| /* |
| * Copyright (C) 2009 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
| * in compliance with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software distributed under the License |
| * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
| * or implied. See the License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| |
| package com.google.common.collect; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.collect.CollectPreconditions.checkRemove; |
| |
| import com.google.common.annotations.GwtIncompatible; |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.base.Equivalence; |
| import com.google.common.collect.MapMaker.Dummy; |
| import com.google.common.primitives.Ints; |
| import com.google.errorprone.annotations.CanIgnoreReturnValue; |
| import com.google.errorprone.annotations.concurrent.GuardedBy; |
| import com.google.j2objc.annotations.Weak; |
| import com.google.j2objc.annotations.WeakOuter; |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.Serializable; |
| import java.lang.ref.Reference; |
| import java.lang.ref.ReferenceQueue; |
| import java.lang.ref.WeakReference; |
| import java.util.AbstractCollection; |
| import java.util.AbstractMap; |
| import java.util.AbstractSet; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.NoSuchElementException; |
| import java.util.Set; |
| import java.util.concurrent.CancellationException; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.concurrent.atomic.AtomicReferenceArray; |
| import java.util.concurrent.locks.ReentrantLock; |
| import org.checkerframework.checker.nullness.compatqual.MonotonicNonNullDecl; |
| import org.checkerframework.checker.nullness.compatqual.NullableDecl; |
| |
| /** |
| * The concurrent hash map implementation built by {@link MapMaker}. |
| * |
| * <p>This implementation is heavily derived from revision 1.96 of <a |
| * href="http://tinyurl.com/ConcurrentHashMap">ConcurrentHashMap.java</a>. |
| * |
| * @param <K> the type of the keys in the map |
| * @param <V> the type of the values in the map |
| * @param <E> the type of the {@link InternalEntry} entry implementation used internally |
| * @param <S> the type of the {@link Segment} entry implementation used internally |
| * @author Bob Lee |
| * @author Charles Fry |
| * @author Doug Lea ({@code ConcurrentHashMap}) |
| */ |
| // TODO(kak/cpovirk): Consider removing @CanIgnoreReturnValue from this class. |
| @GwtIncompatible |
| @SuppressWarnings("GuardedBy") // TODO(b/35466881): Fix or suppress. |
| class MapMakerInternalMap< |
| K, |
| V, |
| E extends MapMakerInternalMap.InternalEntry<K, V, E>, |
| S extends MapMakerInternalMap.Segment<K, V, E, S>> |
| extends AbstractMap<K, V> implements ConcurrentMap<K, V>, Serializable { |
| |
| /* |
| * The basic strategy is to subdivide the table among Segments, each of which itself is a |
| * concurrently readable hash table. The map supports non-blocking reads and concurrent writes |
| * across different segments. |
| * |
| * The page replacement algorithm's data structures are kept casually consistent with the map. The |
| * ordering of writes to a segment is sequentially consistent. An update to the map and recording |
| * of reads may not be immediately reflected on the algorithm's data structures. These structures |
| * are guarded by a lock and operations are applied in batches to avoid lock contention. The |
| * penalty of applying the batches is spread across threads so that the amortized cost is slightly |
| * higher than performing just the operation without enforcing the capacity constraint. |
| * |
| * This implementation uses a per-segment queue to record a memento of the additions, removals, |
| * and accesses that were performed on the map. The queue is drained on writes and when it exceeds |
| * its capacity threshold. |
| * |
| * The Least Recently Used page replacement algorithm was chosen due to its simplicity, high hit |
| * rate, and ability to be implemented with O(1) time complexity. The initial LRU implementation |
| * operates per-segment rather than globally for increased implementation simplicity. We expect |
| * the cache hit rate to be similar to that of a global LRU algorithm. |
| */ |
| |
| // Constants |
| |
| /** |
| * The maximum capacity, used if a higher value is implicitly specified by either of the |
| * constructors with arguments. MUST be a power of two no greater than {@code 1<<30} to ensure |
| * that entries are indexable using ints. |
| */ |
| static final int MAXIMUM_CAPACITY = Ints.MAX_POWER_OF_TWO; |
| |
| /** The maximum number of segments to allow; used to bound constructor arguments. */ |
| static final int MAX_SEGMENTS = 1 << 16; // slightly conservative |
| |
| /** Number of (unsynchronized) retries in the containsValue method. */ |
| static final int CONTAINS_VALUE_RETRIES = 3; |
| |
| /** |
| * Number of cache access operations that can be buffered per segment before the cache's recency |
| * ordering information is updated. This is used to avoid lock contention by recording a memento |
| * of reads and delaying a lock acquisition until the threshold is crossed or a mutation occurs. |
| * |
| * <p>This must be a (2^n)-1 as it is used as a mask. |
| */ |
| static final int DRAIN_THRESHOLD = 0x3F; |
| |
| /** |
| * Maximum number of entries to be drained in a single cleanup run. This applies independently to |
| * the cleanup queue and both reference queues. |
| */ |
| // TODO(fry): empirically optimize this |
| static final int DRAIN_MAX = 16; |
| |
| static final long CLEANUP_EXECUTOR_DELAY_SECS = 60; |
| |
| // Fields |
| |
| /** |
| * Mask value for indexing into segments. The upper bits of a key's hash code are used to choose |
| * the segment. |
| */ |
| final transient int segmentMask; |
| |
| /** |
| * Shift value for indexing within segments. Helps prevent entries that end up in the same segment |
| * from also ending up in the same bucket. |
| */ |
| final transient int segmentShift; |
| |
| /** The segments, each of which is a specialized hash table. */ |
| final transient Segment<K, V, E, S>[] segments; |
| |
| /** The concurrency level. */ |
| final int concurrencyLevel; |
| |
| /** Strategy for comparing keys. */ |
| final Equivalence<Object> keyEquivalence; |
| |
| /** Strategy for handling entries and segments in a type-safe and efficient manner. */ |
| final transient InternalEntryHelper<K, V, E, S> entryHelper; |
| |
| /** |
| * Creates a new, empty map with the specified strategy, initial capacity and concurrency level. |
| */ |
| private MapMakerInternalMap(MapMaker builder, InternalEntryHelper<K, V, E, S> entryHelper) { |
| concurrencyLevel = Math.min(builder.getConcurrencyLevel(), MAX_SEGMENTS); |
| |
| keyEquivalence = builder.getKeyEquivalence(); |
| this.entryHelper = entryHelper; |
| |
| int initialCapacity = Math.min(builder.getInitialCapacity(), MAXIMUM_CAPACITY); |
| |
| // Find power-of-two sizes best matching arguments. Constraints: |
| // (segmentCount > concurrencyLevel) |
| int segmentShift = 0; |
| int segmentCount = 1; |
| while (segmentCount < concurrencyLevel) { |
| ++segmentShift; |
| segmentCount <<= 1; |
| } |
| this.segmentShift = 32 - segmentShift; |
| segmentMask = segmentCount - 1; |
| |
| this.segments = newSegmentArray(segmentCount); |
| |
| int segmentCapacity = initialCapacity / segmentCount; |
| if (segmentCapacity * segmentCount < initialCapacity) { |
| ++segmentCapacity; |
| } |
| |
| int segmentSize = 1; |
| while (segmentSize < segmentCapacity) { |
| segmentSize <<= 1; |
| } |
| |
| for (int i = 0; i < this.segments.length; ++i) { |
| this.segments[i] = createSegment(segmentSize, MapMaker.UNSET_INT); |
| } |
| } |
| |
| /** Returns a fresh {@link MapMakerInternalMap} as specified by the given {@code builder}. */ |
| static <K, V> MapMakerInternalMap<K, V, ? extends InternalEntry<K, V, ?>, ?> create( |
| MapMaker builder) { |
| if (builder.getKeyStrength() == Strength.STRONG |
| && builder.getValueStrength() == Strength.STRONG) { |
| return new MapMakerInternalMap<>(builder, StrongKeyStrongValueEntry.Helper.<K, V>instance()); |
| } |
| if (builder.getKeyStrength() == Strength.STRONG |
| && builder.getValueStrength() == Strength.WEAK) { |
| return new MapMakerInternalMap<>(builder, StrongKeyWeakValueEntry.Helper.<K, V>instance()); |
| } |
| if (builder.getKeyStrength() == Strength.WEAK |
| && builder.getValueStrength() == Strength.STRONG) { |
| return new MapMakerInternalMap<>(builder, WeakKeyStrongValueEntry.Helper.<K, V>instance()); |
| } |
| if (builder.getKeyStrength() == Strength.WEAK && builder.getValueStrength() == Strength.WEAK) { |
| return new MapMakerInternalMap<>(builder, WeakKeyWeakValueEntry.Helper.<K, V>instance()); |
| } |
| throw new AssertionError(); |
| } |
| |
| /** |
| * Returns a fresh {@link MapMakerInternalMap} with {@link MapMaker.Dummy} values but otherwise as |
| * specified by the given {@code builder}. The returned {@link MapMakerInternalMap} will be |
| * optimized to saved memory. Since {@link MapMaker.Dummy} is a singleton, we don't need to store |
| * any values at all. Because of this optimization, {@code build.getValueStrength()} must be |
| * {@link Strength#STRONG}. |
| * |
| * <p>This method is intended to only be used by the internal implementation of {@link Interners}, |
| * since a map of dummy values is the exact use case there. |
| */ |
| static <K> |
| MapMakerInternalMap<K, Dummy, ? extends InternalEntry<K, Dummy, ?>, ?> createWithDummyValues( |
| MapMaker builder) { |
| if (builder.getKeyStrength() == Strength.STRONG |
| && builder.getValueStrength() == Strength.STRONG) { |
| return new MapMakerInternalMap<>(builder, StrongKeyDummyValueEntry.Helper.<K>instance()); |
| } |
| if (builder.getKeyStrength() == Strength.WEAK |
| && builder.getValueStrength() == Strength.STRONG) { |
| return new MapMakerInternalMap<>(builder, WeakKeyDummyValueEntry.Helper.<K>instance()); |
| } |
| if (builder.getValueStrength() == Strength.WEAK) { |
| throw new IllegalArgumentException("Map cannot have both weak and dummy values"); |
| } |
| throw new AssertionError(); |
| } |
| |
| enum Strength { |
| STRONG { |
| @Override |
| Equivalence<Object> defaultEquivalence() { |
| return Equivalence.equals(); |
| } |
| }, |
| |
| WEAK { |
| @Override |
| Equivalence<Object> defaultEquivalence() { |
| return Equivalence.identity(); |
| } |
| }; |
| |
| /** |
| * Returns the default equivalence strategy used to compare and hash keys or values referenced |
| * at this strength. This strategy will be used unless the user explicitly specifies an |
| * alternate strategy. |
| */ |
| abstract Equivalence<Object> defaultEquivalence(); |
| } |
| |
| /** |
| * A helper object for operating on {@link InternalEntry} instances in a type-safe and efficient |
| * manner. |
| * |
| * <p>For each of the four combinations of strong/weak key and strong/weak value, there are |
| * corresponding {@link InternalEntry}, {@link Segment}, and {@link InternalEntryHelper} |
| * implementations. |
| * |
| * @param <K> the type of the key in each entry |
| * @param <V> the type of the value in each entry |
| * @param <E> the type of the {@link InternalEntry} entry implementation |
| * @param <S> the type of the {@link Segment} entry implementation |
| */ |
| interface InternalEntryHelper< |
| K, V, E extends InternalEntry<K, V, E>, S extends Segment<K, V, E, S>> { |
| /** The strength of the key type in each entry. */ |
| Strength keyStrength(); |
| |
| /** The strength of the value type in each entry. */ |
| Strength valueStrength(); |
| |
| /** Returns a freshly created segment, typed at the {@code S} type. */ |
| S newSegment(MapMakerInternalMap<K, V, E, S> map, int initialCapacity, int maxSegmentSize); |
| |
| /** |
| * Returns a freshly created entry, typed at the {@code E} type, for the given {@code segment}. |
| */ |
| E newEntry(S segment, K key, int hash, @NullableDecl E next); |
| |
| /** |
| * Returns a freshly created entry, typed at the {@code E} type, for the given {@code segment}, |
| * that is a copy of the given {@code entry}. |
| */ |
| E copy(S segment, E entry, @NullableDecl E newNext); |
| |
| /** |
| * Sets the value of the given {@code entry} in the given {@code segment} to be the given {@code |
| * value} |
| */ |
| void setValue(S segment, E entry, V value); |
| } |
| |
| /** |
| * An entry in a hash table of a {@link Segment}. |
| * |
| * <p>Entries in the map can be in the following states: |
| * |
| * <p>Valid: - Live: valid key/value are set |
| * |
| * <p>Invalid: - Collected: key/value was partially collected, but not yet cleaned up |
| */ |
| interface InternalEntry<K, V, E extends InternalEntry<K, V, E>> { |
| /** Gets the next entry in the chain. */ |
| E getNext(); |
| |
| /** Gets the entry's hash. */ |
| int getHash(); |
| |
| /** Gets the key for this entry. */ |
| K getKey(); |
| |
| /** Gets the value for the entry. */ |
| V getValue(); |
| } |
| |
| /* |
| * Note: the following classes have a lot of duplicate code. It sucks, but it saves a lot of |
| * memory. If only Java had mixins! |
| */ |
| |
| /** Base class for {@link InternalEntry} implementations for strong keys. */ |
| abstract static class AbstractStrongKeyEntry<K, V, E extends InternalEntry<K, V, E>> |
| implements InternalEntry<K, V, E> { |
| final K key; |
| final int hash; |
| @NullableDecl final E next; |
| |
| AbstractStrongKeyEntry(K key, int hash, @NullableDecl E next) { |
| this.key = key; |
| this.hash = hash; |
| this.next = next; |
| } |
| |
| @Override |
| public K getKey() { |
| return this.key; |
| } |
| |
| @Override |
| public int getHash() { |
| return hash; |
| } |
| |
| @Override |
| public E getNext() { |
| return next; |
| } |
| } |
| |
| /** Marker interface for {@link InternalEntry} implementations for strong values. */ |
| interface StrongValueEntry<K, V, E extends InternalEntry<K, V, E>> |
| extends InternalEntry<K, V, E> {} |
| |
| /** Marker interface for {@link InternalEntry} implementations for weak values. */ |
| interface WeakValueEntry<K, V, E extends InternalEntry<K, V, E>> extends InternalEntry<K, V, E> { |
| /** Gets the weak value reference held by entry. */ |
| WeakValueReference<K, V, E> getValueReference(); |
| |
| /** |
| * Clears the weak value reference held by the entry. Should be used when the entry's value is |
| * overwritten. |
| */ |
| void clearValue(); |
| } |
| |
| @SuppressWarnings("unchecked") // impl never uses a parameter or returns any non-null value |
| static <K, V, E extends InternalEntry<K, V, E>> |
| WeakValueReference<K, V, E> unsetWeakValueReference() { |
| return (WeakValueReference<K, V, E>) UNSET_WEAK_VALUE_REFERENCE; |
| } |
| |
| /** Concrete implementation of {@link InternalEntry} for strong keys and strong values. */ |
| static final class StrongKeyStrongValueEntry<K, V> |
| extends AbstractStrongKeyEntry<K, V, StrongKeyStrongValueEntry<K, V>> |
| implements StrongValueEntry<K, V, StrongKeyStrongValueEntry<K, V>> { |
| @NullableDecl private volatile V value = null; |
| |
| StrongKeyStrongValueEntry(K key, int hash, @NullableDecl StrongKeyStrongValueEntry<K, V> next) { |
| super(key, hash, next); |
| } |
| |
| @Override |
| @NullableDecl |
| public V getValue() { |
| return value; |
| } |
| |
| void setValue(V value) { |
| this.value = value; |
| } |
| |
| StrongKeyStrongValueEntry<K, V> copy(StrongKeyStrongValueEntry<K, V> newNext) { |
| StrongKeyStrongValueEntry<K, V> newEntry = |
| new StrongKeyStrongValueEntry<>(this.key, this.hash, newNext); |
| newEntry.value = this.value; |
| return newEntry; |
| } |
| |
| /** Concrete implementation of {@link InternalEntryHelper} for strong keys and strong values. */ |
| static final class Helper<K, V> |
| implements InternalEntryHelper< |
| K, V, StrongKeyStrongValueEntry<K, V>, StrongKeyStrongValueSegment<K, V>> { |
| private static final Helper<?, ?> INSTANCE = new Helper<>(); |
| |
| @SuppressWarnings("unchecked") |
| static <K, V> Helper<K, V> instance() { |
| return (Helper<K, V>) INSTANCE; |
| } |
| |
| @Override |
| public Strength keyStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public Strength valueStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public StrongKeyStrongValueSegment<K, V> newSegment( |
| MapMakerInternalMap< |
| K, V, StrongKeyStrongValueEntry<K, V>, StrongKeyStrongValueSegment<K, V>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| return new StrongKeyStrongValueSegment<>(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| public StrongKeyStrongValueEntry<K, V> copy( |
| StrongKeyStrongValueSegment<K, V> segment, |
| StrongKeyStrongValueEntry<K, V> entry, |
| @NullableDecl StrongKeyStrongValueEntry<K, V> newNext) { |
| return entry.copy(newNext); |
| } |
| |
| @Override |
| public void setValue( |
| StrongKeyStrongValueSegment<K, V> segment, |
| StrongKeyStrongValueEntry<K, V> entry, |
| V value) { |
| entry.setValue(value); |
| } |
| |
| @Override |
| public StrongKeyStrongValueEntry<K, V> newEntry( |
| StrongKeyStrongValueSegment<K, V> segment, |
| K key, |
| int hash, |
| @NullableDecl StrongKeyStrongValueEntry<K, V> next) { |
| return new StrongKeyStrongValueEntry<>(key, hash, next); |
| } |
| } |
| } |
| |
| /** Concrete implementation of {@link InternalEntry} for strong keys and weak values. */ |
| static final class StrongKeyWeakValueEntry<K, V> |
| extends AbstractStrongKeyEntry<K, V, StrongKeyWeakValueEntry<K, V>> |
| implements WeakValueEntry<K, V, StrongKeyWeakValueEntry<K, V>> { |
| private volatile WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> valueReference = |
| unsetWeakValueReference(); |
| |
| StrongKeyWeakValueEntry(K key, int hash, @NullableDecl StrongKeyWeakValueEntry<K, V> next) { |
| super(key, hash, next); |
| } |
| |
| @Override |
| public V getValue() { |
| return valueReference.get(); |
| } |
| |
| @Override |
| public void clearValue() { |
| valueReference.clear(); |
| } |
| |
| void setValue(V value, ReferenceQueue<V> queueForValues) { |
| WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> previous = this.valueReference; |
| this.valueReference = new WeakValueReferenceImpl<>(queueForValues, value, this); |
| previous.clear(); |
| } |
| |
| StrongKeyWeakValueEntry<K, V> copy( |
| ReferenceQueue<V> queueForValues, StrongKeyWeakValueEntry<K, V> newNext) { |
| StrongKeyWeakValueEntry<K, V> newEntry = new StrongKeyWeakValueEntry<>(key, hash, newNext); |
| newEntry.valueReference = valueReference.copyFor(queueForValues, newEntry); |
| return newEntry; |
| } |
| |
| @Override |
| public WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> getValueReference() { |
| return valueReference; |
| } |
| |
| /** Concrete implementation of {@link InternalEntryHelper} for strong keys and weak values. */ |
| static final class Helper<K, V> |
| implements InternalEntryHelper< |
| K, V, StrongKeyWeakValueEntry<K, V>, StrongKeyWeakValueSegment<K, V>> { |
| private static final Helper<?, ?> INSTANCE = new Helper<>(); |
| |
| @SuppressWarnings("unchecked") |
| static <K, V> Helper<K, V> instance() { |
| return (Helper<K, V>) INSTANCE; |
| } |
| |
| @Override |
| public Strength keyStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public Strength valueStrength() { |
| return Strength.WEAK; |
| } |
| |
| @Override |
| public StrongKeyWeakValueSegment<K, V> newSegment( |
| MapMakerInternalMap<K, V, StrongKeyWeakValueEntry<K, V>, StrongKeyWeakValueSegment<K, V>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| return new StrongKeyWeakValueSegment<>(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| public StrongKeyWeakValueEntry<K, V> copy( |
| StrongKeyWeakValueSegment<K, V> segment, |
| StrongKeyWeakValueEntry<K, V> entry, |
| @NullableDecl StrongKeyWeakValueEntry<K, V> newNext) { |
| if (Segment.isCollected(entry)) { |
| return null; |
| } |
| return entry.copy(segment.queueForValues, newNext); |
| } |
| |
| @Override |
| public void setValue( |
| StrongKeyWeakValueSegment<K, V> segment, StrongKeyWeakValueEntry<K, V> entry, V value) { |
| entry.setValue(value, segment.queueForValues); |
| } |
| |
| @Override |
| public StrongKeyWeakValueEntry<K, V> newEntry( |
| StrongKeyWeakValueSegment<K, V> segment, |
| K key, |
| int hash, |
| @NullableDecl StrongKeyWeakValueEntry<K, V> next) { |
| return new StrongKeyWeakValueEntry<>(key, hash, next); |
| } |
| } |
| } |
| |
| /** Concrete implementation of {@link InternalEntry} for strong keys and {@link Dummy} values. */ |
| static final class StrongKeyDummyValueEntry<K> |
| extends AbstractStrongKeyEntry<K, Dummy, StrongKeyDummyValueEntry<K>> |
| implements StrongValueEntry<K, Dummy, StrongKeyDummyValueEntry<K>> { |
| StrongKeyDummyValueEntry(K key, int hash, @NullableDecl StrongKeyDummyValueEntry<K> next) { |
| super(key, hash, next); |
| } |
| |
| @Override |
| public Dummy getValue() { |
| return Dummy.VALUE; |
| } |
| |
| void setValue(Dummy value) {} |
| |
| StrongKeyDummyValueEntry<K> copy(StrongKeyDummyValueEntry<K> newNext) { |
| return new StrongKeyDummyValueEntry<K>(this.key, this.hash, newNext); |
| } |
| |
| /** |
| * Concrete implementation of {@link InternalEntryHelper} for strong keys and {@link Dummy} |
| * values. |
| */ |
| static final class Helper<K> |
| implements InternalEntryHelper< |
| K, Dummy, StrongKeyDummyValueEntry<K>, StrongKeyDummyValueSegment<K>> { |
| private static final Helper<?> INSTANCE = new Helper<>(); |
| |
| @SuppressWarnings("unchecked") |
| static <K> Helper<K> instance() { |
| return (Helper<K>) INSTANCE; |
| } |
| |
| @Override |
| public Strength keyStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public Strength valueStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public StrongKeyDummyValueSegment<K> newSegment( |
| MapMakerInternalMap<K, Dummy, StrongKeyDummyValueEntry<K>, StrongKeyDummyValueSegment<K>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| return new StrongKeyDummyValueSegment<K>(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| public StrongKeyDummyValueEntry<K> copy( |
| StrongKeyDummyValueSegment<K> segment, |
| StrongKeyDummyValueEntry<K> entry, |
| @NullableDecl StrongKeyDummyValueEntry<K> newNext) { |
| return entry.copy(newNext); |
| } |
| |
| @Override |
| public void setValue( |
| StrongKeyDummyValueSegment<K> segment, StrongKeyDummyValueEntry<K> entry, Dummy value) {} |
| |
| @Override |
| public StrongKeyDummyValueEntry<K> newEntry( |
| StrongKeyDummyValueSegment<K> segment, |
| K key, |
| int hash, |
| @NullableDecl StrongKeyDummyValueEntry<K> next) { |
| return new StrongKeyDummyValueEntry<K>(key, hash, next); |
| } |
| } |
| } |
| |
| /** Base class for {@link InternalEntry} implementations for weak keys. */ |
| abstract static class AbstractWeakKeyEntry<K, V, E extends InternalEntry<K, V, E>> |
| extends WeakReference<K> implements InternalEntry<K, V, E> { |
| final int hash; |
| @NullableDecl final E next; |
| |
| AbstractWeakKeyEntry(ReferenceQueue<K> queue, K key, int hash, @NullableDecl E next) { |
| super(key, queue); |
| this.hash = hash; |
| this.next = next; |
| } |
| |
| @Override |
| public K getKey() { |
| return get(); |
| } |
| |
| @Override |
| public int getHash() { |
| return hash; |
| } |
| |
| @Override |
| public E getNext() { |
| return next; |
| } |
| } |
| |
| /** Concrete implementation of {@link InternalEntry} for weak keys and {@link Dummy} values. */ |
| static final class WeakKeyDummyValueEntry<K> |
| extends AbstractWeakKeyEntry<K, Dummy, WeakKeyDummyValueEntry<K>> |
| implements StrongValueEntry<K, Dummy, WeakKeyDummyValueEntry<K>> { |
| WeakKeyDummyValueEntry( |
| ReferenceQueue<K> queue, K key, int hash, @NullableDecl WeakKeyDummyValueEntry<K> next) { |
| super(queue, key, hash, next); |
| } |
| |
| @Override |
| public Dummy getValue() { |
| return Dummy.VALUE; |
| } |
| |
| void setValue(Dummy value) {} |
| |
| WeakKeyDummyValueEntry<K> copy( |
| ReferenceQueue<K> queueForKeys, WeakKeyDummyValueEntry<K> newNext) { |
| return new WeakKeyDummyValueEntry<K>(queueForKeys, getKey(), this.hash, newNext); |
| } |
| |
| /** |
| * Concrete implementation of {@link InternalEntryHelper} for weak keys and {@link Dummy} |
| * values. |
| */ |
| static final class Helper<K> |
| implements InternalEntryHelper< |
| K, Dummy, WeakKeyDummyValueEntry<K>, WeakKeyDummyValueSegment<K>> { |
| private static final Helper<?> INSTANCE = new Helper<>(); |
| |
| @SuppressWarnings("unchecked") |
| static <K> Helper<K> instance() { |
| return (Helper<K>) INSTANCE; |
| } |
| |
| @Override |
| public Strength keyStrength() { |
| return Strength.WEAK; |
| } |
| |
| @Override |
| public Strength valueStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public WeakKeyDummyValueSegment<K> newSegment( |
| MapMakerInternalMap<K, Dummy, WeakKeyDummyValueEntry<K>, WeakKeyDummyValueSegment<K>> map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| return new WeakKeyDummyValueSegment<K>(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| public WeakKeyDummyValueEntry<K> copy( |
| WeakKeyDummyValueSegment<K> segment, |
| WeakKeyDummyValueEntry<K> entry, |
| @NullableDecl WeakKeyDummyValueEntry<K> newNext) { |
| if (entry.getKey() == null) { |
| // key collected |
| return null; |
| } |
| return entry.copy(segment.queueForKeys, newNext); |
| } |
| |
| @Override |
| public void setValue( |
| WeakKeyDummyValueSegment<K> segment, WeakKeyDummyValueEntry<K> entry, Dummy value) {} |
| |
| @Override |
| public WeakKeyDummyValueEntry<K> newEntry( |
| WeakKeyDummyValueSegment<K> segment, |
| K key, |
| int hash, |
| @NullableDecl WeakKeyDummyValueEntry<K> next) { |
| return new WeakKeyDummyValueEntry<K>(segment.queueForKeys, key, hash, next); |
| } |
| } |
| } |
| |
| /** Concrete implementation of {@link InternalEntry} for weak keys and strong values. */ |
| static final class WeakKeyStrongValueEntry<K, V> |
| extends AbstractWeakKeyEntry<K, V, WeakKeyStrongValueEntry<K, V>> |
| implements StrongValueEntry<K, V, WeakKeyStrongValueEntry<K, V>> { |
| @NullableDecl private volatile V value = null; |
| |
| WeakKeyStrongValueEntry( |
| ReferenceQueue<K> queue, |
| K key, |
| int hash, |
| @NullableDecl WeakKeyStrongValueEntry<K, V> next) { |
| super(queue, key, hash, next); |
| } |
| |
| @Override |
| @NullableDecl |
| public V getValue() { |
| return value; |
| } |
| |
| void setValue(V value) { |
| this.value = value; |
| } |
| |
| WeakKeyStrongValueEntry<K, V> copy( |
| ReferenceQueue<K> queueForKeys, WeakKeyStrongValueEntry<K, V> newNext) { |
| WeakKeyStrongValueEntry<K, V> newEntry = |
| new WeakKeyStrongValueEntry<>(queueForKeys, getKey(), this.hash, newNext); |
| newEntry.setValue(value); |
| return newEntry; |
| } |
| |
| /** Concrete implementation of {@link InternalEntryHelper} for weak keys and strong values. */ |
| static final class Helper<K, V> |
| implements InternalEntryHelper< |
| K, V, WeakKeyStrongValueEntry<K, V>, WeakKeyStrongValueSegment<K, V>> { |
| private static final Helper<?, ?> INSTANCE = new Helper<>(); |
| |
| @SuppressWarnings("unchecked") |
| static <K, V> Helper<K, V> instance() { |
| return (Helper<K, V>) INSTANCE; |
| } |
| |
| @Override |
| public Strength keyStrength() { |
| return Strength.WEAK; |
| } |
| |
| @Override |
| public Strength valueStrength() { |
| return Strength.STRONG; |
| } |
| |
| @Override |
| public WeakKeyStrongValueSegment<K, V> newSegment( |
| MapMakerInternalMap<K, V, WeakKeyStrongValueEntry<K, V>, WeakKeyStrongValueSegment<K, V>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| return new WeakKeyStrongValueSegment<>(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| public WeakKeyStrongValueEntry<K, V> copy( |
| WeakKeyStrongValueSegment<K, V> segment, |
| WeakKeyStrongValueEntry<K, V> entry, |
| @NullableDecl WeakKeyStrongValueEntry<K, V> newNext) { |
| if (entry.getKey() == null) { |
| // key collected |
| return null; |
| } |
| return entry.copy(segment.queueForKeys, newNext); |
| } |
| |
| @Override |
| public void setValue( |
| WeakKeyStrongValueSegment<K, V> segment, WeakKeyStrongValueEntry<K, V> entry, V value) { |
| entry.setValue(value); |
| } |
| |
| @Override |
| public WeakKeyStrongValueEntry<K, V> newEntry( |
| WeakKeyStrongValueSegment<K, V> segment, |
| K key, |
| int hash, |
| @NullableDecl WeakKeyStrongValueEntry<K, V> next) { |
| return new WeakKeyStrongValueEntry<>(segment.queueForKeys, key, hash, next); |
| } |
| } |
| } |
| |
| /** Concrete implementation of {@link InternalEntry} for weak keys and weak values. */ |
| static final class WeakKeyWeakValueEntry<K, V> |
| extends AbstractWeakKeyEntry<K, V, WeakKeyWeakValueEntry<K, V>> |
| implements WeakValueEntry<K, V, WeakKeyWeakValueEntry<K, V>> { |
| private volatile WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> valueReference = |
| unsetWeakValueReference(); |
| |
| WeakKeyWeakValueEntry( |
| ReferenceQueue<K> queue, K key, int hash, @NullableDecl WeakKeyWeakValueEntry<K, V> next) { |
| super(queue, key, hash, next); |
| } |
| |
| @Override |
| public V getValue() { |
| return valueReference.get(); |
| } |
| |
| WeakKeyWeakValueEntry<K, V> copy( |
| ReferenceQueue<K> queueForKeys, |
| ReferenceQueue<V> queueForValues, |
| WeakKeyWeakValueEntry<K, V> newNext) { |
| WeakKeyWeakValueEntry<K, V> newEntry = |
| new WeakKeyWeakValueEntry<>(queueForKeys, getKey(), this.hash, newNext); |
| newEntry.valueReference = valueReference.copyFor(queueForValues, newEntry); |
| return newEntry; |
| } |
| |
| @Override |
| public void clearValue() { |
| valueReference.clear(); |
| } |
| |
| void setValue(V value, ReferenceQueue<V> queueForValues) { |
| WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> previous = this.valueReference; |
| this.valueReference = new WeakValueReferenceImpl<>(queueForValues, value, this); |
| previous.clear(); |
| } |
| |
| @Override |
| public WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> getValueReference() { |
| return valueReference; |
| } |
| |
| /** Concrete implementation of {@link InternalEntryHelper} for weak keys and weak values. */ |
| static final class Helper<K, V> |
| implements InternalEntryHelper< |
| K, V, WeakKeyWeakValueEntry<K, V>, WeakKeyWeakValueSegment<K, V>> { |
| private static final Helper<?, ?> INSTANCE = new Helper<>(); |
| |
| @SuppressWarnings("unchecked") |
| static <K, V> Helper<K, V> instance() { |
| return (Helper<K, V>) INSTANCE; |
| } |
| |
| @Override |
| public Strength keyStrength() { |
| return Strength.WEAK; |
| } |
| |
| @Override |
| public Strength valueStrength() { |
| return Strength.WEAK; |
| } |
| |
| @Override |
| public WeakKeyWeakValueSegment<K, V> newSegment( |
| MapMakerInternalMap<K, V, WeakKeyWeakValueEntry<K, V>, WeakKeyWeakValueSegment<K, V>> map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| return new WeakKeyWeakValueSegment<>(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| public WeakKeyWeakValueEntry<K, V> copy( |
| WeakKeyWeakValueSegment<K, V> segment, |
| WeakKeyWeakValueEntry<K, V> entry, |
| @NullableDecl WeakKeyWeakValueEntry<K, V> newNext) { |
| if (entry.getKey() == null) { |
| // key collected |
| return null; |
| } |
| if (Segment.isCollected(entry)) { |
| return null; |
| } |
| return entry.copy(segment.queueForKeys, segment.queueForValues, newNext); |
| } |
| |
| @Override |
| public void setValue( |
| WeakKeyWeakValueSegment<K, V> segment, WeakKeyWeakValueEntry<K, V> entry, V value) { |
| entry.setValue(value, segment.queueForValues); |
| } |
| |
| @Override |
| public WeakKeyWeakValueEntry<K, V> newEntry( |
| WeakKeyWeakValueSegment<K, V> segment, |
| K key, |
| int hash, |
| @NullableDecl WeakKeyWeakValueEntry<K, V> next) { |
| return new WeakKeyWeakValueEntry<>(segment.queueForKeys, key, hash, next); |
| } |
| } |
| } |
| |
| /** A weakly referenced value that also has a reference to its containing entry. */ |
| interface WeakValueReference<K, V, E extends InternalEntry<K, V, E>> { |
| /** |
| * Returns the current value being referenced, or {@code null} if there is none (e.g. because |
| * either it got collected, or {@link #clear} was called, or it wasn't set in the first place). |
| */ |
| @NullableDecl |
| V get(); |
| |
| /** Returns the entry which contains this {@link WeakValueReference}. */ |
| E getEntry(); |
| |
| /** Unsets the referenced value. Subsequent calls to {@link #get} will return {@code null}. */ |
| void clear(); |
| |
| /** |
| * Returns a freshly created {@link WeakValueReference} for the given {@code entry} (and on the |
| * given {@code queue} with the same value as this {@link WeakValueReference}. |
| */ |
| WeakValueReference<K, V, E> copyFor(ReferenceQueue<V> queue, E entry); |
| } |
| |
| /** |
| * A dummy implementation of {@link InternalEntry}, solely for use in the type signature of {@link |
| * #UNSET_WEAK_VALUE_REFERENCE} below. |
| */ |
| static final class DummyInternalEntry |
| implements InternalEntry<Object, Object, DummyInternalEntry> { |
| private DummyInternalEntry() { |
| throw new AssertionError(); |
| } |
| |
| @Override |
| public DummyInternalEntry getNext() { |
| throw new AssertionError(); |
| } |
| |
| @Override |
| public int getHash() { |
| throw new AssertionError(); |
| } |
| |
| @Override |
| public Object getKey() { |
| throw new AssertionError(); |
| } |
| |
| @Override |
| public Object getValue() { |
| throw new AssertionError(); |
| } |
| } |
| |
| /** |
| * A singleton {@link WeakValueReference} used to denote an unset value in a entry with weak |
| * values. |
| */ |
| static final WeakValueReference<Object, Object, DummyInternalEntry> UNSET_WEAK_VALUE_REFERENCE = |
| new WeakValueReference<Object, Object, DummyInternalEntry>() { |
| @Override |
| public DummyInternalEntry getEntry() { |
| return null; |
| } |
| |
| @Override |
| public void clear() {} |
| |
| @Override |
| public Object get() { |
| return null; |
| } |
| |
| @Override |
| public WeakValueReference<Object, Object, DummyInternalEntry> copyFor( |
| ReferenceQueue<Object> queue, DummyInternalEntry entry) { |
| return this; |
| } |
| }; |
| |
| /** Concrete implementation of {@link WeakValueReference}. */ |
| static final class WeakValueReferenceImpl<K, V, E extends InternalEntry<K, V, E>> |
| extends WeakReference<V> implements WeakValueReference<K, V, E> { |
| @Weak final E entry; |
| |
| WeakValueReferenceImpl(ReferenceQueue<V> queue, V referent, E entry) { |
| super(referent, queue); |
| this.entry = entry; |
| } |
| |
| @Override |
| public E getEntry() { |
| return entry; |
| } |
| |
| @Override |
| public WeakValueReference<K, V, E> copyFor(ReferenceQueue<V> queue, E entry) { |
| return new WeakValueReferenceImpl<>(queue, get(), entry); |
| } |
| } |
| |
| /** |
| * Applies a supplemental hash function to a given hash code, which defends against poor quality |
| * hash functions. This is critical when the concurrent hash map uses power-of-two length hash |
| * tables, that otherwise encounter collisions for hash codes that do not differ in lower or upper |
| * bits. |
| * |
| * @param h hash code |
| */ |
| static int rehash(int h) { |
| // Spread bits to regularize both segment and index locations, |
| // using variant of single-word Wang/Jenkins hash. |
| // TODO(kevinb): use Hashing/move this to Hashing? |
| h += (h << 15) ^ 0xffffcd7d; |
| h ^= (h >>> 10); |
| h += (h << 3); |
| h ^= (h >>> 6); |
| h += (h << 2) + (h << 14); |
| return h ^ (h >>> 16); |
| } |
| |
| /** |
| * This method is a convenience for testing. Code should call {@link Segment#copyEntry} directly. |
| */ |
| // Guarded By Segment.this |
| @VisibleForTesting |
| E copyEntry(E original, E newNext) { |
| int hash = original.getHash(); |
| return segmentFor(hash).copyEntry(original, newNext); |
| } |
| |
| int hash(Object key) { |
| int h = keyEquivalence.hash(key); |
| return rehash(h); |
| } |
| |
| void reclaimValue(WeakValueReference<K, V, E> valueReference) { |
| E entry = valueReference.getEntry(); |
| int hash = entry.getHash(); |
| segmentFor(hash).reclaimValue(entry.getKey(), hash, valueReference); |
| } |
| |
| void reclaimKey(E entry) { |
| int hash = entry.getHash(); |
| segmentFor(hash).reclaimKey(entry, hash); |
| } |
| |
| /** |
| * This method is a convenience for testing. Code should call {@link Segment#getLiveValue} |
| * instead. |
| */ |
| @VisibleForTesting |
| boolean isLiveForTesting(InternalEntry<K, V, ?> entry) { |
| return segmentFor(entry.getHash()).getLiveValueForTesting(entry) != null; |
| } |
| |
| /** |
| * Returns the segment that should be used for a key with the given hash. |
| * |
| * @param hash the hash code for the key |
| * @return the segment |
| */ |
| Segment<K, V, E, S> segmentFor(int hash) { |
| // TODO(fry): Lazily create segments? |
| return segments[(hash >>> segmentShift) & segmentMask]; |
| } |
| |
| Segment<K, V, E, S> createSegment(int initialCapacity, int maxSegmentSize) { |
| return entryHelper.newSegment(this, initialCapacity, maxSegmentSize); |
| } |
| |
| /** |
| * Gets the value from an entry. Returns {@code null} if the entry is invalid, partially-collected |
| * or computing. |
| */ |
| V getLiveValue(E entry) { |
| if (entry.getKey() == null) { |
| return null; |
| } |
| V value = entry.getValue(); |
| if (value == null) { |
| return null; |
| } |
| return value; |
| } |
| |
| @SuppressWarnings("unchecked") |
| final Segment<K, V, E, S>[] newSegmentArray(int ssize) { |
| return new Segment[ssize]; |
| } |
| |
| // Inner Classes |
| |
| /** |
| * Segments are specialized versions of hash tables. This subclass inherits from ReentrantLock |
| * opportunistically, just to simplify some locking and avoid separate construction. |
| */ |
| @SuppressWarnings("serial") // This class is never serialized. |
| abstract static class Segment< |
| K, V, E extends InternalEntry<K, V, E>, S extends Segment<K, V, E, S>> |
| extends ReentrantLock { |
| |
| /* |
| * Segments maintain a table of entry lists that are ALWAYS kept in a consistent state, so can |
| * be read without locking. Next fields of nodes are immutable (final). All list additions are |
| * performed at the front of each bin. This makes it easy to check changes, and also fast to |
| * traverse. When nodes would otherwise be changed, new nodes are created to replace them. This |
| * works well for hash tables since the bin lists tend to be short. (The average length is less |
| * than two.) |
| * |
| * Read operations can thus proceed without locking, but rely on selected uses of volatiles to |
| * ensure that completed write operations performed by other threads are noticed. For most |
| * purposes, the "count" field, tracking the number of elements, serves as that volatile |
| * variable ensuring visibility. This is convenient because this field needs to be read in many |
| * read operations anyway: |
| * |
| * - All (unsynchronized) read operations must first read the "count" field, and should not |
| * look at table entries if it is 0. |
| * |
| * - All (synchronized) write operations should write to the "count" field after structurally |
| * changing any bin. The operations must not take any action that could even momentarily |
| * cause a concurrent read operation to see inconsistent data. This is made easier by the |
| * nature of the read operations in Map. For example, no operation can reveal that the table |
| * has grown but the threshold has not yet been updated, so there are no atomicity requirements |
| * for this with respect to reads. |
| * |
| * As a guide, all critical volatile reads and writes to the count field are marked in code |
| * comments. |
| */ |
| |
| @Weak final MapMakerInternalMap<K, V, E, S> map; |
| |
| /** |
| * The number of live elements in this segment's region. This does not include unset elements |
| * which are awaiting cleanup. |
| */ |
| volatile int count; |
| |
| /** |
| * Number of updates that alter the size of the table. This is used during bulk-read methods to |
| * make sure they see a consistent snapshot: If modCounts change during a traversal of segments |
| * computing size or checking containsValue, then we might have an inconsistent view of state so |
| * (usually) must retry. |
| */ |
| int modCount; |
| |
| /** |
| * The table is expanded when its size exceeds this threshold. (The value of this field is |
| * always {@code (int) (capacity * 0.75)}.) |
| */ |
| int threshold; |
| |
| /** The per-segment table. */ |
| @MonotonicNonNullDecl volatile AtomicReferenceArray<E> table; |
| |
| /** The maximum size of this map. MapMaker.UNSET_INT if there is no maximum. */ |
| final int maxSegmentSize; |
| |
| /** |
| * A counter of the number of reads since the last write, used to drain queues on a small |
| * fraction of read operations. |
| */ |
| final AtomicInteger readCount = new AtomicInteger(); |
| |
| Segment(MapMakerInternalMap<K, V, E, S> map, int initialCapacity, int maxSegmentSize) { |
| this.map = map; |
| this.maxSegmentSize = maxSegmentSize; |
| initTable(newEntryArray(initialCapacity)); |
| } |
| |
| /** |
| * Returns {@code this} up-casted to the specific {@link Segment} implementation type {@code S}. |
| * |
| * <p>This method exists so that the {@link Segment} code can be generic in terms of {@code S}, |
| * the type of the concrete implementation. |
| */ |
| abstract S self(); |
| |
| /** Drains the reference queues used by this segment, if any. */ |
| @GuardedBy("this") |
| void maybeDrainReferenceQueues() {} |
| |
| /** Clears the reference queues used by this segment, if any. */ |
| void maybeClearReferenceQueues() {} |
| |
| /** Sets the value of the given {@code entry}. */ |
| void setValue(E entry, V value) { |
| this.map.entryHelper.setValue(self(), entry, value); |
| } |
| |
| /** Returns a copy of the given {@code entry}. */ |
| E copyEntry(E original, E newNext) { |
| return this.map.entryHelper.copy(self(), original, newNext); |
| } |
| |
| AtomicReferenceArray<E> newEntryArray(int size) { |
| return new AtomicReferenceArray<E>(size); |
| } |
| |
| void initTable(AtomicReferenceArray<E> newTable) { |
| this.threshold = newTable.length() * 3 / 4; // 0.75 |
| if (this.threshold == maxSegmentSize) { |
| // prevent spurious expansion before eviction |
| this.threshold++; |
| } |
| this.table = newTable; |
| } |
| |
| // Convenience methods for testing |
| |
| /** |
| * Unsafe cast of the given entry to {@code E}, the type of the specific {@link InternalEntry} |
| * implementation type. |
| * |
| * <p>This method is provided as a convenience for tests. Otherwise they'd need to be |
| * knowledgable about all the implementation details of our type system trickery. |
| */ |
| abstract E castForTesting(InternalEntry<K, V, ?> entry); |
| |
| /** Unsafely extracts the key reference queue used by this segment. */ |
| ReferenceQueue<K> getKeyReferenceQueueForTesting() { |
| throw new AssertionError(); |
| } |
| |
| /** Unsafely extracts the value reference queue used by this segment. */ |
| ReferenceQueue<V> getValueReferenceQueueForTesting() { |
| throw new AssertionError(); |
| } |
| |
| /** Unsafely extracts the weak value reference inside of the given {@code entry}. */ |
| WeakValueReference<K, V, E> getWeakValueReferenceForTesting(InternalEntry<K, V, ?> entry) { |
| throw new AssertionError(); |
| } |
| |
| /** |
| * Unsafely creates of a fresh {@link WeakValueReference}, referencing the given {@code value}, |
| * for the given {@code entry} |
| */ |
| WeakValueReference<K, V, E> newWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> entry, V value) { |
| throw new AssertionError(); |
| } |
| |
| /** |
| * Unsafely sets the weak value reference inside the given {@code entry} to be the given {@code |
| * valueReference} |
| */ |
| void setWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> entry, |
| WeakValueReference<K, V, ? extends InternalEntry<K, V, ?>> valueReference) { |
| throw new AssertionError(); |
| } |
| |
| /** |
| * Unsafely sets the given index of this segment's internal hash table to be the given entry. |
| */ |
| void setTableEntryForTesting(int i, InternalEntry<K, V, ?> entry) { |
| table.set(i, castForTesting(entry)); |
| } |
| |
| /** Unsafely returns a copy of the given entry. */ |
| E copyForTesting(InternalEntry<K, V, ?> entry, @NullableDecl InternalEntry<K, V, ?> newNext) { |
| return this.map.entryHelper.copy(self(), castForTesting(entry), castForTesting(newNext)); |
| } |
| |
| /** Unsafely sets the value of the given entry. */ |
| void setValueForTesting(InternalEntry<K, V, ?> entry, V value) { |
| this.map.entryHelper.setValue(self(), castForTesting(entry), value); |
| } |
| |
| /** Unsafely returns a fresh entry. */ |
| E newEntryForTesting(K key, int hash, @NullableDecl InternalEntry<K, V, ?> next) { |
| return this.map.entryHelper.newEntry(self(), key, hash, castForTesting(next)); |
| } |
| |
| /** Unsafely removes the given entry from this segment's hash table. */ |
| @CanIgnoreReturnValue |
| boolean removeTableEntryForTesting(InternalEntry<K, V, ?> entry) { |
| return removeEntryForTesting(castForTesting(entry)); |
| } |
| |
| /** Unsafely removes the given entry from the given chain in this segment's hash table. */ |
| E removeFromChainForTesting(InternalEntry<K, V, ?> first, InternalEntry<K, V, ?> entry) { |
| return removeFromChain(castForTesting(first), castForTesting(entry)); |
| } |
| |
| /** |
| * Unsafely returns the value of the given entry if it's still live, or {@code null} otherwise. |
| */ |
| @NullableDecl |
| V getLiveValueForTesting(InternalEntry<K, V, ?> entry) { |
| return getLiveValue(castForTesting(entry)); |
| } |
| |
| // reference queues, for garbage collection cleanup |
| |
| /** Cleanup collected entries when the lock is available. */ |
| void tryDrainReferenceQueues() { |
| if (tryLock()) { |
| try { |
| maybeDrainReferenceQueues(); |
| } finally { |
| unlock(); |
| } |
| } |
| } |
| |
| @GuardedBy("this") |
| void drainKeyReferenceQueue(ReferenceQueue<K> keyReferenceQueue) { |
| Reference<? extends K> ref; |
| int i = 0; |
| while ((ref = keyReferenceQueue.poll()) != null) { |
| @SuppressWarnings("unchecked") |
| E entry = (E) ref; |
| map.reclaimKey(entry); |
| if (++i == DRAIN_MAX) { |
| break; |
| } |
| } |
| } |
| |
| @GuardedBy("this") |
| void drainValueReferenceQueue(ReferenceQueue<V> valueReferenceQueue) { |
| Reference<? extends V> ref; |
| int i = 0; |
| while ((ref = valueReferenceQueue.poll()) != null) { |
| @SuppressWarnings("unchecked") |
| WeakValueReference<K, V, E> valueReference = (WeakValueReference<K, V, E>) ref; |
| map.reclaimValue(valueReference); |
| if (++i == DRAIN_MAX) { |
| break; |
| } |
| } |
| } |
| |
| <T> void clearReferenceQueue(ReferenceQueue<T> referenceQueue) { |
| while (referenceQueue.poll() != null) {} |
| } |
| |
| /** Returns first entry of bin for given hash. */ |
| E getFirst(int hash) { |
| // read this volatile field only once |
| AtomicReferenceArray<E> table = this.table; |
| return table.get(hash & (table.length() - 1)); |
| } |
| |
| // Specialized implementations of map methods |
| |
| E getEntry(Object key, int hash) { |
| if (count != 0) { // read-volatile |
| for (E e = getFirst(hash); e != null; e = e.getNext()) { |
| if (e.getHash() != hash) { |
| continue; |
| } |
| |
| K entryKey = e.getKey(); |
| if (entryKey == null) { |
| tryDrainReferenceQueues(); |
| continue; |
| } |
| |
| if (map.keyEquivalence.equivalent(key, entryKey)) { |
| return e; |
| } |
| } |
| } |
| |
| return null; |
| } |
| |
| E getLiveEntry(Object key, int hash) { |
| return getEntry(key, hash); |
| } |
| |
| V get(Object key, int hash) { |
| try { |
| E e = getLiveEntry(key, hash); |
| if (e == null) { |
| return null; |
| } |
| |
| V value = e.getValue(); |
| if (value == null) { |
| tryDrainReferenceQueues(); |
| } |
| return value; |
| } finally { |
| postReadCleanup(); |
| } |
| } |
| |
| boolean containsKey(Object key, int hash) { |
| try { |
| if (count != 0) { // read-volatile |
| E e = getLiveEntry(key, hash); |
| return e != null && e.getValue() != null; |
| } |
| |
| return false; |
| } finally { |
| postReadCleanup(); |
| } |
| } |
| |
| /** |
| * This method is a convenience for testing. Code should call {@link |
| * MapMakerInternalMap#containsValue} directly. |
| */ |
| @VisibleForTesting |
| boolean containsValue(Object value) { |
| try { |
| if (count != 0) { // read-volatile |
| AtomicReferenceArray<E> table = this.table; |
| int length = table.length(); |
| for (int i = 0; i < length; ++i) { |
| for (E e = table.get(i); e != null; e = e.getNext()) { |
| V entryValue = getLiveValue(e); |
| if (entryValue == null) { |
| continue; |
| } |
| if (map.valueEquivalence().equivalent(value, entryValue)) { |
| return true; |
| } |
| } |
| } |
| } |
| |
| return false; |
| } finally { |
| postReadCleanup(); |
| } |
| } |
| |
| V put(K key, int hash, V value, boolean onlyIfAbsent) { |
| lock(); |
| try { |
| preWriteCleanup(); |
| |
| int newCount = this.count + 1; |
| if (newCount > this.threshold) { // ensure capacity |
| expand(); |
| newCount = this.count + 1; |
| } |
| |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| // Look for an existing entry. |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| // We found an existing entry. |
| |
| V entryValue = e.getValue(); |
| |
| if (entryValue == null) { |
| ++modCount; |
| setValue(e, value); |
| newCount = this.count; // count remains unchanged |
| this.count = newCount; // write-volatile |
| return null; |
| } else if (onlyIfAbsent) { |
| // Mimic |
| // "if (!map.containsKey(key)) ... |
| // else return map.get(key); |
| return entryValue; |
| } else { |
| // clobber existing entry, count remains unchanged |
| ++modCount; |
| setValue(e, value); |
| return entryValue; |
| } |
| } |
| } |
| |
| // Create a new entry. |
| ++modCount; |
| E newEntry = map.entryHelper.newEntry(self(), key, hash, first); |
| setValue(newEntry, value); |
| table.set(index, newEntry); |
| this.count = newCount; // write-volatile |
| return null; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| /** Expands the table if possible. */ |
| @GuardedBy("this") |
| void expand() { |
| AtomicReferenceArray<E> oldTable = table; |
| int oldCapacity = oldTable.length(); |
| if (oldCapacity >= MAXIMUM_CAPACITY) { |
| return; |
| } |
| |
| /* |
| * Reclassify nodes in each list to new Map. Because we are using power-of-two expansion, the |
| * elements from each bin must either stay at same index, or move with a power of two offset. |
| * We eliminate unnecessary node creation by catching cases where old nodes can be reused |
| * because their next fields won't change. Statistically, at the default threshold, only |
| * about one-sixth of them need cloning when a table doubles. The nodes they replace will be |
| * garbage collectable as soon as they are no longer referenced by any reader thread that may |
| * be in the midst of traversing table right now. |
| */ |
| |
| int newCount = count; |
| AtomicReferenceArray<E> newTable = newEntryArray(oldCapacity << 1); |
| threshold = newTable.length() * 3 / 4; |
| int newMask = newTable.length() - 1; |
| for (int oldIndex = 0; oldIndex < oldCapacity; ++oldIndex) { |
| // We need to guarantee that any existing reads of old Map can |
| // proceed. So we cannot yet null out each bin. |
| E head = oldTable.get(oldIndex); |
| |
| if (head != null) { |
| E next = head.getNext(); |
| int headIndex = head.getHash() & newMask; |
| |
| // Single node on list |
| if (next == null) { |
| newTable.set(headIndex, head); |
| } else { |
| // Reuse the consecutive sequence of nodes with the same target |
| // index from the end of the list. tail points to the first |
| // entry in the reusable list. |
| E tail = head; |
| int tailIndex = headIndex; |
| for (E e = next; e != null; e = e.getNext()) { |
| int newIndex = e.getHash() & newMask; |
| if (newIndex != tailIndex) { |
| // The index changed. We'll need to copy the previous entry. |
| tailIndex = newIndex; |
| tail = e; |
| } |
| } |
| newTable.set(tailIndex, tail); |
| |
| // Clone nodes leading up to the tail. |
| for (E e = head; e != tail; e = e.getNext()) { |
| int newIndex = e.getHash() & newMask; |
| E newNext = newTable.get(newIndex); |
| E newFirst = copyEntry(e, newNext); |
| if (newFirst != null) { |
| newTable.set(newIndex, newFirst); |
| } else { |
| newCount--; |
| } |
| } |
| } |
| } |
| } |
| table = newTable; |
| this.count = newCount; |
| } |
| |
| boolean replace(K key, int hash, V oldValue, V newValue) { |
| lock(); |
| try { |
| preWriteCleanup(); |
| |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| // If the value disappeared, this entry is partially collected, |
| // and we should pretend like it doesn't exist. |
| V entryValue = e.getValue(); |
| if (entryValue == null) { |
| if (isCollected(e)) { |
| int newCount = this.count - 1; |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| } |
| return false; |
| } |
| |
| if (map.valueEquivalence().equivalent(oldValue, entryValue)) { |
| ++modCount; |
| setValue(e, newValue); |
| return true; |
| } else { |
| // Mimic |
| // "if (map.containsKey(key) && map.get(key).equals(oldValue))..." |
| return false; |
| } |
| } |
| } |
| |
| return false; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| V replace(K key, int hash, V newValue) { |
| lock(); |
| try { |
| preWriteCleanup(); |
| |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| // If the value disappeared, this entry is partially collected, |
| // and we should pretend like it doesn't exist. |
| V entryValue = e.getValue(); |
| if (entryValue == null) { |
| if (isCollected(e)) { |
| int newCount = this.count - 1; |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| } |
| return null; |
| } |
| |
| ++modCount; |
| setValue(e, newValue); |
| return entryValue; |
| } |
| } |
| |
| return null; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| @CanIgnoreReturnValue |
| V remove(Object key, int hash) { |
| lock(); |
| try { |
| preWriteCleanup(); |
| |
| int newCount = this.count - 1; |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| V entryValue = e.getValue(); |
| |
| if (entryValue != null) { |
| // TODO(kak): Remove this branch |
| } else if (isCollected(e)) { |
| // TODO(kak): Remove this branch |
| } else { |
| return null; |
| } |
| |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| return entryValue; |
| } |
| } |
| |
| return null; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| boolean remove(Object key, int hash, Object value) { |
| lock(); |
| try { |
| preWriteCleanup(); |
| |
| int newCount = this.count - 1; |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| V entryValue = e.getValue(); |
| |
| boolean explicitRemoval = false; |
| if (map.valueEquivalence().equivalent(value, entryValue)) { |
| explicitRemoval = true; |
| } else if (isCollected(e)) { |
| // TODO(kak): Remove this branch |
| } else { |
| return false; |
| } |
| |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| return explicitRemoval; |
| } |
| } |
| |
| return false; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| void clear() { |
| if (count != 0) { |
| lock(); |
| try { |
| AtomicReferenceArray<E> table = this.table; |
| for (int i = 0; i < table.length(); ++i) { |
| table.set(i, null); |
| } |
| maybeClearReferenceQueues(); |
| readCount.set(0); |
| |
| ++modCount; |
| count = 0; // write-volatile |
| } finally { |
| unlock(); |
| } |
| } |
| } |
| |
| /** |
| * Removes an entry from within a table. All entries following the removed node can stay, but |
| * all preceding ones need to be cloned. |
| * |
| * <p>This method does not decrement count for the removed entry, but does decrement count for |
| * all partially collected entries which are skipped. As such callers which are modifying count |
| * must re-read it after calling removeFromChain. |
| * |
| * @param first the first entry of the table |
| * @param entry the entry being removed from the table |
| * @return the new first entry for the table |
| */ |
| @GuardedBy("this") |
| E removeFromChain(E first, E entry) { |
| int newCount = count; |
| E newFirst = entry.getNext(); |
| for (E e = first; e != entry; e = e.getNext()) { |
| E next = copyEntry(e, newFirst); |
| if (next != null) { |
| newFirst = next; |
| } else { |
| newCount--; |
| } |
| } |
| this.count = newCount; |
| return newFirst; |
| } |
| |
| /** Removes an entry whose key has been garbage collected. */ |
| @CanIgnoreReturnValue |
| boolean reclaimKey(E entry, int hash) { |
| lock(); |
| try { |
| int newCount = count - 1; |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| if (e == entry) { |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| return true; |
| } |
| } |
| |
| return false; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| /** Removes an entry whose value has been garbage collected. */ |
| @CanIgnoreReturnValue |
| boolean reclaimValue(K key, int hash, WeakValueReference<K, V, E> valueReference) { |
| lock(); |
| try { |
| int newCount = this.count - 1; |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| WeakValueReference<K, V, E> v = ((WeakValueEntry<K, V, E>) e).getValueReference(); |
| if (v == valueReference) { |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| return true; |
| } |
| return false; |
| } |
| } |
| |
| return false; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| /** Clears a value that has not yet been set, and thus does not require count to be modified. */ |
| @CanIgnoreReturnValue |
| boolean clearValueForTesting( |
| K key, |
| int hash, |
| WeakValueReference<K, V, ? extends InternalEntry<K, V, ?>> valueReference) { |
| lock(); |
| try { |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| K entryKey = e.getKey(); |
| if (e.getHash() == hash |
| && entryKey != null |
| && map.keyEquivalence.equivalent(key, entryKey)) { |
| WeakValueReference<K, V, E> v = ((WeakValueEntry<K, V, E>) e).getValueReference(); |
| if (v == valueReference) { |
| E newFirst = removeFromChain(first, e); |
| table.set(index, newFirst); |
| return true; |
| } |
| return false; |
| } |
| } |
| |
| return false; |
| } finally { |
| unlock(); |
| } |
| } |
| |
| @GuardedBy("this") |
| boolean removeEntryForTesting(E entry) { |
| int hash = entry.getHash(); |
| int newCount = this.count - 1; |
| AtomicReferenceArray<E> table = this.table; |
| int index = hash & (table.length() - 1); |
| E first = table.get(index); |
| |
| for (E e = first; e != null; e = e.getNext()) { |
| if (e == entry) { |
| ++modCount; |
| E newFirst = removeFromChain(first, e); |
| newCount = this.count - 1; |
| table.set(index, newFirst); |
| this.count = newCount; // write-volatile |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Returns {@code true} if the value has been partially collected, meaning that the value is |
| * null. |
| */ |
| static <K, V, E extends InternalEntry<K, V, E>> boolean isCollected(E entry) { |
| return entry.getValue() == null; |
| } |
| |
| /** |
| * Gets the value from an entry. Returns {@code null} if the entry is invalid or |
| * partially-collected. |
| */ |
| @NullableDecl |
| V getLiveValue(E entry) { |
| if (entry.getKey() == null) { |
| tryDrainReferenceQueues(); |
| return null; |
| } |
| V value = entry.getValue(); |
| if (value == null) { |
| tryDrainReferenceQueues(); |
| return null; |
| } |
| |
| return value; |
| } |
| |
| /** |
| * Performs routine cleanup following a read. Normally cleanup happens during writes, or from |
| * the cleanupExecutor. If cleanup is not observed after a sufficient number of reads, try |
| * cleaning up from the read thread. |
| */ |
| void postReadCleanup() { |
| if ((readCount.incrementAndGet() & DRAIN_THRESHOLD) == 0) { |
| runCleanup(); |
| } |
| } |
| |
| /** |
| * Performs routine cleanup prior to executing a write. This should be called every time a write |
| * thread acquires the segment lock, immediately after acquiring the lock. |
| */ |
| @GuardedBy("this") |
| void preWriteCleanup() { |
| runLockedCleanup(); |
| } |
| |
| void runCleanup() { |
| runLockedCleanup(); |
| } |
| |
| void runLockedCleanup() { |
| if (tryLock()) { |
| try { |
| maybeDrainReferenceQueues(); |
| readCount.set(0); |
| } finally { |
| unlock(); |
| } |
| } |
| } |
| } |
| |
| /** Concrete implementation of {@link Segment} for strong keys and strong values. */ |
| static final class StrongKeyStrongValueSegment<K, V> |
| extends Segment<K, V, StrongKeyStrongValueEntry<K, V>, StrongKeyStrongValueSegment<K, V>> { |
| StrongKeyStrongValueSegment( |
| MapMakerInternalMap< |
| K, V, StrongKeyStrongValueEntry<K, V>, StrongKeyStrongValueSegment<K, V>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| super(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| StrongKeyStrongValueSegment<K, V> self() { |
| return this; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public StrongKeyStrongValueEntry<K, V> castForTesting(InternalEntry<K, V, ?> entry) { |
| return (StrongKeyStrongValueEntry<K, V>) entry; |
| } |
| } |
| |
| /** Concrete implementation of {@link Segment} for strong keys and weak values. */ |
| static final class StrongKeyWeakValueSegment<K, V> |
| extends Segment<K, V, StrongKeyWeakValueEntry<K, V>, StrongKeyWeakValueSegment<K, V>> { |
| private final ReferenceQueue<V> queueForValues = new ReferenceQueue<V>(); |
| |
| StrongKeyWeakValueSegment( |
| MapMakerInternalMap<K, V, StrongKeyWeakValueEntry<K, V>, StrongKeyWeakValueSegment<K, V>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| super(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| StrongKeyWeakValueSegment<K, V> self() { |
| return this; |
| } |
| |
| @Override |
| ReferenceQueue<V> getValueReferenceQueueForTesting() { |
| return queueForValues; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public StrongKeyWeakValueEntry<K, V> castForTesting(InternalEntry<K, V, ?> entry) { |
| return (StrongKeyWeakValueEntry<K, V>) entry; |
| } |
| |
| @Override |
| public WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> getWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> e) { |
| return castForTesting(e).getValueReference(); |
| } |
| |
| @Override |
| public WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> newWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> e, V value) { |
| return new WeakValueReferenceImpl<>(queueForValues, value, castForTesting(e)); |
| } |
| |
| @Override |
| public void setWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> e, |
| WeakValueReference<K, V, ? extends InternalEntry<K, V, ?>> valueReference) { |
| StrongKeyWeakValueEntry<K, V> entry = castForTesting(e); |
| @SuppressWarnings("unchecked") |
| WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> newValueReference = |
| (WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>>) valueReference; |
| WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> previous = entry.valueReference; |
| entry.valueReference = newValueReference; |
| previous.clear(); |
| } |
| |
| @Override |
| void maybeDrainReferenceQueues() { |
| drainValueReferenceQueue(queueForValues); |
| } |
| |
| @Override |
| void maybeClearReferenceQueues() { |
| clearReferenceQueue(queueForValues); |
| } |
| } |
| |
| /** Concrete implementation of {@link Segment} for strong keys and {@link Dummy} values. */ |
| static final class StrongKeyDummyValueSegment<K> |
| extends Segment<K, Dummy, StrongKeyDummyValueEntry<K>, StrongKeyDummyValueSegment<K>> { |
| StrongKeyDummyValueSegment( |
| MapMakerInternalMap<K, Dummy, StrongKeyDummyValueEntry<K>, StrongKeyDummyValueSegment<K>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| super(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| StrongKeyDummyValueSegment<K> self() { |
| return this; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public StrongKeyDummyValueEntry<K> castForTesting(InternalEntry<K, Dummy, ?> entry) { |
| return (StrongKeyDummyValueEntry<K>) entry; |
| } |
| } |
| |
| /** Concrete implementation of {@link Segment} for weak keys and strong values. */ |
| static final class WeakKeyStrongValueSegment<K, V> |
| extends Segment<K, V, WeakKeyStrongValueEntry<K, V>, WeakKeyStrongValueSegment<K, V>> { |
| private final ReferenceQueue<K> queueForKeys = new ReferenceQueue<K>(); |
| |
| WeakKeyStrongValueSegment( |
| MapMakerInternalMap<K, V, WeakKeyStrongValueEntry<K, V>, WeakKeyStrongValueSegment<K, V>> |
| map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| super(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| WeakKeyStrongValueSegment<K, V> self() { |
| return this; |
| } |
| |
| @Override |
| ReferenceQueue<K> getKeyReferenceQueueForTesting() { |
| return queueForKeys; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public WeakKeyStrongValueEntry<K, V> castForTesting(InternalEntry<K, V, ?> entry) { |
| return (WeakKeyStrongValueEntry<K, V>) entry; |
| } |
| |
| @Override |
| void maybeDrainReferenceQueues() { |
| drainKeyReferenceQueue(queueForKeys); |
| } |
| |
| @Override |
| void maybeClearReferenceQueues() { |
| clearReferenceQueue(queueForKeys); |
| } |
| } |
| |
| /** Concrete implementation of {@link Segment} for weak keys and weak values. */ |
| static final class WeakKeyWeakValueSegment<K, V> |
| extends Segment<K, V, WeakKeyWeakValueEntry<K, V>, WeakKeyWeakValueSegment<K, V>> { |
| private final ReferenceQueue<K> queueForKeys = new ReferenceQueue<K>(); |
| private final ReferenceQueue<V> queueForValues = new ReferenceQueue<V>(); |
| |
| WeakKeyWeakValueSegment( |
| MapMakerInternalMap<K, V, WeakKeyWeakValueEntry<K, V>, WeakKeyWeakValueSegment<K, V>> map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| super(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| WeakKeyWeakValueSegment<K, V> self() { |
| return this; |
| } |
| |
| @Override |
| ReferenceQueue<K> getKeyReferenceQueueForTesting() { |
| return queueForKeys; |
| } |
| |
| @Override |
| ReferenceQueue<V> getValueReferenceQueueForTesting() { |
| return queueForValues; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public WeakKeyWeakValueEntry<K, V> castForTesting(InternalEntry<K, V, ?> entry) { |
| return (WeakKeyWeakValueEntry<K, V>) entry; |
| } |
| |
| @Override |
| public WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> getWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> e) { |
| return castForTesting(e).getValueReference(); |
| } |
| |
| @Override |
| public WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> newWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> e, V value) { |
| return new WeakValueReferenceImpl<>(queueForValues, value, castForTesting(e)); |
| } |
| |
| @Override |
| public void setWeakValueReferenceForTesting( |
| InternalEntry<K, V, ?> e, |
| WeakValueReference<K, V, ? extends InternalEntry<K, V, ?>> valueReference) { |
| WeakKeyWeakValueEntry<K, V> entry = castForTesting(e); |
| @SuppressWarnings("unchecked") |
| WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> newValueReference = |
| (WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>>) valueReference; |
| WeakValueReference<K, V, WeakKeyWeakValueEntry<K, V>> previous = entry.valueReference; |
| entry.valueReference = newValueReference; |
| previous.clear(); |
| } |
| |
| @Override |
| void maybeDrainReferenceQueues() { |
| drainKeyReferenceQueue(queueForKeys); |
| drainValueReferenceQueue(queueForValues); |
| } |
| |
| @Override |
| void maybeClearReferenceQueues() { |
| clearReferenceQueue(queueForKeys); |
| } |
| } |
| |
| /** Concrete implementation of {@link Segment} for weak keys and {@link Dummy} values. */ |
| static final class WeakKeyDummyValueSegment<K> |
| extends Segment<K, Dummy, WeakKeyDummyValueEntry<K>, WeakKeyDummyValueSegment<K>> { |
| private final ReferenceQueue<K> queueForKeys = new ReferenceQueue<K>(); |
| |
| WeakKeyDummyValueSegment( |
| MapMakerInternalMap<K, Dummy, WeakKeyDummyValueEntry<K>, WeakKeyDummyValueSegment<K>> map, |
| int initialCapacity, |
| int maxSegmentSize) { |
| super(map, initialCapacity, maxSegmentSize); |
| } |
| |
| @Override |
| WeakKeyDummyValueSegment<K> self() { |
| return this; |
| } |
| |
| @Override |
| ReferenceQueue<K> getKeyReferenceQueueForTesting() { |
| return queueForKeys; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public WeakKeyDummyValueEntry<K> castForTesting(InternalEntry<K, Dummy, ?> entry) { |
| return (WeakKeyDummyValueEntry<K>) entry; |
| } |
| |
| @Override |
| void maybeDrainReferenceQueues() { |
| drainKeyReferenceQueue(queueForKeys); |
| } |
| |
| @Override |
| void maybeClearReferenceQueues() { |
| clearReferenceQueue(queueForKeys); |
| } |
| } |
| |
| static final class CleanupMapTask implements Runnable { |
| final WeakReference<MapMakerInternalMap<?, ?, ?, ?>> mapReference; |
| |
| public CleanupMapTask(MapMakerInternalMap<?, ?, ?, ?> map) { |
| this.mapReference = new WeakReference<MapMakerInternalMap<?, ?, ?, ?>>(map); |
| } |
| |
| @Override |
| public void run() { |
| MapMakerInternalMap<?, ?, ?, ?> map = mapReference.get(); |
| if (map == null) { |
| throw new CancellationException(); |
| } |
| |
| for (Segment<?, ?, ?, ?> segment : map.segments) { |
| segment.runCleanup(); |
| } |
| } |
| } |
| |
| @VisibleForTesting |
| Strength keyStrength() { |
| return entryHelper.keyStrength(); |
| } |
| |
| @VisibleForTesting |
| Strength valueStrength() { |
| return entryHelper.valueStrength(); |
| } |
| |
| @VisibleForTesting |
| Equivalence<Object> valueEquivalence() { |
| return entryHelper.valueStrength().defaultEquivalence(); |
| } |
| |
| // ConcurrentMap methods |
| |
| @Override |
| public boolean isEmpty() { |
| /* |
| * Sum per-segment modCounts to avoid mis-reporting when elements are concurrently added and |
| * removed in one segment while checking another, in which case the table was never actually |
| * empty at any point. (The sum ensures accuracy up through at least 1<<31 per-segment |
| * modifications before recheck.) Method containsValue() uses similar constructions for |
| * stability checks. |
| */ |
| long sum = 0L; |
| Segment<K, V, E, S>[] segments = this.segments; |
| for (int i = 0; i < segments.length; ++i) { |
| if (segments[i].count != 0) { |
| return false; |
| } |
| sum += segments[i].modCount; |
| } |
| |
| if (sum != 0L) { // recheck unless no modifications |
| for (int i = 0; i < segments.length; ++i) { |
| if (segments[i].count != 0) { |
| return false; |
| } |
| sum -= segments[i].modCount; |
| } |
| if (sum != 0L) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| @Override |
| public int size() { |
| Segment<K, V, E, S>[] segments = this.segments; |
| long sum = 0; |
| for (int i = 0; i < segments.length; ++i) { |
| sum += segments[i].count; |
| } |
| return Ints.saturatedCast(sum); |
| } |
| |
| @Override |
| public V get(@NullableDecl Object key) { |
| if (key == null) { |
| return null; |
| } |
| int hash = hash(key); |
| return segmentFor(hash).get(key, hash); |
| } |
| |
| /** |
| * Returns the internal entry for the specified key. The entry may be computing or partially |
| * collected. Does not impact recency ordering. |
| */ |
| E getEntry(@NullableDecl Object key) { |
| if (key == null) { |
| return null; |
| } |
| int hash = hash(key); |
| return segmentFor(hash).getEntry(key, hash); |
| } |
| |
| @Override |
| public boolean containsKey(@NullableDecl Object key) { |
| if (key == null) { |
| return false; |
| } |
| int hash = hash(key); |
| return segmentFor(hash).containsKey(key, hash); |
| } |
| |
| @Override |
| public boolean containsValue(@NullableDecl Object value) { |
| if (value == null) { |
| return false; |
| } |
| |
| // This implementation is patterned after ConcurrentHashMap, but without the locking. The only |
| // way for it to return a false negative would be for the target value to jump around in the map |
| // such that none of the subsequent iterations observed it, despite the fact that at every point |
| // in time it was present somewhere int the map. This becomes increasingly unlikely as |
| // CONTAINS_VALUE_RETRIES increases, though without locking it is theoretically possible. |
| final Segment<K, V, E, S>[] segments = this.segments; |
| long last = -1L; |
| for (int i = 0; i < CONTAINS_VALUE_RETRIES; i++) { |
| long sum = 0L; |
| for (Segment<K, V, E, S> segment : segments) { |
| // ensure visibility of most recent completed write |
| int unused = segment.count; // read-volatile |
| |
| AtomicReferenceArray<E> table = segment.table; |
| for (int j = 0; j < table.length(); j++) { |
| for (E e = table.get(j); e != null; e = e.getNext()) { |
| V v = segment.getLiveValue(e); |
| if (v != null && valueEquivalence().equivalent(value, v)) { |
| return true; |
| } |
| } |
| } |
| sum += segment.modCount; |
| } |
| if (sum == last) { |
| break; |
| } |
| last = sum; |
| } |
| return false; |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public V put(K key, V value) { |
| checkNotNull(key); |
| checkNotNull(value); |
| int hash = hash(key); |
| return segmentFor(hash).put(key, hash, value, false); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public V putIfAbsent(K key, V value) { |
| checkNotNull(key); |
| checkNotNull(value); |
| int hash = hash(key); |
| return segmentFor(hash).put(key, hash, value, true); |
| } |
| |
| @Override |
| public void putAll(Map<? extends K, ? extends V> m) { |
| for (Entry<? extends K, ? extends V> e : m.entrySet()) { |
| put(e.getKey(), e.getValue()); |
| } |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public V remove(@NullableDecl Object key) { |
| if (key == null) { |
| return null; |
| } |
| int hash = hash(key); |
| return segmentFor(hash).remove(key, hash); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public boolean remove(@NullableDecl Object key, @NullableDecl Object value) { |
| if (key == null || value == null) { |
| return false; |
| } |
| int hash = hash(key); |
| return segmentFor(hash).remove(key, hash, value); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public boolean replace(K key, @NullableDecl V oldValue, V newValue) { |
| checkNotNull(key); |
| checkNotNull(newValue); |
| if (oldValue == null) { |
| return false; |
| } |
| int hash = hash(key); |
| return segmentFor(hash).replace(key, hash, oldValue, newValue); |
| } |
| |
| @CanIgnoreReturnValue |
| @Override |
| public V replace(K key, V value) { |
| checkNotNull(key); |
| checkNotNull(value); |
| int hash = hash(key); |
| return segmentFor(hash).replace(key, hash, value); |
| } |
| |
| @Override |
| public void clear() { |
| for (Segment<K, V, E, S> segment : segments) { |
| segment.clear(); |
| } |
| } |
| |
| @MonotonicNonNullDecl transient Set<K> keySet; |
| |
| @Override |
| public Set<K> keySet() { |
| Set<K> ks = keySet; |
| return (ks != null) ? ks : (keySet = new KeySet()); |
| } |
| |
| @MonotonicNonNullDecl transient Collection<V> values; |
| |
| @Override |
| public Collection<V> values() { |
| Collection<V> vs = values; |
| return (vs != null) ? vs : (values = new Values()); |
| } |
| |
| @MonotonicNonNullDecl transient Set<Entry<K, V>> entrySet; |
| |
| @Override |
| public Set<Entry<K, V>> entrySet() { |
| Set<Entry<K, V>> es = entrySet; |
| return (es != null) ? es : (entrySet = new EntrySet()); |
| } |
| |
| // Iterator Support |
| |
| abstract class HashIterator<T> implements Iterator<T> { |
| |
| int nextSegmentIndex; |
| int nextTableIndex; |
| @MonotonicNonNullDecl Segment<K, V, E, S> currentSegment; |
| @MonotonicNonNullDecl AtomicReferenceArray<E> currentTable; |
| @NullableDecl E nextEntry; |
| @NullableDecl WriteThroughEntry nextExternal; |
| @NullableDecl WriteThroughEntry lastReturned; |
| |
| HashIterator() { |
| nextSegmentIndex = segments.length - 1; |
| nextTableIndex = -1; |
| advance(); |
| } |
| |
| @Override |
| public abstract T next(); |
| |
| final void advance() { |
| nextExternal = null; |
| |
| if (nextInChain()) { |
| return; |
| } |
| |
| if (nextInTable()) { |
| return; |
| } |
| |
| while (nextSegmentIndex >= 0) { |
| currentSegment = segments[nextSegmentIndex--]; |
| if (currentSegment.count != 0) { |
| currentTable = currentSegment.table; |
| nextTableIndex = currentTable.length() - 1; |
| if (nextInTable()) { |
| return; |
| } |
| } |
| } |
| } |
| |
| /** Finds the next entry in the current chain. Returns {@code true} if an entry was found. */ |
| boolean nextInChain() { |
| if (nextEntry != null) { |
| for (nextEntry = nextEntry.getNext(); nextEntry != null; nextEntry = nextEntry.getNext()) { |
| if (advanceTo(nextEntry)) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| /** Finds the next entry in the current table. Returns {@code true} if an entry was found. */ |
| boolean nextInTable() { |
| while (nextTableIndex >= 0) { |
| if ((nextEntry = currentTable.get(nextTableIndex--)) != null) { |
| if (advanceTo(nextEntry) || nextInChain()) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Advances to the given entry. Returns {@code true} if the entry was valid, {@code false} if it |
| * should be skipped. |
| */ |
| boolean advanceTo(E entry) { |
| try { |
| K key = entry.getKey(); |
| V value = getLiveValue(entry); |
| if (value != null) { |
| nextExternal = new WriteThroughEntry(key, value); |
| return true; |
| } else { |
| // Skip stale entry. |
| return false; |
| } |
| } finally { |
| currentSegment.postReadCleanup(); |
| } |
| } |
| |
| @Override |
| public boolean hasNext() { |
| return nextExternal != null; |
| } |
| |
| WriteThroughEntry nextEntry() { |
| if (nextExternal == null) { |
| throw new NoSuchElementException(); |
| } |
| lastReturned = nextExternal; |
| advance(); |
| return lastReturned; |
| } |
| |
| @Override |
| public void remove() { |
| checkRemove(lastReturned != null); |
| MapMakerInternalMap.this.remove(lastReturned.getKey()); |
| lastReturned = null; |
| } |
| } |
| |
| final class KeyIterator extends HashIterator<K> { |
| |
| @Override |
| public K next() { |
| return nextEntry().getKey(); |
| } |
| } |
| |
| final class ValueIterator extends HashIterator<V> { |
| |
| @Override |
| public V next() { |
| return nextEntry().getValue(); |
| } |
| } |
| |
| /** |
| * Custom Entry class used by EntryIterator.next(), that relays setValue changes to the underlying |
| * map. |
| */ |
| final class WriteThroughEntry extends AbstractMapEntry<K, V> { |
| final K key; // non-null |
| V value; // non-null |
| |
| WriteThroughEntry(K key, V value) { |
| this.key = key; |
| this.value = value; |
| } |
| |
| @Override |
| public K getKey() { |
| return key; |
| } |
| |
| @Override |
| public V getValue() { |
| return value; |
| } |
| |
| @Override |
| public boolean equals(@NullableDecl Object object) { |
| // Cannot use key and value equivalence |
| if (object instanceof Entry) { |
| Entry<?, ?> that = (Entry<?, ?>) object; |
| return key.equals(that.getKey()) && value.equals(that.getValue()); |
| } |
| return false; |
| } |
| |
| @Override |
| public int hashCode() { |
| // Cannot use key and value equivalence |
| return key.hashCode() ^ value.hashCode(); |
| } |
| |
| @Override |
| public V setValue(V newValue) { |
| V oldValue = put(key, newValue); |
| value = newValue; // only if put succeeds |
| return oldValue; |
| } |
| } |
| |
| final class EntryIterator extends HashIterator<Entry<K, V>> { |
| |
| @Override |
| public Entry<K, V> next() { |
| return nextEntry(); |
| } |
| } |
| |
| @WeakOuter |
| final class KeySet extends SafeToArraySet<K> { |
| |
| @Override |
| public Iterator<K> iterator() { |
| return new KeyIterator(); |
| } |
| |
| @Override |
| public int size() { |
| return MapMakerInternalMap.this.size(); |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return MapMakerInternalMap.this.isEmpty(); |
| } |
| |
| @Override |
| public boolean contains(Object o) { |
| return MapMakerInternalMap.this.containsKey(o); |
| } |
| |
| @Override |
| public boolean remove(Object o) { |
| return MapMakerInternalMap.this.remove(o) != null; |
| } |
| |
| @Override |
| public void clear() { |
| MapMakerInternalMap.this.clear(); |
| } |
| } |
| |
| @WeakOuter |
| final class Values extends AbstractCollection<V> { |
| |
| @Override |
| public Iterator<V> iterator() { |
| return new ValueIterator(); |
| } |
| |
| @Override |
| public int size() { |
| return MapMakerInternalMap.this.size(); |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return MapMakerInternalMap.this.isEmpty(); |
| } |
| |
| @Override |
| public boolean contains(Object o) { |
| return MapMakerInternalMap.this.containsValue(o); |
| } |
| |
| @Override |
| public void clear() { |
| MapMakerInternalMap.this.clear(); |
| } |
| |
| // super.toArray() may misbehave if size() is inaccurate, at least on old versions of Android. |
| // https://code.google.com/p/android/issues/detail?id=36519 / http://r.android.com/47508 |
| |
| @Override |
| public Object[] toArray() { |
| return toArrayList(this).toArray(); |
| } |
| |
| @Override |
| public <T> T[] toArray(T[] a) { |
| return toArrayList(this).toArray(a); |
| } |
| } |
| |
| @WeakOuter |
| final class EntrySet extends SafeToArraySet<Entry<K, V>> { |
| |
| @Override |
| public Iterator<Entry<K, V>> iterator() { |
| return new EntryIterator(); |
| } |
| |
| @Override |
| public boolean contains(Object o) { |
| if (!(o instanceof Entry)) { |
| return false; |
| } |
| Entry<?, ?> e = (Entry<?, ?>) o; |
| Object key = e.getKey(); |
| if (key == null) { |
| return false; |
| } |
| V v = MapMakerInternalMap.this.get(key); |
| |
| return v != null && valueEquivalence().equivalent(e.getValue(), v); |
| } |
| |
| @Override |
| public boolean remove(Object o) { |
| if (!(o instanceof Entry)) { |
| return false; |
| } |
| Entry<?, ?> e = (Entry<?, ?>) o; |
| Object key = e.getKey(); |
| return key != null && MapMakerInternalMap.this.remove(key, e.getValue()); |
| } |
| |
| @Override |
| public int size() { |
| return MapMakerInternalMap.this.size(); |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return MapMakerInternalMap.this.isEmpty(); |
| } |
| |
| @Override |
| public void clear() { |
| MapMakerInternalMap.this.clear(); |
| } |
| } |
| |
| private abstract static class SafeToArraySet<E> extends AbstractSet<E> { |
| // super.toArray() may misbehave if size() is inaccurate, at least on old versions of Android. |
| // https://code.google.com/p/android/issues/detail?id=36519 / http://r.android.com/47508 |
| |
| @Override |
| public Object[] toArray() { |
| return toArrayList(this).toArray(); |
| } |
| |
| @Override |
| public <T> T[] toArray(T[] a) { |
| return toArrayList(this).toArray(a); |
| } |
| } |
| |
| private static <E> ArrayList<E> toArrayList(Collection<E> c) { |
| // Avoid calling ArrayList(Collection), which may call back into toArray. |
| ArrayList<E> result = new ArrayList<>(c.size()); |
| Iterators.addAll(result, c.iterator()); |
| return result; |
| } |
| |
| // Serialization Support |
| |
| private static final long serialVersionUID = 5; |
| |
| Object writeReplace() { |
| return new SerializationProxy<>( |
| entryHelper.keyStrength(), |
| entryHelper.valueStrength(), |
| keyEquivalence, |
| entryHelper.valueStrength().defaultEquivalence(), |
| concurrencyLevel, |
| this); |
| } |
| |
| /** |
| * The actual object that gets serialized. Unfortunately, readResolve() doesn't get called when a |
| * circular dependency is present, so the proxy must be able to behave as the map itself. |
| */ |
| abstract static class AbstractSerializationProxy<K, V> extends ForwardingConcurrentMap<K, V> |
| implements Serializable { |
| private static final long serialVersionUID = 3; |
| |
| final Strength keyStrength; |
| final Strength valueStrength; |
| final Equivalence<Object> keyEquivalence; |
| final Equivalence<Object> valueEquivalence; |
| final int concurrencyLevel; |
| |
| transient ConcurrentMap<K, V> delegate; |
| |
| AbstractSerializationProxy( |
| Strength keyStrength, |
| Strength valueStrength, |
| Equivalence<Object> keyEquivalence, |
| Equivalence<Object> valueEquivalence, |
| int concurrencyLevel, |
| ConcurrentMap<K, V> delegate) { |
| this.keyStrength = keyStrength; |
| this.valueStrength = valueStrength; |
| this.keyEquivalence = keyEquivalence; |
| this.valueEquivalence = valueEquivalence; |
| this.concurrencyLevel = concurrencyLevel; |
| this.delegate = delegate; |
| } |
| |
| @Override |
| protected ConcurrentMap<K, V> delegate() { |
| return delegate; |
| } |
| |
| void writeMapTo(ObjectOutputStream out) throws IOException { |
| out.writeInt(delegate.size()); |
| for (Entry<K, V> entry : delegate.entrySet()) { |
| out.writeObject(entry.getKey()); |
| out.writeObject(entry.getValue()); |
| } |
| out.writeObject(null); // terminate entries |
| } |
| |
| @SuppressWarnings("deprecation") // serialization of deprecated feature |
| MapMaker readMapMaker(ObjectInputStream in) throws IOException { |
| int size = in.readInt(); |
| return new MapMaker() |
| .initialCapacity(size) |
| .setKeyStrength(keyStrength) |
| .setValueStrength(valueStrength) |
| .keyEquivalence(keyEquivalence) |
| .concurrencyLevel(concurrencyLevel); |
| } |
| |
| @SuppressWarnings("unchecked") |
| void readEntries(ObjectInputStream in) throws IOException, ClassNotFoundException { |
| while (true) { |
| K key = (K) in.readObject(); |
| if (key == null) { |
| break; // terminator |
| } |
| V value = (V) in.readObject(); |
| delegate.put(key, value); |
| } |
| } |
| } |
| |
| /** |
| * The actual object that gets serialized. Unfortunately, readResolve() doesn't get called when a |
| * circular dependency is present, so the proxy must be able to behave as the map itself. |
| */ |
| private static final class SerializationProxy<K, V> extends AbstractSerializationProxy<K, V> { |
| private static final long serialVersionUID = 3; |
| |
| SerializationProxy( |
| Strength keyStrength, |
| Strength valueStrength, |
| Equivalence<Object> keyEquivalence, |
| Equivalence<Object> valueEquivalence, |
| int concurrencyLevel, |
| ConcurrentMap<K, V> delegate) { |
| super( |
| keyStrength, valueStrength, keyEquivalence, valueEquivalence, concurrencyLevel, delegate); |
| } |
| |
| private void writeObject(ObjectOutputStream out) throws IOException { |
| out.defaultWriteObject(); |
| writeMapTo(out); |
| } |
| |
| private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { |
| in.defaultReadObject(); |
| MapMaker mapMaker = readMapMaker(in); |
| delegate = mapMaker.makeMap(); |
| readEntries(in); |
| } |
| |
| private Object readResolve() { |
| return delegate; |
| } |
| } |
| } |