerException if the specified key is null |
1404 |
|
|
*/ |
1405 |
|
|
@SuppressWarnings("unchecked") |
1406 |
|
|
public V remove(Object key) { |
1407 |
|
|
if (key == null) |
1408 |
|
|
throw new NullPointerException(); |
1409 |
jsr166 |
1.3 |
return (V)internalReplace(key, null, null); |
1410 |
dl |
1.1 |
} |
1411 |
|
|
|
1412 |
|
|
/** |
1413 |
|
|
* {@inheritDoc} |
1414 |
|
|
* |
1415 |
|
|
* @throws NullPointerException if the specified key is null |
1416 |
|
|
*/ |
1417 |
|
|
public boolean remove(Object key, Object value) { |
1418 |
|
|
if (key == null) |
1419 |
|
|
throw new NullPointerException(); |
1420 |
|
|
if (value == null) |
1421 |
|
|
return false; |
1422 |
|
|
return internalReplace(key, null, value) != null; |
1423 |
|
|
} |
1424 |
|
|
|
1425 |
|
|
/** |
1426 |
|
|
* {@inheritDoc} |
1427 |
|
|
* |
1428 |
|
|
* @throws NullPointerException if any of the arguments are null |
1429 |
|
|
*/ |
1430 |
|
|
public boolean replace(K key, V oldValue, V newValue) { |
1431 |
|
|
if (key == null || oldValue == null || newValue == null) |
1432 |
|
|
throw new NullPointerException(); |
1433 |
jsr166 |
1.3 |
return internalReplace(key, newValue, oldValue) != null; |
1434 |
dl |
1.1 |
} |
1435 |
|
|
|
1436 |
|
|
/** |
1437 |
|
|
* {@inheritDoc} |
1438 |
|
|
* |
1439 |
|
|
* @return the previous value associated with the specified key, |
1440 |
|
|
* or {@code null} if there was no mapping for the key |
1441 |
|
|
* @throws NullPointerException if the specified key or value is null |
1442 |
|
|
*/ |
1443 |
|
|
@SuppressWarnings("unchecked") |
1444 |
|
|
public V replace(K key, V value) { |
1445 |
|
|
if (key == null || value == null) |
1446 |
|
|
throw new NullPointerException(); |
1447 |
jsr166 |
1.3 |
return (V)internalReplace(key, value, null); |
1448 |
dl |
1.1 |
} |
1449 |
|
|
|
1450 |
|
|
/** |
1451 |
|
|
* Removes all of the mappings from this map. |
1452 |
|
|
*/ |
1453 |
|
|
public void clear() { |
1454 |
|
|
internalClear(); |
1455 |
|
|
} |
1456 |
|
|
|
1457 |
|
|
/** |
1458 |
|
|
* Returns a {@link Set} view of the keys contained in this map. |
1459 |
|
|
* The set is backed by the map, so changes to the map are |
1460 |
|
|
* reflected in the set, and vice-versa. The set supports element |
1461 |
|
|
* removal, which removes the corresponding mapping from this map, |
1462 |
|
|
* via the {@code Iterator.remove}, {@code Set.remove}, |
1463 |
|
|
* {@code removeAll}, {@code retainAll}, and {@code clear} |
1464 |
|
|
* operations. It does not support the {@code add} or |
1465 |
|
|
* {@code addAll} operations. |
1466 |
|
|
* |
1467 |
|
|
* <p>The view's {@code iterator} is a "weakly consistent" iterator |
1468 |
|
|
* that will never throw {@link ConcurrentModificationException}, |
1469 |
|
|
* and guarantees to traverse elements as they existed upon |
1470 |
|
|
* construction of the iterator, and may (but is not guaranteed to) |
1471 |
|
|
* reflect any modifications subsequent to construction. |
1472 |
|
|
*/ |
1473 |
|
|
public Set<K> keySet() { |
1474 |
dl |
1.14 |
KeySet<K,V> ks = keySet; |
1475 |
|
|
return (ks != null) ? ks : (keySet = new KeySet<K,V>(this)); |
1476 |
dl |
1.1 |
} |
1477 |
|
|
|
1478 |
|
|
/** |
1479 |
|
|
* Returns a {@link Collection} view of the values contained in this map. |
1480 |
|
|
* The collection is backed by the map, so changes to the map are |
1481 |
|
|
* reflected in the collection, and vice-versa. The collection |
1482 |
|
|
* supports element removal, which removes the corresponding |
1483 |
|
|
* mapping from this map, via the {@code Iterator.remove}, |
1484 |
|
|
* {@code Collection.remove}, {@code removeAll}, |
1485 |
|
|
* {@code retainAll}, and {@code clear} operations. It does not |
1486 |
|
|
* support the {@code add} or {@code addAll} operations. |
1487 |
|
|
* |
1488 |
|
|
* <p>The view's {@code iterator} is a "weakly consistent" iterator |
1489 |
|
|
* that will never throw {@link ConcurrentModificationException}, |
1490 |
|
|
* and guarantees to traverse elements as they existed upon |
1491 |
|
|
* construction of the iterator, and may (but is not guaranteed to) |
1492 |
|
|
* reflect any modifications subsequent to construction. |
1493 |
|
|
*/ |
1494 |
|
|
public Collection<V> values() { |
1495 |
dl |
1.14 |
Values<K,V> vs = values; |
1496 |
|
|
return (vs != null) ? vs : (values = new Values<K,V>(this)); |
1497 |
dl |
1.1 |
} |
1498 |
|
|
|
1499 |
|
|
/** |
1500 |
|
|
* Returns a {@link Set} view of the mappings contained in this map. |
1501 |
|
|
* The set is backed by the map, so changes to the map are |
1502 |
|
|
* reflected in the set, and vice-versa. The set supports element |
1503 |
|
|
* removal, which removes the corresponding mapping from the map, |
1504 |
|
|
* via the {@code Iterator.remove}, {@code Set.remove}, |
1505 |
|
|
* {@code removeAll}, {@code retainAll}, and {@code clear} |
1506 |
|
|
* operations. It does not support the {@code add} or |
1507 |
|
|
* {@code addAll} operations. |
1508 |
|
|
* |
1509 |
|
|
* <p>The view's {@code iterator} is a "weakly consistent" iterator |
1510 |
|
|
* that will never throw {@link ConcurrentModificationException}, |
1511 |
|
|
* and guarantees to traverse elements as they existed upon |
1512 |
|
|
* construction of the iterator, and may (but is not guaranteed to) |
1513 |
|
|
* reflect any modifications subsequent to construction. |
1514 |
|
|
*/ |
1515 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
1516 |
dl |
1.14 |
EntrySet<K,V> es = entrySet; |
1517 |
|
|
return (es != null) ? es : (entrySet = new EntrySet<K,V>(this)); |
1518 |
dl |
1.1 |
} |
1519 |
|
|
|
1520 |
|
|
/** |
1521 |
|
|
* Returns an enumeration of the keys in this table. |
1522 |
|
|
* |
1523 |
|
|
* @return an enumeration of the keys in this table |
1524 |
|
|
* @see #keySet() |
1525 |
|
|
*/ |
1526 |
|
|
public Enumeration<K> keys() { |
1527 |
dl |
1.14 |
return new KeyIterator<K,V>(this); |
1528 |
dl |
1.1 |
} |
1529 |
|
|
|
1530 |
|
|
/** |
1531 |
|
|
* Returns an enumeration of the values in this table. |
1532 |
|
|
* |
1533 |
|
|
* @return an enumeration of the values in this table |
1534 |
|
|
* @see #values() |
1535 |
|
|
*/ |
1536 |
|
|
public Enumeration<V> elements() { |
1537 |
dl |
1.14 |
return new ValueIterator<K,V>(this); |
1538 |
dl |
1.1 |
} |
1539 |
|
|
|
1540 |
|
|
/** |
1541 |
dl |
1.2 |
* Returns the hash code value for this {@link Map}, i.e., |
1542 |
|
|
* the sum of, for each key-value pair in the map, |
1543 |
|
|
* {@code key.hashCode() ^ value.hashCode()}. |
1544 |
|
|
* |
1545 |
|
|
* @return the hash code value for this map |
1546 |
dl |
1.1 |
*/ |
1547 |
|
|
public int hashCode() { |
1548 |
dl |
1.14 |
int h = 0; |
1549 |
|
|
InternalIterator it = new InternalIterator(table); |
1550 |
|
|
while (it.next != null) { |
1551 |
|
|
h += it.nextKey.hashCode() ^ it.nextVal.hashCode(); |
1552 |
|
|
it.advance(); |
1553 |
|
|
} |
1554 |
|
|
return h; |
1555 |
dl |
1.1 |
} |
1556 |
|
|
|
1557 |
|
|
/** |
1558 |
dl |
1.2 |
* Returns a string representation of this map. The string |
1559 |
|
|
* representation consists of a list of key-value mappings (in no |
1560 |
|
|
* particular order) enclosed in braces ("{@code {}}"). Adjacent |
1561 |
|
|
* mappings are separated by the characters {@code ", "} (comma |
1562 |
|
|
* and space). Each key-value mapping is rendered as the key |
1563 |
|
|
* followed by an equals sign ("{@code =}") followed by the |
1564 |
|
|
* associated value. |
1565 |
|
|
* |
1566 |
|
|
* @return a string representation of this map |
1567 |
dl |
1.1 |
*/ |
1568 |
|
|
public String toString() { |
1569 |
dl |
1.14 |
InternalIterator it = new InternalIterator(table); |
1570 |
|
|
StringBuilder sb = new StringBuilder(); |
1571 |
|
|
sb.append('{'); |
1572 |
|
|
if (it.next != null) { |
1573 |
|
|
for (;;) { |
1574 |
|
|
Object k = it.nextKey, v = it.nextVal; |
1575 |
|
|
sb.append(k == this ? "(this Map)" : k); |
1576 |
|
|
sb.append('='); |
1577 |
|
|
sb.append(v == this ? "(this Map)" : v); |
1578 |
|
|
it.advance(); |
1579 |
|
|
if (it.next == null) |
1580 |
|
|
break; |
1581 |
|
|
sb.append(',').append(' '); |
1582 |
|
|
} |
1583 |
|
|
} |
1584 |
|
|
return sb.append('}').toString(); |
1585 |
dl |
1.1 |
} |
1586 |
|
|
|
1587 |
|
|
/** |
1588 |
dl |
1.2 |
* Compares the specified object with this map for equality. |
1589 |
|
|
* Returns {@code true} if the given object is a map with the same |
1590 |
|
|
* mappings as this map. This operation may return misleading |
1591 |
|
|
* results if either map is concurrently modified during execution |
1592 |
|
|
* of this method. |
1593 |
|
|
* |
1594 |
|
|
* @param o object to be compared for equality with this map |
1595 |
|
|
* @return {@code true} if the specified object is equal to this map |
1596 |
dl |
1.1 |
*/ |
1597 |
|
|
public boolean equals(Object o) { |
1598 |
dl |
1.14 |
if (o != this) { |
1599 |
|
|
if (!(o instanceof Map)) |
1600 |
|
|
return false; |
1601 |
|
|
Map<?,?> m = (Map<?,?>) o; |
1602 |
|
|
InternalIterator it = new InternalIterator(table); |
1603 |
|
|
while (it.next != null) { |
1604 |
|
|
Object val = it.nextVal; |
1605 |
|
|
Object v = m.get(it.nextKey); |
1606 |
|
|
if (v == null || (v != val && !v.equals(val))) |
1607 |
dl |
1.1 |
return false; |
1608 |
dl |
1.14 |
it.advance(); |
1609 |
|
|
} |
1610 |
dl |
1.1 |
for (Map.Entry<?,?> e : m.entrySet()) { |
1611 |
dl |
1.14 |
Object mk, mv, v; |
1612 |
|
|
if ((mk = e.getKey()) == null || |
1613 |
|
|
(mv = e.getValue()) == null || |
1614 |
|
|
(v = internalGet(mk)) == null || |
1615 |
|
|
(mv != v && !mv.equals(v))) |
1616 |
dl |
1.1 |
return false; |
1617 |
|
|
} |
1618 |
dl |
1.14 |
} |
1619 |
|
|
return true; |
1620 |
|
|
} |
1621 |
|
|
|
1622 |
|
|
/* ----------------Iterators -------------- */ |
1623 |
|
|
|
1624 |
|
|
/** |
1625 |
|
|
* Base class for key, value, and entry iterators. Adds a map |
1626 |
|
|
* reference to InternalIterator to support Iterator.remove. |
1627 |
|
|
*/ |
1628 |
|
|
static abstract class ViewIterator<K,V> extends InternalIterator { |
1629 |
|
|
final ConcurrentHashMapV8<K, V> map; |
1630 |
|
|
ViewIterator(ConcurrentHashMapV8<K, V> map) { |
1631 |
|
|
super(map.table); |
1632 |
|
|
this.map = map; |
1633 |
|
|
} |
1634 |
|
|
|
1635 |
|
|
public final void remove() { |
1636 |
|
|
if (last == null) |
1637 |
|
|
throw new IllegalStateException(); |
1638 |
|
|
map.remove(last.key); |
1639 |
|
|
last = null; |
1640 |
|
|
} |
1641 |
|
|
|
1642 |
|
|
public final boolean hasNext() { return next != null; } |
1643 |
|
|
public final boolean hasMoreElements() { return next != null; } |
1644 |
|
|
} |
1645 |
|
|
|
1646 |
|
|
static final class KeyIterator<K,V> extends ViewIterator<K,V> |
1647 |
|
|
implements Iterator<K>, Enumeration<K> { |
1648 |
|
|
KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1649 |
|
|
|
1650 |
|
|
@SuppressWarnings("unchecked") |
1651 |
|
|
public final K next() { |
1652 |
|
|
if (next == null) |
1653 |
|
|
throw new NoSuchElementException(); |
1654 |
|
|
Object k = nextKey; |
1655 |
|
|
advance(); |
1656 |
|
|
return (K)k; |
1657 |
|
|
} |
1658 |
|
|
|
1659 |
|
|
public final K nextElement() { return next(); } |
1660 |
|
|
} |
1661 |
|
|
|
1662 |
|
|
static final class ValueIterator<K,V> extends ViewIterator<K,V> |
1663 |
|
|
implements Iterator<V>, Enumeration<V> { |
1664 |
|
|
ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1665 |
|
|
|
1666 |
|
|
@SuppressWarnings("unchecked") |
1667 |
|
|
public final V next() { |
1668 |
|
|
if (next == null) |
1669 |
|
|
throw new NoSuchElementException(); |
1670 |
|
|
Object v = nextVal; |
1671 |
|
|
advance(); |
1672 |
|
|
return (V)v; |
1673 |
|
|
} |
1674 |
|
|
|
1675 |
|
|
public final V nextElement() { return next(); } |
1676 |
|
|
} |
1677 |
|
|
|
1678 |
|
|
static final class EntryIterator<K,V> extends ViewIterator<K,V> |
1679 |
|
|
implements Iterator<Map.Entry<K,V>> { |
1680 |
|
|
EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1681 |
|
|
|
1682 |
|
|
@SuppressWarnings("unchecked") |
1683 |
|
|
public final Map.Entry<K,V> next() { |
1684 |
|
|
if (next == null) |
1685 |
|
|
throw new NoSuchElementException(); |
1686 |
|
|
Object k = nextKey; |
1687 |
|
|
Object v = nextVal; |
1688 |
|
|
advance(); |
1689 |
dl |
1.24 |
return new WriteThroughEntry<K,V>((K)k, (V)v, map); |
1690 |
|
|
} |
1691 |
|
|
} |
1692 |
|
|
|
1693 |
|
|
static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V> |
1694 |
|
|
implements Iterator<Map.Entry<K,V>> { |
1695 |
|
|
SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1696 |
|
|
|
1697 |
|
|
@SuppressWarnings("unchecked") |
1698 |
|
|
public final Map.Entry<K,V> next() { |
1699 |
|
|
if (next == null) |
1700 |
|
|
throw new NoSuchElementException(); |
1701 |
|
|
Object k = nextKey; |
1702 |
|
|
Object v = nextVal; |
1703 |
|
|
advance(); |
1704 |
|
|
return new SnapshotEntry<K,V>((K)k, (V)v); |
1705 |
dl |
1.1 |
} |
1706 |
|
|
} |
1707 |
|
|
|
1708 |
|
|
/** |
1709 |
dl |
1.24 |
* Base of writeThrough and Snapshot entry classes |
1710 |
dl |
1.1 |
*/ |
1711 |
dl |
1.24 |
static abstract class MapEntry<K,V> implements Map.Entry<K, V> { |
1712 |
dl |
1.14 |
final K key; // non-null |
1713 |
|
|
V val; // non-null |
1714 |
dl |
1.24 |
MapEntry(K key, V val) { this.key = key; this.val = val; } |
1715 |
dl |
1.14 |
public final K getKey() { return key; } |
1716 |
|
|
public final V getValue() { return val; } |
1717 |
|
|
public final int hashCode() { return key.hashCode() ^ val.hashCode(); } |
1718 |
|
|
public final String toString(){ return key + "=" + val; } |
1719 |
|
|
|
1720 |
|
|
public final boolean equals(Object o) { |
1721 |
|
|
Object k, v; Map.Entry<?,?> e; |
1722 |
|
|
return ((o instanceof Map.Entry) && |
1723 |
|
|
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
1724 |
|
|
(v = e.getValue()) != null && |
1725 |
|
|
(k == key || k.equals(key)) && |
1726 |
|
|
(v == val || v.equals(val))); |
1727 |
dl |
1.1 |
} |
1728 |
|
|
|
1729 |
dl |
1.24 |
public abstract V setValue(V value); |
1730 |
|
|
} |
1731 |
|
|
|
1732 |
|
|
/** |
1733 |
|
|
* Entry used by EntryIterator.next(), that relays setValue |
1734 |
|
|
* changes to the underlying map. |
1735 |
|
|
*/ |
1736 |
|
|
static final class WriteThroughEntry<K,V> extends MapEntry<K,V> |
1737 |
|
|
implements Map.Entry<K, V> { |
1738 |
|
|
final ConcurrentHashMapV8<K, V> map; |
1739 |
|
|
WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) { |
1740 |
|
|
super(key, val); |
1741 |
|
|
this.map = map; |
1742 |
|
|
} |
1743 |
|
|
|
1744 |
dl |
1.1 |
/** |
1745 |
|
|
* Sets our entry's value and writes through to the map. The |
1746 |
|
|
* value to return is somewhat arbitrary here. Since a |
1747 |
|
|
* WriteThroughEntry does not necessarily track asynchronous |
1748 |
|
|
* changes, the most recent "previous" value could be |
1749 |
|
|
* different from what we return (or could even have been |
1750 |
|
|
* removed in which case the put will re-establish). We do not |
1751 |
|
|
* and cannot guarantee more. |
1752 |
|
|
*/ |
1753 |
dl |
1.14 |
public final V setValue(V value) { |
1754 |
dl |
1.1 |
if (value == null) throw new NullPointerException(); |
1755 |
dl |
1.14 |
V v = val; |
1756 |
|
|
val = value; |
1757 |
|
|
map.put(key, value); |
1758 |
dl |
1.1 |
return v; |
1759 |
|
|
} |
1760 |
|
|
} |
1761 |
|
|
|
1762 |
dl |
1.24 |
/** |
1763 |
|
|
* Internal version of entry, that doesn't write though changes |
1764 |
|
|
*/ |
1765 |
|
|
static final class SnapshotEntry<K,V> extends MapEntry<K,V> |
1766 |
|
|
implements Map.Entry<K, V> { |
1767 |
|
|
SnapshotEntry(K key, V val) { super(key, val); } |
1768 |
|
|
public final V setValue(V value) { // only locally update |
1769 |
|
|
if (value == null) throw new NullPointerException(); |
1770 |
|
|
V v = val; |
1771 |
|
|
val = value; |
1772 |
|
|
return v; |
1773 |
|
|
} |
1774 |
|
|
} |
1775 |
|
|
|
1776 |
dl |
1.14 |
/* ----------------Views -------------- */ |
1777 |
dl |
1.1 |
|
1778 |
dl |
1.24 |
/** |
1779 |
|
|
* Base class for views. This is done mainly to allow adding |
1780 |
|
|
* customized parallel traversals (not yet implemented.) |
1781 |
dl |
1.14 |
*/ |
1782 |
dl |
1.24 |
static abstract class MapView<K, V> { |
1783 |
dl |
1.14 |
final ConcurrentHashMapV8<K, V> map; |
1784 |
dl |
1.24 |
MapView(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
1785 |
dl |
1.14 |
public final int size() { return map.size(); } |
1786 |
|
|
public final boolean isEmpty() { return map.isEmpty(); } |
1787 |
|
|
public final void clear() { map.clear(); } |
1788 |
dl |
1.24 |
|
1789 |
|
|
// implementations below rely on concrete classes supplying these |
1790 |
|
|
abstract Iterator<?> iter(); |
1791 |
|
|
abstract public boolean contains(Object o); |
1792 |
|
|
abstract public boolean remove(Object o); |
1793 |
|
|
|
1794 |
|
|
private static final String oomeMsg = "Required array size too large"; |
1795 |
|
|
|
1796 |
|
|
public final Object[] toArray() { |
1797 |
|
|
long sz = map.longSize(); |
1798 |
|
|
if (sz > (long)(MAX_ARRAY_SIZE)) |
1799 |
|
|
throw new OutOfMemoryError(oomeMsg); |
1800 |
|
|
int n = (int)sz; |
1801 |
|
|
Object[] r = new Object[n]; |
1802 |
|
|
int i = 0; |
1803 |
|
|
Iterator<?> it = iter(); |
1804 |
|
|
while (it.hasNext()) { |
1805 |
|
|
if (i == n) { |
1806 |
|
|
if (n >= MAX_ARRAY_SIZE) |
1807 |
|
|
throw new OutOfMemoryError(oomeMsg); |
1808 |
|
|
if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) |
1809 |
|
|
n = MAX_ARRAY_SIZE; |
1810 |
|
|
else |
1811 |
|
|
n += (n >>> 1) + 1; |
1812 |
|
|
r = Arrays.copyOf(r, n); |
1813 |
|
|
} |
1814 |
|
|
r[i++] = it.next(); |
1815 |
|
|
} |
1816 |
|
|
return (i == n) ? r : Arrays.copyOf(r, i); |
1817 |
|
|
} |
1818 |
|
|
|
1819 |
|
|
@SuppressWarnings("unchecked") |
1820 |
|
|
public final <T> T[] toArray(T[] a) { |
1821 |
|
|
long sz = map.longSize(); |
1822 |
|
|
if (sz > (long)(MAX_ARRAY_SIZE)) |
1823 |
|
|
throw new OutOfMemoryError(oomeMsg); |
1824 |
|
|
int m = (int)sz; |
1825 |
|
|
T[] r = (a.length >= m) ? a : |
1826 |
|
|
(T[])java.lang.reflect.Array |
1827 |
|
|
.newInstance(a.getClass().getComponentType(), m); |
1828 |
|
|
int n = r.length; |
1829 |
|
|
int i = 0; |
1830 |
|
|
Iterator<?> it = iter(); |
1831 |
|
|
while (it.hasNext()) { |
1832 |
|
|
if (i == n) { |
1833 |
|
|
if (n >= MAX_ARRAY_SIZE) |
1834 |
|
|
throw new OutOfMemoryError(oomeMsg); |
1835 |
|
|
if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) |
1836 |
|
|
n = MAX_ARRAY_SIZE; |
1837 |
|
|
else |
1838 |
|
|
n += (n >>> 1) + 1; |
1839 |
|
|
r = Arrays.copyOf(r, n); |
1840 |
|
|
} |
1841 |
|
|
r[i++] = (T)it.next(); |
1842 |
|
|
} |
1843 |
|
|
if (a == r && i < n) { |
1844 |
|
|
r[i] = null; // null-terminate |
1845 |
|
|
return r; |
1846 |
|
|
} |
1847 |
|
|
return (i == n) ? r : Arrays.copyOf(r, i); |
1848 |
|
|
} |
1849 |
|
|
|
1850 |
|
|
public final int hashCode() { |
1851 |
|
|
int h = 0; |
1852 |
|
|
for (Iterator<?> it = iter(); it.hasNext();) |
1853 |
|
|
h += it.next().hashCode(); |
1854 |
|
|
return h; |
1855 |
|
|
} |
1856 |
|
|
|
1857 |
|
|
public final String toString() { |
1858 |
|
|
StringBuilder sb = new StringBuilder(); |
1859 |
|
|
sb.append('['); |
1860 |
|
|
Iterator<?> it = iter(); |
1861 |
|
|
if (it.hasNext()) { |
1862 |
|
|
for (;;) { |
1863 |
|
|
Object e = it.next(); |
1864 |
|
|
sb.append(e == this ? "(this Collection)" : e); |
1865 |
|
|
if (!it.hasNext()) |
1866 |
|
|
break; |
1867 |
|
|
sb.append(',').append(' '); |
1868 |
|
|
} |
1869 |
|
|
} |
1870 |
|
|
return sb.append(']').toString(); |
1871 |
|
|
} |
1872 |
|
|
|
1873 |
|
|
public final boolean containsAll(Collection<?> c) { |
1874 |
|
|
if (c != this) { |
1875 |
|
|
for (Iterator<?> it = c.iterator(); it.hasNext();) { |
1876 |
|
|
Object e = it.next(); |
1877 |
|
|
if (e == null || !contains(e)) |
1878 |
|
|
return false; |
1879 |
|
|
} |
1880 |
|
|
} |
1881 |
|
|
return true; |
1882 |
|
|
} |
1883 |
|
|
|
1884 |
|
|
public final boolean removeAll(Collection c) { |
1885 |
|
|
boolean modified = false; |
1886 |
|
|
for (Iterator<?> it = iter(); it.hasNext();) { |
1887 |
|
|
if (c.contains(it.next())) { |
1888 |
|
|
it.remove(); |
1889 |
|
|
modified = true; |
1890 |
|
|
} |
1891 |
|
|
} |
1892 |
|
|
return modified; |
1893 |
|
|
} |
1894 |
|
|
|
1895 |
|
|
public final boolean retainAll(Collection<?> c) { |
1896 |
|
|
boolean modified = false; |
1897 |
|
|
for (Iterator<?> it = iter(); it.hasNext();) { |
1898 |
|
|
if (!c.contains(it.next())) { |
1899 |
|
|
it.remove(); |
1900 |
|
|
modified = true; |
1901 |
|
|
} |
1902 |
|
|
} |
1903 |
|
|
return modified; |
1904 |
|
|
} |
1905 |
|
|
|
1906 |
|
|
} |
1907 |
|
|
|
1908 |
|
|
static final class KeySet<K,V> extends MapView<K,V> implements Set<K> { |
1909 |
|
|
KeySet(ConcurrentHashMapV8<K, V> map) { super(map); } |
1910 |
dl |
1.14 |
public final boolean contains(Object o) { return map.containsKey(o); } |
1911 |
|
|
public final boolean remove(Object o) { return map.remove(o) != null; } |
1912 |
dl |
1.24 |
|
1913 |
dl |
1.14 |
public final Iterator<K> iterator() { |
1914 |
|
|
return new KeyIterator<K,V>(map); |
1915 |
dl |
1.1 |
} |
1916 |
dl |
1.24 |
final Iterator<?> iter() { |
1917 |
|
|
return new KeyIterator<K,V>(map); |
1918 |
|
|
} |
1919 |
|
|
public final boolean add(K e) { |
1920 |
|
|
throw new UnsupportedOperationException(); |
1921 |
|
|
} |
1922 |
|
|
public final boolean addAll(Collection<? extends K> c) { |
1923 |
|
|
throw new UnsupportedOperationException(); |
1924 |
|
|
} |
1925 |
|
|
public boolean equals(Object o) { |
1926 |
|
|
Set<?> c; |
1927 |
|
|
return ((o instanceof Set) && |
1928 |
|
|
((c = (Set<?>)o) == this || |
1929 |
|
|
(containsAll(c) && c.containsAll(this)))); |
1930 |
|
|
} |
1931 |
dl |
1.1 |
} |
1932 |
|
|
|
1933 |
dl |
1.24 |
static final class Values<K,V> extends MapView<K,V> |
1934 |
|
|
implements Collection<V> { |
1935 |
|
|
Values(ConcurrentHashMapV8<K, V> map) { super(map); } |
1936 |
|
|
public final boolean contains(Object o) { return map.containsValue(o); } |
1937 |
dl |
1.14 |
|
1938 |
dl |
1.24 |
public final boolean remove(Object o) { |
1939 |
|
|
if (o != null) { |
1940 |
|
|
Iterator<V> it = new ValueIterator<K,V>(map); |
1941 |
|
|
while (it.hasNext()) { |
1942 |
|
|
if (o.equals(it.next())) { |
1943 |
|
|
it.remove(); |
1944 |
|
|
return true; |
1945 |
|
|
} |
1946 |
|
|
} |
1947 |
|
|
} |
1948 |
|
|
return false; |
1949 |
|
|
} |
1950 |
dl |
1.14 |
public final Iterator<V> iterator() { |
1951 |
|
|
return new ValueIterator<K,V>(map); |
1952 |
dl |
1.1 |
} |
1953 |
dl |
1.24 |
final Iterator<?> iter() { |
1954 |
|
|
return new ValueIterator<K,V>(map); |
1955 |
|
|
} |
1956 |
|
|
public final boolean add(V e) { |
1957 |
|
|
throw new UnsupportedOperationException(); |
1958 |
|
|
} |
1959 |
|
|
public final boolean addAll(Collection<? extends V> c) { |
1960 |
|
|
throw new UnsupportedOperationException(); |
1961 |
|
|
} |
1962 |
dl |
1.1 |
} |
1963 |
|
|
|
1964 |
dl |
1.24 |
static final class EntrySet<K,V> extends MapView<K,V> |
1965 |
|
|
implements Set<Map.Entry<K,V>> { |
1966 |
|
|
EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); } |
1967 |
dl |
1.14 |
|
1968 |
|
|
public final boolean contains(Object o) { |
1969 |
|
|
Object k, v, r; Map.Entry<?,?> e; |
1970 |
|
|
return ((o instanceof Map.Entry) && |
1971 |
|
|
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
1972 |
|
|
(r = map.get(k)) != null && |
1973 |
|
|
(v = e.getValue()) != null && |
1974 |
|
|
(v == r || v.equals(r))); |
1975 |
dl |
1.1 |
} |
1976 |
dl |
1.14 |
|
1977 |
|
|
public final boolean remove(Object o) { |
1978 |
|
|
Object k, v; Map.Entry<?,?> e; |
1979 |
|
|
return ((o instanceof Map.Entry) && |
1980 |
|
|
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
1981 |
|
|
(v = e.getValue()) != null && |
1982 |
|
|
map.remove(k, v)); |
1983 |
dl |
1.1 |
} |
1984 |
dl |
1.24 |
|
1985 |
|
|
public final Iterator<Map.Entry<K,V>> iterator() { |
1986 |
|
|
return new EntryIterator<K,V>(map); |
1987 |
|
|
} |
1988 |
|
|
final Iterator<?> iter() { |
1989 |
|
|
return new SnapshotEntryIterator<K,V>(map); |
1990 |
|
|
} |
1991 |
|
|
public final boolean add(Entry<K,V> e) { |
1992 |
|
|
throw new UnsupportedOperationException(); |
1993 |
|
|
} |
1994 |
|
|
public final boolean addAll(Collection<? extends Entry<K,V>> c) { |
1995 |
|
|
throw new UnsupportedOperationException(); |
1996 |
|
|
} |
1997 |
|
|
public boolean equals(Object o) { |
1998 |
|
|
Set<?> c; |
1999 |
|
|
return ((o instanceof Set) && |
2000 |
|
|
((c = (Set<?>)o) == this || |
2001 |
|
|
(containsAll(c) && c.containsAll(this)))); |
2002 |
|
|
} |
2003 |
dl |
1.1 |
} |
2004 |
|
|
|
2005 |
|
|
/* ---------------- Serialization Support -------------- */ |
2006 |
|
|
|
2007 |
|
|
/** |
2008 |
dl |
1.14 |
* Stripped-down version of helper class used in previous version, |
2009 |
|
|
* declared for the sake of serialization compatibility |
2010 |
dl |
1.1 |
*/ |
2011 |
dl |
1.14 |
static class Segment<K,V> implements Serializable { |
2012 |
dl |
1.1 |
private static final long serialVersionUID = 2249069246763182397L; |
2013 |
|
|
final float loadFactor; |
2014 |
|
|
Segment(float lf) { this.loadFactor = lf; } |
2015 |
|
|
} |
2016 |
|
|
|
2017 |
|
|
/** |
2018 |
|
|
* Saves the state of the {@code ConcurrentHashMapV8} instance to a |
2019 |
|
|
* stream (i.e., serializes it). |
2020 |
|
|
* @param s the stream |
2021 |
|
|
* @serialData |
2022 |
|
|
* the key (Object) and value (Object) |
2023 |
|
|
* for each key-value mapping, followed by a null pair. |
2024 |
|
|
* The key-value mappings are emitted in no particular order. |
2025 |
|
|
*/ |
2026 |
|
|
@SuppressWarnings("unchecked") |
2027 |
|
|
private void writeObject(java.io.ObjectOutputStream s) |
2028 |
|
|
throws java.io.IOException { |
2029 |
|
|
if (segments == null) { // for serialization compatibility |
2030 |
|
|
segments = (Segment<K,V>[]) |
2031 |
|
|
new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL]; |
2032 |
|
|
for (int i = 0; i < segments.length; ++i) |
2033 |
dl |
1.16 |
segments[i] = new Segment<K,V>(LOAD_FACTOR); |
2034 |
dl |
1.1 |
} |
2035 |
|
|
s.defaultWriteObject(); |
2036 |
dl |
1.14 |
InternalIterator it = new InternalIterator(table); |
2037 |
|
|
while (it.next != null) { |
2038 |
|
|
s.writeObject(it.nextKey); |
2039 |
|
|
s.writeObject(it.nextVal); |
2040 |
|
|
it.advance(); |
2041 |
|
|
} |
2042 |
dl |
1.1 |
s.writeObject(null); |
2043 |
|
|
s.writeObject(null); |
2044 |
|
|
segments = null; // throw away |
2045 |
|
|
} |
2046 |
|
|
|
2047 |
|
|
/** |
2048 |
jsr166 |
1.9 |
* Reconstitutes the instance from a stream (that is, deserializes it). |
2049 |
dl |
1.1 |
* @param s the stream |
2050 |
|
|
*/ |
2051 |
|
|
@SuppressWarnings("unchecked") |
2052 |
|
|
private void readObject(java.io.ObjectInputStream s) |
2053 |
|
|
throws java.io.IOException, ClassNotFoundException { |
2054 |
|
|
s.defaultReadObject(); |
2055 |
|
|
this.segments = null; // unneeded |
2056 |
jsr166 |
1.21 |
// initialize transient final field |
2057 |
dl |
1.14 |
UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder()); |
2058 |
|
|
|
2059 |
|
|
// Create all nodes, then place in table once size is known |
2060 |
|
|
long size = 0L; |
2061 |
|
|
Node p = null; |
2062 |
dl |
1.1 |
for (;;) { |
2063 |
dl |
1.14 |
K k = (K) s.readObject(); |
2064 |
|
|
V v = (V) s.readObject(); |
2065 |
|
|
if (k != null && v != null) { |
2066 |
|
|
p = new Node(spread(k.hashCode()), k, v, p); |
2067 |
|
|
++size; |
2068 |
|
|
} |
2069 |
|
|
else |
2070 |
dl |
1.1 |
break; |
2071 |
dl |
1.14 |
} |
2072 |
|
|
if (p != null) { |
2073 |
|
|
boolean init = false; |
2074 |
dl |
1.24 |
int n; |
2075 |
|
|
if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) |
2076 |
|
|
n = MAXIMUM_CAPACITY; |
2077 |
|
|
else { |
2078 |
|
|
int sz = (int)size; |
2079 |
|
|
n = tableSizeFor(sz + (sz >>> 1) + 1); |
2080 |
|
|
} |
2081 |
|
|
int sc = sizeCtl; |
2082 |
|
|
if (n > sc && |
2083 |
|
|
UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
2084 |
dl |
1.14 |
try { |
2085 |
|
|
if (table == null) { |
2086 |
|
|
init = true; |
2087 |
|
|
Node[] tab = new Node[n]; |
2088 |
|
|
int mask = n - 1; |
2089 |
|
|
while (p != null) { |
2090 |
|
|
int j = p.hash & mask; |
2091 |
|
|
Node next = p.next; |
2092 |
|
|
p.next = tabAt(tab, j); |
2093 |
|
|
setTabAt(tab, j, p); |
2094 |
|
|
p = next; |
2095 |
|
|
} |
2096 |
|
|
table = tab; |
2097 |
|
|
counter.add(size); |
2098 |
dl |
1.24 |
sc = n - (n >>> 2) - 1; |
2099 |
dl |
1.14 |
} |
2100 |
|
|
} finally { |
2101 |
dl |
1.24 |
sizeCtl = sc; |
2102 |
dl |
1.14 |
} |
2103 |
|
|
} |
2104 |
|
|
if (!init) { // Can only happen if unsafely published. |
2105 |
|
|
while (p != null) { |
2106 |
|
|
internalPut(p.key, p.val, true); |
2107 |
|
|
p = p.next; |
2108 |
|
|
} |
2109 |
|
|
} |
2110 |
dl |
1.1 |
} |
2111 |
|
|
} |
2112 |
|
|
|
2113 |
|
|
// Unsafe mechanics |
2114 |
|
|
private static final sun.misc.Unsafe UNSAFE; |
2115 |
|
|
private static final long counterOffset; |
2116 |
dl |
1.24 |
private static final long sizeCtlOffset; |
2117 |
dl |
1.1 |
private static final long ABASE; |
2118 |
|
|
private static final int ASHIFT; |
2119 |
|
|
|
2120 |
|
|
static { |
2121 |
|
|
int ss; |
2122 |
|
|
try { |
2123 |
|
|
UNSAFE = getUnsafe(); |
2124 |
|
|
Class<?> k = ConcurrentHashMapV8.class; |
2125 |
|
|
counterOffset = UNSAFE.objectFieldOffset |
2126 |
|
|
(k.getDeclaredField("counter")); |
2127 |
dl |
1.24 |
sizeCtlOffset = UNSAFE.objectFieldOffset |
2128 |
|
|
(k.getDeclaredField("sizeCtl")); |
2129 |
dl |
1.1 |
Class<?> sc = Node[].class; |
2130 |
|
|
ABASE = UNSAFE.arrayBaseOffset(sc); |
2131 |
|
|
ss = UNSAFE.arrayIndexScale(sc); |
2132 |
|
|
} catch (Exception e) { |
2133 |
|
|
throw new Error(e); |
2134 |
|
|
} |
2135 |
|
|
if ((ss & (ss-1)) != 0) |
2136 |
|
|
throw new Error("data type scale not a power of two"); |
2137 |
|
|
ASHIFT = 31 - Integer.numberOfLeadingZeros(ss); |
2138 |
|
|
} |
2139 |
|
|
|
2140 |
|
|
/** |
2141 |
|
|
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
2142 |
|
|
* Replace with a simple call to Unsafe.getUnsafe when integrating |
2143 |
|
|
* into a jdk. |
2144 |
|
|
* |
2145 |
|
|
* @return a sun.misc.Unsafe |
2146 |
|
|
*/ |
2147 |
|
|
private static sun.misc.Unsafe getUnsafe() { |
2148 |
|
|
try { |
2149 |
|
|
return sun.misc.Unsafe.getUnsafe(); |
2150 |
|
|
} catch (SecurityException se) { |
2151 |
|
|
try { |
2152 |
|
|
return java.security.AccessController.doPrivileged |
2153 |
|
|
(new java.security |
2154 |
|
|
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
2155 |
|
|
public sun.misc.Unsafe run() throws Exception { |
2156 |
|
|
java.lang.reflect.Field f = sun.misc |
2157 |
|
|
.Unsafe.class.getDeclaredField("theUnsafe"); |
2158 |
|
|
f.setAccessible(true); |
2159 |
|
|
return (sun.misc.Unsafe) f.get(null); |
2160 |
|
|
}}); |
2161 |
|
|
} catch (java.security.PrivilegedActionException e) { |
2162 |
|
|
throw new RuntimeException("Could not initialize intrinsics", |
2163 |
|
|
e.getCause()); |
2164 |
|
|
} |
2165 |
|
|
} |
2166 |
|
|
} |
2167 |
|
|
|
2168 |
|
|
} |