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Posted to commits@openjpa.apache.org by kw...@apache.org on 2008/06/26 21:31:21 UTC
svn commit: r672003 - in /openjpa/trunk:
openjpa-kernel/src/main/java/org/apache/openjpa/util/CacheMap.java
openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java
Author: kwsutter
Date: Thu Jun 26 12:31:20 2008
New Revision: 672003
URL: http://svn.apache.org/viewvc?rev=672003&view=rev
Log:
OPENJPA-637. Reverting ConcurrentHashMap implementation per the patch provided by Jeremy Bauer. A more complete, configurable implementation is being tracked via the related sub-task OPENJPA-643.
Added:
openjpa/trunk/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java (with props)
Modified:
openjpa/trunk/openjpa-kernel/src/main/java/org/apache/openjpa/util/CacheMap.java
Modified: openjpa/trunk/openjpa-kernel/src/main/java/org/apache/openjpa/util/CacheMap.java
URL: http://svn.apache.org/viewvc/openjpa/trunk/openjpa-kernel/src/main/java/org/apache/openjpa/util/CacheMap.java?rev=672003&r1=672002&r2=672003&view=diff
==============================================================================
--- openjpa/trunk/openjpa-kernel/src/main/java/org/apache/openjpa/util/CacheMap.java (original)
+++ openjpa/trunk/openjpa-kernel/src/main/java/org/apache/openjpa/util/CacheMap.java Thu Jun 26 12:31:20 2008
@@ -22,7 +22,6 @@
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
-import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
@@ -31,12 +30,10 @@
import org.apache.commons.collections.iterators.FilterIterator;
import org.apache.commons.collections.iterators.IteratorChain;
import org.apache.openjpa.lib.util.LRUMap;
-import org.apache.openjpa.lib.util.ReferenceHashMap;
import org.apache.openjpa.lib.util.ReferenceMap;
import org.apache.openjpa.lib.util.SizedMap;
+import org.apache.openjpa.lib.util.concurrent.ConcurrentHashMap;
import org.apache.openjpa.lib.util.concurrent.ConcurrentReferenceHashMap;
-import org.apache.openjpa.lib.util.concurrent.NullSafeConcurrentHashMap;
-import org.apache.openjpa.lib.util.concurrent.SizedConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;
@@ -114,10 +111,10 @@
softMapValueExpired(key);
}
};
- pinnedMap = new NullSafeConcurrentHashMap();
+ pinnedMap = new ConcurrentHashMap();
if (!lru) {
- cacheMap = new SizedConcurrentHashMap(size, load, concurrencyLevel){
+ cacheMap = new ConcurrentHashMap(size, load) {
public void overflowRemoved(Object key, Object value) {
cacheMapOverflowRemoved(key, value);
}
Added: openjpa/trunk/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java
URL: http://svn.apache.org/viewvc/openjpa/trunk/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java?rev=672003&view=auto
==============================================================================
--- openjpa/trunk/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java (added)
+++ openjpa/trunk/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java Thu Jun 26 12:31:20 2008
@@ -0,0 +1,941 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.openjpa.lib.util.concurrent;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.util.AbstractCollection;
+import java.util.AbstractMap;
+import java.util.AbstractSet;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Random;
+import java.util.Set;
+
+import org.apache.openjpa.lib.util.SizedMap;
+
+/**
+ * This class implements a HashMap which has limited synchronization.
+ * In particular mutators are generally synchronized while accessors
+ * are generally not. Additionally the Iterators returned by this
+ * class are not "fail-fast", but instead try to continue to iterate
+ * over the data structure after changes have been made.
+ * The synchronization semantics are built right in to the
+ * implementation rather than using a delegating wrapper like the
+ * other collection classes do because it wasn't clear to me that the
+ * how the two should be seperated or that it would be useful to do
+ * so. This can probably be a topic for further debate in the future.
+ * This class is based heavily on the HashMap class in the Java
+ * collections package.
+ */
+public class ConcurrentHashMap extends AbstractMap
+ implements ConcurrentMap, SizedMap, Cloneable, Serializable {
+
+ /**
+ * The default initial capacity - MUST be a power of two.
+ */
+ private static final int DEFAULT_INITIAL_CAPACITY = 16;
+
+ /**
+ * 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.
+ */
+ private static final int MAXIMUM_CAPACITY = 1 << 30;
+
+ /**
+ * The load fast used when none specified in constructor.
+ */
+ private static final float DEFAULT_LOAD_FACTOR = 0.75f;
+
+ /**
+ * Cache of random numbers used in "random" methods, since generating them
+ * is expensive. We hope each map changes enough between cycling through
+ * this list that the overall effect is random enough.
+ */
+ static final double[] RANDOMS = new double[1000];
+
+ static {
+ Random random = new Random();
+ for (int i = 0; i < RANDOMS.length; i++)
+ RANDOMS[i] = random.nextDouble();
+ }
+
+ /**
+ * The table, resized as necessary. Length MUST Always be a power of two.
+ */
+ private transient Entry[] table;
+
+ /**
+ * The number of key-value mappings contained in this identity hash map.
+ */
+ private transient int size;
+
+ /**
+ * The next size value at which to resize(capacity * load factor).
+ *
+ * @serial
+ */
+ private int threshold;
+
+ /**
+ * The load factor for the hash table.
+ *
+ * @serial
+ */
+ private final float loadFactor;
+
+ /**
+ * Spread "random" removes and iteration.
+ */
+ private int randomEntry = 0;
+
+ /**
+ * Maximum entries.
+ */
+ private int maxSize = Integer.MAX_VALUE;
+
+ /**
+ * Constructs an empty <tt>ConcurrentHashMap</tt> with the specified initial
+ * capacity and load factor.
+ *
+ * @param initialCapacity The initial capacity.
+ * @param loadFactor The load factor.
+ * @throws IllegalArgumentException if the initial capacity is negative
+ * or the load factor is nonpositive.
+ */
+ public ConcurrentHashMap(int initialCapacity, float loadFactor) {
+ if (initialCapacity < 0) {
+ throw new IllegalArgumentException("Illegal initial capacity: " +
+ initialCapacity);
+ }
+ if (initialCapacity > MAXIMUM_CAPACITY)
+ initialCapacity = MAXIMUM_CAPACITY;
+ if (loadFactor <= 0 || loadFactor > 1) {
+ throw new IllegalArgumentException("Illegal load factor: " +
+ loadFactor);
+ }
+
+ // Find a power of 2 >= initialCapacity
+ int capacity = 1;
+ while (capacity < initialCapacity) capacity <<= 1;
+
+ this.loadFactor = loadFactor;
+ threshold = (int) (capacity * loadFactor);
+ table = new Entry[capacity];
+ }
+
+ /**
+ * Constructs an empty <tt>ConcurrentHashMap</tt> with the specified initial
+ * capacity and the default load factor(0.75).
+ *
+ * @param initialCapacity the initial capacity.
+ * @throws IllegalArgumentException if the initial capacity is negative.
+ */
+ public ConcurrentHashMap(int initialCapacity) {
+ this(initialCapacity, DEFAULT_LOAD_FACTOR);
+ }
+
+ /**
+ * Constructs an empty <tt>ConcurrentHashMap</tt> with the default initial
+ * capacity(16) and the default load factor(0.75).
+ */
+ public ConcurrentHashMap() {
+ this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR);
+ }
+
+ /**
+ * Constructs a new <tt>ConcurrentHashMap</tt> with the same mappings as the
+ * specified <tt>Map</tt>. The <tt>ConcurrentHashMap</tt> is created with
+ * default load factor(0.75) and an initial capacity sufficient to
+ * hold the mappings in the specified <tt>Map</tt>.
+ *
+ * @param m the map whose mappings are to be placed in this map.
+ * @throws NullPointerException if the specified map is null.
+ */
+ public ConcurrentHashMap(Map m) {
+ this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
+ DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR);
+ putAll(m);
+ }
+
+ // internal utilities
+
+ /**
+ * Value representing null keys inside tables.
+ */
+ private static final Object NULL_KEY = new Object();
+
+ /**
+ * Returns internal representation for key. Use NULL_KEY if key is null.
+ */
+ private static Object maskNull(Object key) {
+ return (key == null ? NULL_KEY : key);
+ }
+
+ /**
+ * Returns key represented by specified internal representation.
+ */
+ private static Object unmaskNull(Object key) {
+ return (key == NULL_KEY ? null : key);
+ }
+
+ /**
+ * Returns a hash code for non-null Object x.
+ */
+ private static int hash(Object x) {
+ int h = x.hashCode();
+ return h - (h << 7); // i.e., -127 * h
+ }
+
+ /**
+ * Check for equality of non-null reference x and possibly-null y.
+ */
+ private static boolean eq(Object x, Object y) {
+ return x == y || x.equals(y);
+ }
+
+ /**
+ * Returns the current capacity of backing table in this map.
+ *
+ * @return the current capacity of backing table in this map.
+ */
+ public final int capacity() {
+ return table.length;
+ }
+
+ /**
+ * Returns the load factor for this map.
+ *
+ * @return the load factor for this map.
+ */
+ public final float loadFactor() {
+ return loadFactor;
+ }
+
+ public int getMaxSize() {
+ return maxSize;
+ }
+
+ public void setMaxSize(int maxSize) {
+ this.maxSize = (maxSize < 0) ? Integer.MAX_VALUE : maxSize;
+ if (this.maxSize != Integer.MAX_VALUE)
+ removeOverflow(this.maxSize);
+ }
+
+ public boolean isFull() {
+ return maxSize != Integer.MAX_VALUE && size() >= maxSize;
+ }
+
+ public void overflowRemoved(Object key, Object value) {
+ }
+
+ /**
+ * Returns the number of key-value mappings in this map.
+ *
+ * @return the number of key-value mappings in this map.
+ */
+ public final int size() {
+ return size;
+ }
+
+ /**
+ * Returns <tt>true</tt> if this map contains no key-value mappings.
+ *
+ * @return <tt>true</tt> if this map contains no key-value mappings.
+ */
+ public final boolean isEmpty() {
+ return size == 0;
+ }
+
+ /**
+ * Returns the value to which the specified key is mapped in this identity
+ * hash map, or <tt>null</tt> if the map contains no mapping for this key.
+ * A return value of <tt>null</tt> does not <i>necessarily</i> indicate
+ * that the map contains no mapping for the key; it is also possible that
+ * the map explicitly maps the key to <tt>null</tt>. The
+ * <tt>containsKey</tt> method may be used to distinguish these two cases.
+ *
+ * @param key the key whose associated value is to be returned.
+ * @return the value to which this map maps the specified key, or
+ * <tt>null</tt> if the map contains no mapping for this key.
+ * @see #put(Object, Object)
+ */
+ public Object get(Object key) {
+ Entry e = getEntry(key);
+ return e == null ? null : e.value;
+ }
+
+ /**
+ * Returns <tt>true</tt> if this map contains a mapping for the
+ * specified key.
+ *
+ * @param key The key whose presence in this map is to be tested
+ * @return <tt>true</tt> if this map contains a mapping for the specified
+ * key.
+ */
+ public final boolean containsKey(Object key) {
+ return getEntry(key) != null;
+ }
+
+ /**
+ * Returns the entry associated with the specified key in the
+ * ConcurrentHashMap. Returns null if the ConcurrentHashMap contains no
+ * mapping for this key.
+ */
+ protected Entry getEntry(Object key) {
+ Object k = maskNull(key);
+ int hash = hash(k);
+ Entry[] tab = table;
+ for (Entry e = tab[hash & (tab.length - 1)]; e != null; e = e.next) {
+ if (e.hash == hash && eq(k, e.key)) return e;
+ }
+ return null;
+ }
+
+ /**
+ * Associates the specified value with the specified key in this map.
+ * If the map previously contained a mapping for this key, the old
+ * value is replaced.
+ *
+ * @param key key with which the specified value is to be associated.
+ * @param value value to be associated with the specified key.
+ * @return previous value associated with specified key, or <tt>null</tt>
+ * if there was no mapping for key. A <tt>null</tt> return can
+ * also indicate that the ConcurrentHashMap previously associated
+ * <tt>null</tt> with the specified key.
+ */
+ public Object put(Object key, Object value) {
+ Object k = maskNull(key);
+ int hash = hash(k);
+ synchronized (this) {
+ int i = hash & (table.length - 1);
+
+ for (Entry e = table[i]; e != null; e = e.next) {
+ if (e.hash == hash && eq(k, e.key)) {
+ Object oldValue = e.value;
+ e.value = value;
+ return oldValue;
+ }
+ }
+
+ if (maxSize != Integer.MAX_VALUE)
+ removeOverflow(maxSize - 1);
+ table[i] = createEntry(hash, k, value, table[i]);
+ if (size++ >= threshold) resize(2 * table.length);
+ }
+ return null;
+ }
+
+ /**
+ * Remove any entries equal to or over the max size.
+ */
+ private void removeOverflow(int maxSize) {
+ while (size > maxSize) {
+ Map.Entry entry = removeRandom();
+ if (entry == null)
+ break;
+ overflowRemoved(entry.getKey(), entry.getValue());
+ }
+ }
+
+ public Object putIfAbsent(Object key, Object value) {
+ Object k = maskNull(key);
+ int hash = hash(k);
+ synchronized (this) {
+ int i = hash & (table.length - 1);
+
+ for (Entry e = table[i]; e != null; e = e.next) {
+ if (e.hash == hash && eq(k, e.key)) {
+ return e.value;
+ }
+ }
+
+ if (maxSize != Integer.MAX_VALUE)
+ removeOverflow(maxSize - 1);
+ table[i] = createEntry(hash, k, value, table[i]);
+ if (size++ >= threshold) resize(2 * table.length);
+ }
+ return null;
+ }
+
+ /**
+ * Rehashes the contents of this map into a new <tt>ConcurrentHashMap</tt>
+ * instance with a larger capacity. This method is called automatically when
+ * the number of keys in this map exceeds its capacity and load factor.
+ *
+ * @param newCapacity the new capacity, MUST be a power of two.
+ */
+ private void resize(int newCapacity) {
+ // assert(newCapacity & -newCapacity) == newCapacity; // power of 2
+ Entry[] oldTable = table;
+ int oldCapacity = oldTable.length;
+
+ // check if needed
+ if (size < threshold || oldCapacity > newCapacity) return;
+
+ Entry[] newTable = new Entry[newCapacity];
+ int mask = newCapacity - 1;
+ for (int i = oldCapacity; i-- > 0;) {
+ for (Entry e = oldTable[i]; e != null; e = e.next) {
+ Entry clone = (Entry) e.clone();
+ int j = clone.hash & mask;
+ clone.next = newTable[j];
+ newTable[j] = clone;
+ }
+ }
+ table = newTable;
+ threshold = (int) (newCapacity * loadFactor);
+ }
+
+ /**
+ * Copies all of the mappings from the specified map to this map
+ * These mappings will replace any mappings that
+ * this map had for any of the keys currently in the specified map.
+ *
+ * @param t mappings to be stored in this map.
+ * @throws NullPointerException if the specified map is null.
+ */
+ public final synchronized void putAll(Map t) {
+ // Expand enough to hold t's elements without resizing.
+ int n = t.size();
+ if (n == 0) return;
+ if (n >= threshold) {
+ n = (int) (n / loadFactor + 1);
+ if (n > MAXIMUM_CAPACITY) n = MAXIMUM_CAPACITY;
+ int capacity = table.length;
+ while (capacity < n) capacity <<= 1;
+ resize(capacity);
+ }
+
+ for (Iterator i = t.entrySet().iterator(); i.hasNext();) {
+ Map.Entry e = (Map.Entry) i.next();
+ put(e.getKey(), e.getValue());
+ }
+ }
+
+ /**
+ * Removes the mapping for this key from this map if present.
+ *
+ * @param key key whose mapping is to be removed from the map.
+ * @return previous value associated with specified key, or <tt>null</tt>
+ * if there was no mapping for key. A <tt>null</tt> return can
+ * also indicate that the map previously associated <tt>null</tt>
+ * with the specified key.
+ */
+ public Object remove(Object key) {
+ Entry e = removeEntryForKey(key);
+ return (e == null ? e : e.value);
+ }
+
+ /**
+ * Removes and returns the entry associated with the specified key in the
+ * ConcurrentHashMap. Returns null if the ConcurrentHashMap contains no
+ * mapping for this key.
+ */
+ private Entry removeEntryForKey(Object key) {
+ Object k = maskNull(key);
+ int hash = hash(k);
+ synchronized (this) {
+ int i = hash & (table.length - 1);
+ Entry e = table[i];
+
+ if (e == null) return null;
+ if (e.hash == hash && eq(k, e.key)) {
+ size--;
+ table[i] = e.next;
+ return e;
+ }
+
+ Entry prev = e;
+ for (e = e.next; e != null; prev = e, e = e.next) {
+ if (e.hash == hash && eq(k, e.key)) {
+ size--;
+ prev.next = e.next;
+ return e;
+ }
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Special version of remove for EntrySet.
+ */
+ private Entry removeMapping(Object o) {
+ if (!(o instanceof Map.Entry)) return null;
+
+ Map.Entry entry = (Map.Entry) o;
+ Object k = maskNull(entry.getKey());
+ int hash = hash(k);
+ synchronized (this) {
+ int i = hash & (table.length - 1);
+ Entry e = table[i];
+
+ if (e == null) return null;
+ if (e.hash == hash && e.equals(entry)) {
+ size--;
+ table[i] = e.next;
+ return e;
+ }
+
+ Entry prev = e;
+ for (e = e.next; e != null; prev = e, e = e.next) {
+ if (e.hash == hash && e.equals(entry)) {
+ size--;
+ prev.next = e.next;
+ return e;
+ }
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Removes all mappings from this map.
+ */
+ public synchronized void clear() {
+ table = new Entry[table.length];
+ size = 0;
+ }
+
+ /**
+ * Return an arbitrary entry index.
+ */
+ private int randomEntryIndex() {
+ if (randomEntry == RANDOMS.length)
+ randomEntry = 0;
+ return (int) (RANDOMS[randomEntry++] * table.length);
+ }
+
+ public Map.Entry removeRandom() {
+ if (size == 0)
+ return null;
+
+ synchronized (this) {
+ int random = randomEntryIndex();
+ int index = findEntry(random, random % 2 == 0, false);
+ if (index == -1)
+ return null;
+ Entry rem = table[index];
+ table[index] = rem.next;
+ size--;
+ return rem;
+ }
+ }
+
+ /**
+ * Find the index of the entry nearest the given index, starting in the
+ * given direction.
+ */
+ private int findEntry(int start, boolean forward, boolean searchedOther) {
+ if (forward) {
+ for (int i = start; i < table.length; i++)
+ if (table[i] != null)
+ return i;
+ return (searchedOther || start == 0) ? -1
+ : findEntry(start - 1, false, true);
+ } else {
+ for (int i = start; i >= 0; i--)
+ if (table[i] != null)
+ return i;
+ return (searchedOther || start == table.length - 1) ? -1
+ : findEntry(start + 1, true, true);
+ }
+ }
+
+ public Iterator randomEntryIterator() {
+ // pass index so calculated before iterator refs table, in case table
+ // gets replace with a larger one
+ return new HashIterator(ENTRIES, randomEntryIndex());
+ }
+
+ /**
+ * Returns <tt>true</tt> if this map maps one or more keys to the
+ * specified value.
+ *
+ * @param value value whose presence in this map is to be tested.
+ * @return <tt>true</tt> if this map maps one or more keys to the
+ * specified value.
+ */
+ public final boolean containsValue(Object value) {
+ if (value == null) return containsNullValue();
+
+ Entry tab[] = table;
+ for (int i = 0; i < tab.length; i++) {
+ for (Entry e = tab[i]; e != null; e = e.next) {
+ if (value.equals(e.value)) return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Special-case code for containsValue with null argument
+ */
+ private boolean containsNullValue() {
+ Entry tab[] = table;
+ for (int i = 0; i < tab.length; i++) {
+ for (Entry e = tab[i]; e != null; e = e.next) {
+ if (e.value == null) return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Returns a shallow copy of this <tt>ConcurrentHashMap</tt> instance: the
+ * keys and values themselves are not cloned.
+ *
+ * @return a shallow copy of this map.
+ */
+ public final Object clone() {
+ return new ConcurrentHashMap(this);
+ }
+
+ protected Entry createEntry(int h, Object k, Object v, Entry n) {
+ return new Entry(h, k, v, n);
+ }
+
+ protected static class Entry implements Map.Entry {
+
+ final Object key;
+ Object value;
+ final int hash;
+ Entry next;
+
+ /**
+ * Create new entry.
+ */
+ protected Entry(int h, Object k, Object v, Entry n) {
+ value = v;
+ next = n;
+ key = k;
+ hash = h;
+ }
+
+ public Object getKey() {
+ return unmaskNull(key);
+ }
+
+ public Object getValue() {
+ return value;
+ }
+
+ public Object setValue(Object newValue) {
+ Object oldValue = value;
+ value = newValue;
+ return oldValue;
+ }
+
+ public boolean equals(Object o) {
+ if (!(o instanceof Map.Entry)) return false;
+ Map.Entry e = (Map.Entry) o;
+ Object k1 = getKey();
+ Object k2 = e.getKey();
+ if (k1 == k2 || (k1 != null && k1.equals(k2))) {
+ Object v1 = getValue();
+ Object v2 = e.getValue();
+ if (v1 == v2 || (v1 != null && v1.equals(v2)))
+ return true;
+ }
+ return false;
+ }
+
+ public int hashCode() {
+ return (key == NULL_KEY ? 0 : key.hashCode()) ^
+ (value == null ? 0 : value.hashCode());
+ }
+
+ public String toString() {
+ return getKey() + "=" + getValue();
+ }
+
+ protected Object clone() {
+ // It is the callers responsibility to set the next field
+ // correctly.
+ return new Entry(hash, key, value, null);
+ }
+ }
+
+ // Types of Enumerations/Iterations
+ private static final int KEYS = 0;
+ private static final int VALUES = 1;
+ private static final int ENTRIES = 2;
+
+ /**
+ * Map iterator.
+ */
+ private class HashIterator implements Iterator {
+
+ final Entry[] table = ConcurrentHashMap.this.table;
+ final int type;
+ int startIndex;
+ int stopIndex = 0;
+ int index;
+ Entry entry = null;
+ Entry lastReturned = null;
+
+ HashIterator(int type, int startIndex) {
+ this.type = type;
+ this.startIndex = startIndex;
+ index = startIndex;
+ }
+
+ public boolean hasNext() {
+ if (entry != null) {
+ return true;
+ }
+ while (index >= stopIndex) {
+ if ((entry = table[index--]) != null) {
+ return true;
+ }
+ }
+ if (stopIndex == 0) {
+ index = table.length - 1;
+ stopIndex = startIndex + 1;
+ while (index >= stopIndex) {
+ if ((entry = table[index--]) != null) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ public Object next() {
+ if (!hasNext())
+ throw new NoSuchElementException();
+ Entry e = lastReturned = entry;
+ entry = e.next;
+ return type == KEYS ? e.key : (type == VALUES ? e.value : e);
+ }
+
+ public void remove() {
+ if (lastReturned == null)
+ throw new IllegalStateException();
+ synchronized (ConcurrentHashMap.this) {
+ Entry[] tab = ConcurrentHashMap.this.table;
+ int index = (lastReturned.hash & 0x7FFFFFFF) % tab.length;
+
+ for (Entry e = tab[index], prev = null; e != null;
+ prev = e, e = e.next) {
+ if (e == lastReturned) {
+ if (prev == null)
+ tab[index] = e.next;
+ else
+ prev.next = e.next;
+ size--;
+ lastReturned = null;
+ return;
+ }
+ }
+ throw new Error("Iterated off table when doing remove");
+ }
+ }
+ }
+
+ // Views
+
+ private transient Set entrySet = null;
+ private transient Set keySet = null;
+ private transient Collection values = null;
+
+ /**
+ * Returns a set view of the keys contained in this map. The set is
+ * backed by the map, so changes to the map are reflected in the set, and
+ * vice-versa. The set supports element removal, which removes the
+ * corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
+ * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
+ * <tt>clear</tt> operations. It does not support the <tt>add</tt> or
+ * <tt>addAll</tt> operations.
+ *
+ * @return a set view of the keys contained in this map.
+ */
+ public final Set keySet() {
+ Set ks = keySet;
+ return (ks != null ? ks : (keySet = new KeySet()));
+ }
+
+ private final class KeySet extends AbstractSet {
+
+ public Iterator iterator() {
+ return new HashIterator(KEYS, table.length - 1);
+ }
+
+ public int size() {
+ return size;
+ }
+
+ public boolean contains(Object o) {
+ return containsKey(o);
+ }
+
+ public boolean remove(Object o) {
+ return ConcurrentHashMap.this.removeEntryForKey(o) != null;
+ }
+
+ public void clear() {
+ ConcurrentHashMap.this.clear();
+ }
+ }
+
+ /**
+ * Returns a collection view of the values contained in this map. The
+ * collection is backed by the map, so changes to the map are reflected in
+ * the collection, and vice-versa. The collection supports element
+ * removal, which removes the corresponding mapping from this map, via the
+ * <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
+ * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
+ * It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
+ *
+ * @return a collection view of the values contained in this map.
+ */
+ public final Collection values() {
+ Collection vs = values;
+ return (vs != null ? vs : (values = new Values()));
+ }
+
+ private final class Values extends AbstractCollection {
+
+ public Iterator iterator() {
+ return new HashIterator(VALUES, table.length - 1);
+ }
+
+ public int size() {
+ return size;
+ }
+
+ public boolean contains(Object o) {
+ return containsValue(o);
+ }
+
+ public void clear() {
+ ConcurrentHashMap.this.clear();
+ }
+ }
+
+ /**
+ * Returns a collection view of the mappings contained in this map. Each
+ * element in the returned collection is a <tt>Map.Entry</tt>. The
+ * collection is backed by the map, so changes to the map are reflected in
+ * the collection, and vice-versa. The collection supports element
+ * removal, which removes the corresponding mapping from the map, via the
+ * <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
+ * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
+ * It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
+ *
+ * @return a collection view of the mappings contained in this map.
+ * @see Map.Entry
+ */
+ public final Set entrySet() {
+ Set es = entrySet;
+ return (es != null ? es : (entrySet = new EntrySet()));
+ }
+
+ private final class EntrySet extends AbstractSet {
+
+ public Iterator iterator() {
+ return new HashIterator(ENTRIES, table.length - 1);
+ }
+
+ public boolean contains(Object o) {
+ if (!(o instanceof Map.Entry)) return false;
+ Map.Entry e = (Map.Entry) o;
+ Entry candidate = getEntry(e.getKey());
+ return candidate != null && candidate.equals(e);
+ }
+
+ public boolean remove(Object o) {
+ return removeMapping(o) != null;
+ }
+
+ public int size() {
+ return size;
+ }
+
+ public void clear() {
+ ConcurrentHashMap.this.clear();
+ }
+ }
+
+ /**
+ * Save the state of the <tt>ConcurrentHashMap</tt> instance to a stream
+ * (i.e., serialize it).
+ *
+ * @serialData The <i>capacity</i> of the ConcurrentHashMap(the length of
+ * the bucket array) is emitted(int), followed by the <i>size</i> of the
+ * ConcurrentHashMap(the number of key-value mappings), followed by the key
+ * (Object) and value(Object) for each key-value mapping represented by the
+ * ConcurrentHashMap The key-value mappings are emitted in the order that
+ * they are returned by <tt>entrySet().iterator()</tt>.
+ */
+ private void writeObject(ObjectOutputStream s) throws IOException {
+ // Write out the threshold, loadfactor, and any hidden stuff
+ s.defaultWriteObject();
+
+ // Write out number of buckets
+ s.writeInt(table.length);
+
+ // Write out size(number of Mappings)
+ s.writeInt(size);
+ s.writeInt(maxSize);
+
+ // Write out keys and values(alternating)
+ for (Iterator i = entrySet().iterator(); i.hasNext();) {
+ Map.Entry e = (Map.Entry) i.next();
+ s.writeObject(e.getKey());
+ s.writeObject(e.getValue());
+ }
+ }
+
+ private static final long serialVersionUID = -6452706556724125778L;
+
+ /**
+ * Reconstitute the <tt>ConcurrentHashMap</tt> instance from a stream(i.e.,
+ * deserialize it).
+ */
+ private void readObject(ObjectInputStream s)
+ throws IOException, ClassNotFoundException {
+ // Read in the threshold, loadfactor, and any hidden stuff
+ s.defaultReadObject();
+
+ // Read in number of buckets and allocate the bucket array;
+ int numBuckets = s.readInt();
+ table = new Entry[numBuckets];
+
+ // Read in size(number of Mappings)
+ int size = s.readInt();
+
+ // read the max size
+ maxSize = s.readInt();
+
+ // Read the keys and values, and put the mappings in the
+ // ConcurrentHashMap
+ for (int i = 0; i < size; i++) {
+ Object key = s.readObject();
+ Object value = s.readObject();
+ put(key, value);
+ }
+ }
+}
Propchange: openjpa/trunk/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/concurrent/ConcurrentHashMap.java
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