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net.sf.ehcache.store.chm.SelectableConcurrentHashMap Maven / Gradle / Ivy
Ehcache is an open source, standards-based cache used to boost performance,
offload the database and simplify scalability. Ehcache is robust, proven and full-featured and
this has made it the most widely-used Java-based cache.
/**
* Copyright Terracotta, Inc.
*
* 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 net.sf.ehcache.store.chm;
import java.util.AbstractCollection;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import net.sf.ehcache.CacheOperationOutcomes.EvictionOutcome;
import net.sf.ehcache.Element;
import net.sf.ehcache.event.RegisteredEventListeners;
import net.sf.ehcache.pool.PoolAccessor;
import org.terracotta.statistics.observer.OperationObserver;
import static net.sf.ehcache.statistics.StatisticBuilder.operation;
/**
* SelectableConcurrentHashMap subclasses a repackaged version of ConcurrentHashMap
* ito allow efficient random sampling of the map values.
*
* The random sampling technique involves randomly selecting a map Segment, and then
* selecting a number of random entry chains from that segment.
*
* @author Chris Dennis
*/
@SuppressWarnings("ForLoopReplaceableByForEach")
public class SelectableConcurrentHashMap {
/**
* The default initial capacity for this table,
* used when not otherwise specified in a constructor.
*/
static final int DEFAULT_INITIAL_CAPACITY = 16;
/**
* The default load factor for this table, used when not
* otherwise specified in a constructor.
*/
static final float DEFAULT_LOAD_FACTOR = 0.75f;
/**
* The maximum capacity, used if a higher value is implicitly
* specified by either of the constructors with arguments. MUST
* be a power of two <= 1<<30 to ensure that entries are indexable
* using ints.
*/
private static final int MAXIMUM_CAPACITY = 1 << 30;
/**
* The maximum number of segments to allow; used to bound
* constructor arguments.
*/
private static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
/**
* Number of unsynchronized retries in size and containsValue
* methods before resorting to locking. This is used to avoid
* unbounded retries if tables undergo continuous modification
* which would make it impossible to obtain an accurate result.
*/
private static final int RETRIES_BEFORE_LOCK = 2;
/**
* Mask value for indexing into segments. The upper bits of a
* key's hash code are used to choose the segment.
*/
private final int segmentMask;
/**
* Shift value for indexing within segments.
*/
private final int segmentShift;
/**
* The segments, each of which is a specialized hash table
*/
private final Segment[] segments;
private final Random rndm = new Random();
private final PoolAccessor poolAccessor;
private volatile long maxSize;
private final RegisteredEventListeners cacheEventNotificationService;
private Set keySet;
private Set> entrySet;
private Collection values;
private final OperationObserver evictionObserver = operation(EvictionOutcome.class).named("eviction").of(this).build();
public SelectableConcurrentHashMap(PoolAccessor poolAccessor, int concurrency, final long maximumSize, final RegisteredEventListeners cacheEventNotificationService) {
this(poolAccessor, DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, concurrency, maximumSize, cacheEventNotificationService);
}
public SelectableConcurrentHashMap(PoolAccessor poolAccessor, int initialCapacity, float loadFactor, int concurrency, final long maximumSize, final RegisteredEventListeners cacheEventNotificationService) {
if (!(loadFactor > 0) || initialCapacity < 0 || concurrency <= 0)
throw new IllegalArgumentException();
if (concurrency > MAX_SEGMENTS)
concurrency = MAX_SEGMENTS;
// Find power-of-two sizes best matching arguments
int sshift = 0;
int ssize = 1;
while (ssize < concurrency) {
++sshift;
ssize <<= 1;
}
segmentShift = 32 - sshift;
segmentMask = ssize - 1;
this.segments = new Segment[ssize];
if (initialCapacity > MAXIMUM_CAPACITY)
initialCapacity = MAXIMUM_CAPACITY;
int c = initialCapacity / ssize;
if (c * ssize < initialCapacity)
++c;
int cap = 1;
while (cap < c)
cap <<= 1;
for (int i = 0; i < this.segments.length; ++i)
this.segments[i] = createSegment(cap, loadFactor);
this.poolAccessor = poolAccessor;
this.maxSize = maximumSize;
this.cacheEventNotificationService = cacheEventNotificationService;
}
public void setMaxSize(final long maxSize) {
this.maxSize = maxSize;
}
public Element[] getRandomValues(final int size, Object keyHint) {
ArrayList sampled = new ArrayList(size * 2);
// pick a random starting point in the map
int randomHash = rndm.nextInt();
final int segmentStart;
if (keyHint == null) {
segmentStart = (randomHash >>> segmentShift) & segmentMask;
} else {
segmentStart = (hash(keyHint.hashCode()) >>> segmentShift) & segmentMask;
}
int segmentIndex = segmentStart;
do {
final HashEntry[] table = segments[segmentIndex].table;
final int tableStart = randomHash & (table.length - 1);
int tableIndex = tableStart;
do {
for (HashEntry e = table[tableIndex]; e != null; e = e.next) {
Element value = e.value;
if (value != null) {
sampled.add(value);
}
}
if (sampled.size() >= size) {
return sampled.toArray(new Element[sampled.size()]);
}
//move to next table slot
tableIndex = (tableIndex + 1) & (table.length - 1);
} while (tableIndex != tableStart);
//move to next segment
segmentIndex = (segmentIndex + 1) & segmentMask;
} while (segmentIndex != segmentStart);
return sampled.toArray(new Element[sampled.size()]);
}
/**
* Return an object of the kind which will be stored when
* the element is going to be inserted
* @param e the element
* @return an object looking-alike the stored one
*/
public Object storedObject(Element e) {
return new HashEntry(null, 0, null, e, 0);
}
/**
* Returns the number of key-value mappings in this map without locking anything.
* This may not give the exact element count as locking is avoided.
* If the map contains more than Integer.MAX_VALUE elements, returns
* Integer.MAX_VALUE .
*
* @return the number of key-value mappings in this map
*/
public int quickSize() {
final Segment[] segments = this.segments;
long sum = 0;
for (Segment seg : segments) {
sum += seg.count;
}
if (sum > Integer.MAX_VALUE) {
return Integer.MAX_VALUE;
} else {
return (int)sum;
}
}
public boolean isEmpty() {
final Segment[] segments = this.segments;
/*
* We keep track of per-segment modCounts to avoid ABA
* problems in which an element in one segment was added and
* in another removed during traversal, in which case the
* table was never actually empty at any point. Note the
* similar use of modCounts in the size() and containsValue()
* methods, which are the only other methods also susceptible
* to ABA problems.
*/
int[] mc = new int[segments.length];
int mcsum = 0;
for (int i = 0; i < segments.length; ++i) {
if (segments[i].count != 0)
return false;
else
mcsum += mc[i] = segments[i].modCount;
}
// If mcsum happens to be zero, then we know we got a snapshot
// before any modifications at all were made. This is
// probably common enough to bother tracking.
if (mcsum != 0) {
for (int i = 0; i < segments.length; ++i) {
if (segments[i].count != 0 ||
mc[i] != segments[i].modCount)
return false;
}
}
return true;
}
public int size() {
final Segment[] segments = this.segments;
for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
int[] mc = new int[segments.length];
long check = 0;
long sum = 0;
int mcsum = 0;
for (int i = 0; i < segments.length; ++i) {
sum += segments[i].count;
mcsum += mc[i] = segments[i].modCount;
}
if (mcsum != 0) {
for (int i = 0; i < segments.length; ++i) {
check += segments[i].count;
if (mc[i] != segments[i].modCount) {
check = -1; // force retry
break;
}
}
}
if (check == sum) {
if (sum > Integer.MAX_VALUE) {
return Integer.MAX_VALUE;
} else {
return (int)sum;
}
}
}
long sum = 0;
for (int i = 0; i < segments.length; ++i) {
segments[i].readLock().lock();
}
try {
for (int i = 0; i < segments.length; ++i) {
sum += segments[i].count;
}
} finally {
for (int i = 0; i < segments.length; ++i) {
segments[i].readLock().unlock();
}
}
if (sum > Integer.MAX_VALUE) {
return Integer.MAX_VALUE;
} else {
return (int)sum;
}
}
public ReentrantReadWriteLock lockFor(Object key) {
int hash = hash(key.hashCode());
return segmentFor(hash);
}
public ReentrantReadWriteLock[] locks() {
return segments;
}
public Element get(Object key) {
int hash = hash(key.hashCode());
return segmentFor(hash).get(key, hash);
}
public boolean containsKey(Object key) {
int hash = hash(key.hashCode());
return segmentFor(hash).containsKey(key, hash);
}
public boolean containsValue(Object value) {
if (value == null)
throw new NullPointerException();
// See explanation of modCount use above
final Segment[] segments = this.segments;
int[] mc = new int[segments.length];
// Try a few times without locking
for (int k = 0; k < RETRIES_BEFORE_LOCK; ++k) {
int sum = 0;
int mcsum = 0;
for (int i = 0; i < segments.length; ++i) {
int c = segments[i].count;
mcsum += mc[i] = segments[i].modCount;
if (segments[i].containsValue(value))
return true;
}
boolean cleanSweep = true;
if (mcsum != 0) {
for (int i = 0; i < segments.length; ++i) {
int c = segments[i].count;
if (mc[i] != segments[i].modCount) {
cleanSweep = false;
break;
}
}
}
if (cleanSweep)
return false;
}
// Resort to locking all segments
for (int i = 0; i < segments.length; ++i)
segments[i].readLock().lock();
try {
for (int i = 0; i < segments.length; ++i) {
if (segments[i].containsValue(value)) {
return true;
}
}
} finally {
for (int i = 0; i < segments.length; ++i)
segments[i].readLock().unlock();
}
return false;
}
public Element put(Object key, Element element, long sizeOf) {
int hash = hash(key.hashCode());
return segmentFor(hash).put(key, hash, element, sizeOf, false, true);
}
public Element putIfAbsent(Object key, Element element, long sizeOf) {
int hash = hash(key.hashCode());
return segmentFor(hash).put(key, hash, element, sizeOf, true, true);
}
public Element remove(Object key) {
int hash = hash(key.hashCode());
return segmentFor(hash).remove(key, hash, null);
}
public boolean remove(Object key, Object value) {
int hash = hash(key.hashCode());
if (value == null)
return false;
return segmentFor(hash).remove(key, hash, value) != null;
}
public void clear() {
for (int i = 0; i < segments.length; ++i)
segments[i].clear();
}
public Set keySet() {
Set ks = keySet;
return (ks != null) ? ks : (keySet = new KeySet());
}
public Collection values() {
Collection vs = values;
return (vs != null) ? vs : (values = new Values());
}
public Set> entrySet() {
Set> es = entrySet;
return (es != null) ? es : (entrySet = new EntrySet());
}
protected Segment createSegment(int initialCapacity, float lf) {
return new Segment(initialCapacity, lf);
}
public boolean evict() {
return getRandomSegment().evict();
}
private Segment getRandomSegment() {
int randomHash = rndm.nextInt();
return segments[((randomHash >>> segmentShift) & segmentMask)];
}
public void recalculateSize(Object key) {
int hash = hash(key.hashCode());
segmentFor(hash).recalculateSize(key, hash);
}
/**
* Returns the segment that should be used for key with given hash
* @param hash the hash code for the key
* @return the segment
*/
protected final Segment segmentFor(int hash) {
return segments[(hash >>> segmentShift) & segmentMask];
}
protected final List segments() {
return Collections.unmodifiableList(Arrays.asList(segments));
}
public class Segment extends ReentrantReadWriteLock {
private static final int MAX_EVICTION = 5;
/**
* The number of elements in this segment's region.
*/
protected 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 rehashed when its size exceeds this threshold.
* (The value of this field is always (int)(capacity *
* loadFactor) .)
*/
int threshold;
/**
* The per-segment table.
*/
protected volatile HashEntry[] table;
/**
* The load factor for the hash table. Even though this value
* is same for all segments, it is replicated to avoid needing
* links to outer object.
* @serial
*/
final float loadFactor;
private Iterator evictionIterator;
protected Segment(int initialCapacity, float lf) {
loadFactor = lf;
setTable(new HashEntry[initialCapacity]);
}
protected void preRemove(HashEntry e) {
}
protected void postInstall(Object key, Element value) {
}
/**
* Sets table to new HashEntry array.
* Call only while holding lock or in constructor.
*/
void setTable(HashEntry[] newTable) {
threshold = (int)(newTable.length * loadFactor);
table = newTable;
}
/**
* Returns properly casted first entry of bin for given hash.
*/
protected HashEntry getFirst(int hash) {
HashEntry[] tab = table;
return tab[hash & (tab.length - 1)];
}
private HashEntry removeAndGetFirst(HashEntry e, HashEntry first) {
preRemove(e);
// All entries following removed node can stay
// in list, but all preceding ones need to be
// cloned.
HashEntry newFirst = e.next;
for (HashEntry p = first; p != e; p = p.next)
newFirst = relinkHashEntry(p, newFirst);
return newFirst;
}
protected HashEntry createHashEntry(Object key, int hash, HashEntry next, Element value, long sizeOf) {
return new HashEntry(key, hash, next, value, sizeOf);
}
protected HashEntry relinkHashEntry(HashEntry e, HashEntry next) {
return new HashEntry(e.key, e.hash, next, e.value, e.sizeOf);
}
protected void clear() {
final WriteLock writeLock = writeLock();
writeLock.lock();
try {
if (count != 0) {
HashEntry[] tab = table;
for (int i = 0; i < tab.length ; i++)
tab[i] = null;
++modCount;
count = 0; // write-volatile
}
evictionIterator = null;
} finally {
writeLock.unlock();
}
}
Element remove(Object key, int hash, Object value) {
final WriteLock writeLock = writeLock();
writeLock.lock();
try {
int c = count - 1;
HashEntry[] tab = table;
int index = hash & (tab.length - 1);
HashEntry first = tab[index];
HashEntry e = first;
while (e != null && (e.hash != hash || !key.equals(e.key)))
e = e.next;
Element oldValue = null;
if (e != null) {
Element v = e.value;
if (value == null || value.equals(v)) {
oldValue = v;
++modCount;
tab[index] = removeAndGetFirst(e, first);
count = c; // write-volatile
if (cacheEventNotificationService != null) {
cacheEventNotificationService.notifyElementRemovedOrdered(oldValue);
}
poolAccessor.delete(e.sizeOf);
if(evictionIterator != null && ((SegmentIterator)evictionIterator).nextEntry == e) {
evictionIterator.next();
}
}
}
return oldValue;
} finally {
writeLock.unlock();
}
}
public void recalculateSize(Object key, int hash) {
Element value = null;
long oldSize = 0;
final ReadLock readLock = readLock();
readLock.lock();
try {
HashEntry[] tab = table;
int index = hash & (tab.length - 1);
HashEntry first = tab[index];
HashEntry e = first;
while (e != null && (e.hash != hash || !key.equals(e.key))) {
e = e.next;
}
if (e != null) {
key = e.key;
value = e.value;
oldSize = e.sizeOf;
}
} finally {
readLock.unlock();
}
if (value != null) {
long delta = poolAccessor.replace(oldSize, key, value, storedObject(value), true);
final WriteLock writeLock = writeLock();
writeLock.lock();
try {
HashEntry e = getFirst(hash);
while (e != null && key != e.key) {
e = e.next;
}
if (e != null && e.value == value && oldSize == e.sizeOf) {
e.sizeOf = oldSize + delta;
} else {
poolAccessor.delete(delta);
}
} finally {
writeLock.unlock();
}
}
}
protected Element put(Object key, int hash, Element value, long sizeOf, boolean onlyIfAbsent, boolean fire) {
Element[] evicted = new Element[MAX_EVICTION];
final WriteLock writeLock = writeLock();
writeLock.lock();
try {
int c = count;
if (c++ > threshold) // ensure capacity
rehash();
HashEntry[] tab = table;
int index = hash & (tab.length - 1);
HashEntry first = tab[index];
HashEntry e = first;
while (e != null && (e.hash != hash || !key.equals(e.key)))
e = e.next;
Element oldValue;
if (e != null) {
oldValue = e.value;
if (!onlyIfAbsent) {
poolAccessor.delete(e.sizeOf);
e.value = value;
e.sizeOf = sizeOf;
if (cacheEventNotificationService != null) {
cacheEventNotificationService.notifyElementUpdatedOrdered(oldValue, value);
}
if (fire) {
postInstall(key, value);
}
}
} else {
oldValue = null;
++modCount;
tab[index] = createHashEntry(key, hash, first, value, sizeOf);
count = c; // write-volatile
if (cacheEventNotificationService != null) {
cacheEventNotificationService.notifyElementPutOrdered(value);
}
if (fire) {
postInstall(key, value);
}
}
if((onlyIfAbsent && oldValue != null || !onlyIfAbsent)) {
if (SelectableConcurrentHashMap.this.maxSize > 0) {
int runs = Math.min(MAX_EVICTION, SelectableConcurrentHashMap.this.quickSize() - (int) SelectableConcurrentHashMap.this.maxSize);
while (runs-- > 0) {
evictionObserver.begin();
Element evict = nextExpiredOrToEvict(value);
if (evict != null) {
Element removed;
while ((removed = remove(evict.getKey(), hash(evict.getKey().hashCode()), null)) == null) {
evict = nextExpiredOrToEvict(value);
if (evict == null) {
break;
}
}
evicted[runs] = removed;
}
evictionObserver.end(EvictionOutcome.SUCCESS);
}
}
}
return oldValue;
} finally {
writeLock.unlock();
for (Element element : evicted) {
notifyEvictionOrExpiry(element);
}
}
}
private void notifyEvictionOrExpiry(final Element element) {
if(element != null && cacheEventNotificationService != null) {
if (element.isExpired()) {
cacheEventNotificationService.notifyElementExpiry(element, false);
} else {
cacheEventNotificationService.notifyElementEvicted(element, false);
}
}
}
Element get(final Object key, final int hash) {
final ReadLock readLock = readLock();
readLock.lock();
try {
if (count != 0) { // read-volatile
HashEntry e = getFirst(hash);
while (e != null) {
if (e.hash == hash && key.equals(e.key)) {
e.accessed = true;
return e.value;
}
e = e.next;
}
}
return null;
} finally {
readLock.unlock();
}
}
boolean containsKey(final Object key, final int hash) {
final ReadLock readLock = readLock();
readLock.lock();
try {
if (count != 0) { // read-volatile
HashEntry e = getFirst(hash);
while (e != null) {
if (e.hash == hash && key.equals(e.key))
return true;
e = e.next;
}
}
return false;
} finally {
readLock.unlock();
}
}
boolean containsValue(Object value) {
final ReadLock readLock = readLock();
readLock.lock();
try {
if (count != 0) { // read-volatile
HashEntry[] tab = table;
int len = tab.length;
for (int i = 0 ; i < len; i++) {
for (HashEntry e = tab[i]; e != null; e = e.next) {
Element v = e.value;
if (value.equals(v))
return true;
}
}
}
return false;
} finally {
readLock.unlock();
}
}
private Element nextExpiredOrToEvict(final Element justAdded) {
Element lastUnpinned = null;
int i = 0;
while (i++ < count) {
if (evictionIterator == null || !evictionIterator.hasNext()) {
evictionIterator = iterator();
}
final HashEntry next = evictionIterator.next();
if (!next.accessed || next.value.isExpired()) {
return next.value;
} else {
if (next.value != justAdded) {
lastUnpinned = next.value;
}
next.accessed = false;
}
}
return lastUnpinned;
}
protected Iterator iterator() {
return new SegmentIterator(this);
}
boolean evict() {
Element remove = null;
final WriteLock writeLock = writeLock();
writeLock.lock();
try {
Element evict = nextExpiredOrToEvict(null);
if (evict != null) {
if (cacheEventNotificationService != null) {
evictionObserver.begin();
remove = remove(evict.getKey(), hash(evict.getKey().hashCode()), null);
evictionObserver.end(EvictionOutcome.SUCCESS);
} else {
remove = remove(evict.getKey(), hash(evict.getKey().hashCode()), null);
}
}
} finally {
writeLock.unlock();
}
notifyEvictionOrExpiry(remove);
return remove != null;
}
void rehash() {
HashEntry[] 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.
*/
HashEntry[] newTable = new HashEntry[oldCapacity << 1];
threshold = (int)(newTable.length * loadFactor);
int sizeMask = newTable.length - 1;
for (int i = 0; i < oldCapacity ; i++) {
// We need to guarantee that any existing reads of old Map can
// proceed. So we cannot yet null out each bin.
HashEntry e = oldTable[i];
if (e != null) {
HashEntry next = e.next;
int idx = e.hash & sizeMask;
// Single node on list
if (next == null)
newTable[idx] = e;
else {
// Reuse trailing consecutive sequence at same slot
HashEntry lastRun = e;
int lastIdx = idx;
for (HashEntry last = next;
last != null;
last = last.next) {
int k = last.hash & sizeMask;
if (k != lastIdx) {
lastIdx = k;
lastRun = last;
}
}
newTable[lastIdx] = lastRun;
// Clone all remaining nodes
for (HashEntry p = e; p != lastRun; p = p.next) {
int k = p.hash & sizeMask;
HashEntry n = newTable[k];
newTable[k] = relinkHashEntry(p, n);
}
}
}
}
table = newTable;
if (evictionIterator != null) {
evictionIterator = iterator();
}
}
Iterator getEvictionIterator() {
return evictionIterator;
}
}
public static class HashEntry {
public final Object key;
public final int hash;
public final HashEntry next;
public volatile Element value;
public volatile long sizeOf;
public volatile boolean accessed = true;
protected HashEntry(Object key, int hash, HashEntry next, Element value, long sizeOf) {
this.key = key;
this.hash = hash;
this.next = next;
this.value = value;
this.sizeOf = sizeOf;
}
}
static class SegmentIterator implements Iterator {
int nextTableIndex;
HashEntry[] currentTable;
HashEntry nextEntry;
private final Segment seg;
private SegmentIterator(final Segment memoryStoreSegment) {
nextTableIndex = -1;
this.seg = memoryStoreSegment;
advance();
}
public boolean hasNext() {
return nextEntry != null;
}
public HashEntry next() {
if (nextEntry == null)
return null;
HashEntry lastReturned = nextEntry;
advance();
return lastReturned;
}
public void remove() {
throw new UnsupportedOperationException("remove is not supported");
}
final void advance() {
if (nextEntry != null && (nextEntry = nextEntry.next) != null)
return;
while (nextTableIndex >= 0) {
if ( (nextEntry = currentTable[nextTableIndex--]) != null)
return;
}
if (seg.count != 0) {
currentTable = seg.table;
for (int j = currentTable.length - 1; j >= 0; --j) {
if ( (nextEntry = currentTable[j]) != null) {
nextTableIndex = j - 1;
return;
}
}
}
}
}
final class KeySet extends AbstractSet {
@Override
public Iterator iterator() {
return new KeyIterator();
}
@Override
public int size() {
return SelectableConcurrentHashMap.this.size();
}
@Override
public boolean isEmpty() {
return SelectableConcurrentHashMap.this.isEmpty();
}
@Override
public boolean contains(Object o) {
return SelectableConcurrentHashMap.this.containsKey(o);
}
@Override
public boolean remove(Object o) {
return SelectableConcurrentHashMap.this.remove(o) != null;
}
@Override
public void clear() {
SelectableConcurrentHashMap.this.clear();
}
@Override
public Object[] toArray() {
Collection c = new ArrayList();
for (Object object : this)
c.add(object);
return c.toArray();
}
@Override
public T[] toArray(T[] a) {
Collection c = new ArrayList();
for (Object object : this)
c.add(object);
return c.toArray(a);
}
}
final class Values extends AbstractCollection {
@Override
public Iterator iterator() {
return new ValueIterator();
}
@Override
public int size() {
return SelectableConcurrentHashMap.this.size();
}
@Override
public boolean isEmpty() {
return SelectableConcurrentHashMap.this.isEmpty();
}
@Override
public boolean contains(Object o) {
return SelectableConcurrentHashMap.this.containsValue(o);
}
@Override
public void clear() {
SelectableConcurrentHashMap.this.clear();
}
@Override
public Object[] toArray() {
Collection c = new ArrayList();
for (Object object : this)
c.add(object);
return c.toArray();
}
@Override
public T[] toArray(T[] a) {
Collection c = new ArrayList();
for (Object object : this)
c.add(object);
return c.toArray(a);
}
}
final class EntrySet extends AbstractSet> {
@Override
public Iterator> iterator() {
return new EntryIterator();
}
@Override
public int size() {
return SelectableConcurrentHashMap.this.size();
}
@Override
public boolean isEmpty() {
return SelectableConcurrentHashMap.this.isEmpty();
}
@Override
public boolean contains(Object o) {
if (!(o instanceof Entry))
return false;
Entry e = (Entry)o;
Element v = SelectableConcurrentHashMap.this.get(e.getKey());
return v != null && v.equals(e.getValue());
}
@Override
public boolean remove(Object o) {
if (!(o instanceof Entry))
return false;
Entry e = (Entry)o;
return SelectableConcurrentHashMap.this.remove(e.getKey(), e.getValue());
}
@Override
public void clear() {
SelectableConcurrentHashMap.this.clear();
}
@Override
public Object[] toArray() {
Collection c = new ArrayList();
for (Object object : this)
c.add(object);
return c.toArray();
}
@Override
public T[] toArray(T[] a) {
Collection c = new ArrayList();
for (Object object : this)
c.add(object);
return c.toArray(a);
}
}
class KeyIterator extends HashEntryIterator implements Iterator {
@Override
public Object next() {
return nextEntry().key;
}
}
final class ValueIterator extends HashEntryIterator implements Iterator {
@Override
public Element next() {
return nextEntry().value;
}
}
final class EntryIterator extends HashEntryIterator implements Iterator> {
@Override
public Entry next() {
HashEntry entry = nextEntry();
final Object key = entry.key;
final Element value = entry.value;
return new Entry() {
public Object getKey() {
return key;
}
public Element getValue() {
return value;
}
public Element setValue(Element value) {
throw new UnsupportedOperationException();
}
};
}
}
abstract class HashEntryIterator extends HashIterator {
private HashEntry myNextEntry;
public HashEntryIterator() {
myNextEntry = advanceToNextEntry();
}
@Override
public void remove() {
throw new UnsupportedOperationException("remove is not supported");
}
@Override
public HashEntry nextEntry() {
if (myNextEntry == null) {
throw new NoSuchElementException();
}
HashEntry entry = myNextEntry;
myNextEntry = advanceToNextEntry();
return entry;
}
@Override
public boolean hasNext() {
return myNextEntry != null;
}
private HashEntry advanceToNextEntry() {
HashEntry myEntry = null;
while (super.hasNext()) {
myEntry = super.nextEntry();
if (myEntry != null) {
break;
} else {
myEntry = null;
}
}
return myEntry;
}
}
abstract class HashIterator {
int nextSegmentIndex;
int nextTableIndex;
HashEntry[] currentTable;
HashEntry nextEntry;
HashEntry lastReturned;
HashIterator() {
nextSegmentIndex = segments.length - 1;
nextTableIndex = -1;
advance();
}
final void advance() {
if (nextEntry != null && (nextEntry = nextEntry.next) != null)
return;
while (nextTableIndex >= 0) {
if ( (nextEntry = currentTable[nextTableIndex--]) != null)
return;
}
while (nextSegmentIndex >= 0) {
Segment seg = segments[nextSegmentIndex--];
if (seg.count != 0) {
currentTable = seg.table;
for (int j = currentTable.length - 1; j >= 0; --j) {
if ( (nextEntry = currentTable[j]) != null) {
nextTableIndex = j - 1;
return;
}
}
}
}
}
public boolean hasNext() { return nextEntry != null; }
HashEntry nextEntry() {
if (nextEntry == null)
throw new NoSuchElementException();
lastReturned = nextEntry;
advance();
return lastReturned;
}
public void remove() {
if (lastReturned == null)
throw new IllegalStateException();
SelectableConcurrentHashMap.this.remove(lastReturned.key);
lastReturned = null;
}
}
protected static int hash(int h) {
// Spread bits to regularize both segment and index locations,
// using variant of single-word Wang/Jenkins hash.
h += (h << 15) ^ 0xffffcd7d;
h ^= (h >>> 10);
h += (h << 3);
h ^= (h >>> 6);
h += (h << 2) + (h << 14);
return h ^ (h >>> 16);
}
}
