mirror of
https://github.com/apache/openjpa.git
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removing unused file
git-svn-id: https://svn.apache.org/repos/asf/incubator/openjpa/trunk@406418 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Patrick Linskey
parent
42cbc4dd74
commit
e6584f2f74
@ -1,965 +0,0 @@
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/*
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* Copyright 2006 The Apache Software Foundation.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.openjpa.lib.util;
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/*
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* @author Copyright (c) 1997 by WebLogic, Inc. All Rights Reserved.
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*/
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import java.io.*;
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import java.util.*;
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/** This class implements a HashMap which has limited synchronization.
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* In particular mutators are generally synchronized while accessors
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* are generally not. Additionally the Iterators returned by this
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* class are not "fail-fast", but instead try to continue to iterate
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* over the data structure after changes have been made.
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*
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* The synchronization semantics are built right in to the
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* implementation rather than using a delegating wrapper like the
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* other collection classes do because it wasn't clear to me that the
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* how the two should be seperated or that it would be useful to do
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* so. This can probably be a topic for further debate in the
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* future.
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*
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* This class is based heavily on the HashMap class in the Java
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* collections package. */
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public class ConcurrentHashMap extends AbstractMap
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implements Map, Cloneable, Serializable
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{
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private static Localizer _loc = Localizer.forPackage
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(ConcurrentHashMap.class);
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/**
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* The default initial capacity - MUST be a power of two.
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*/
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private static final int DEFAULT_INITIAL_CAPACITY = 16;
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/**
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* The maximum capacity, used if a higher value is implicitly specified
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* by either of the constructors with arguments.
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* MUST be a power of two <= 1<<30.
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*/
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private static final int MAXIMUM_CAPACITY = 1 << 30;
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/**
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* The load fast used when none specified in constructor.
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**/
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private static final float DEFAULT_LOAD_FACTOR = 0.75f;
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/**
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* Value representing null keys inside tables.
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*/
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private static final Object NULL_KEY = new Object ();
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/**
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* The table, resized as necessary. Length MUST Always be a power of two.
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*/
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private transient Entry[] table;
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/**
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* The number of key-value mappings contained in this identity hash map.
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*/
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private transient int size;
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/**
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* The next size value at which to resize (capacity * load factor).
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* @serial
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*/
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private int threshold;
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/**
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* The load factor for the hash table.
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*
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* @serial
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*/
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private final float loadFactor;
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/**
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* Constructs an empty <tt>ConcurrentHashMap</tt> with the specified initial
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* capacity and load factor.
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*
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* @param initialCapacity The initial capacity.
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* @param loadFactor The load factor.
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* @throws IllegalArgumentException if the initial capacity is negative
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* or the load factor is nonpositive.
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*/
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public ConcurrentHashMap (int initialCapacity, float loadFactor)
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{
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if (initialCapacity < 0)
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{
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throw new IllegalArgumentException (_loc.get ("concurrent-initial",
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initialCapacity + ""));
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}
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if (initialCapacity > MAXIMUM_CAPACITY)
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initialCapacity = MAXIMUM_CAPACITY;
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if (loadFactor <= 0 || loadFactor > 1)
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{
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throw new IllegalArgumentException (_loc.get ("concurrent-load",
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loadFactor + ""));
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}
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// Find a power of 2 >= initialCapacity
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int capacity = 1;
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while (capacity < initialCapacity) capacity <<= 1;
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this.loadFactor = loadFactor;
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threshold = (int) (capacity * loadFactor);
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table = new Entry[capacity];
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}
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/**
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* Constructs an empty <tt>ConcurrentHashMap</tt> with the specified initial
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* capacity and the default load factor (0.75).
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*
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* @param initialCapacity the initial capacity.
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* @throws IllegalArgumentException if the initial capacity is negative.
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*/
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public ConcurrentHashMap (int initialCapacity)
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{
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this (initialCapacity, DEFAULT_LOAD_FACTOR);
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}
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/**
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* Constructs an empty <tt>ConcurrentHashMap</tt> with the default initial
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* capacity (16) and the default load factor (0.75).
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*/
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public ConcurrentHashMap ()
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{
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this (DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR);
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}
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/**
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* Constructs a new <tt>ConcurrentHashMap</tt> with the same mappings as the
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* specified <tt>Map</tt>. The <tt>ConcurrentHashMap</tt> is created with
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* default load factor (0.75) and an initial capacity sufficient to
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* hold the mappings in the specified <tt>Map</tt>.
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*
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* @param m the map whose mappings are to be placed in this map.
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* @throws NullPointerException if the specified map is null.
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*/
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public ConcurrentHashMap (Map m)
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{
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this (Math.max ( (int) (m.size () / DEFAULT_LOAD_FACTOR) + 1,
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DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR);
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putAll (m);
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}
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// internal utilities
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/**
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* Returns internal representation for key. Use NULL_KEY if key is null.
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*/
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private static Object maskNull (Object key)
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{
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return (key == null ? NULL_KEY : key);
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}
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/**
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* Returns key represented by specified internal representation.
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*/
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private static Object unmaskNull (Object key)
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{
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return (key == NULL_KEY ? null : key);
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}
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/**
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* Returns a hash code for non-null Object x.
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*/
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private static int hash (Object x)
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{
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int h = x.hashCode ();
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return h - (h << 7); // i.e., -127 * h
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}
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/**
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* Check for equality of non-null reference x and possibly-null y.
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*/
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private static boolean eq (Object x, Object y)
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{
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return x == y || x.equals (y);
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}
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/**
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* Returns the current capacity of backing table in this map.
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*
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* @return the current capacity of backing table in this map.
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*/
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public final int capacity ()
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{
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return table.length;
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}
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/**
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* Returns the load factor for this map.
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*
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* @return the load factor for this map.
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*/
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public final float loadFactor ()
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{
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return loadFactor;
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}
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/**
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* Returns the number of key-value mappings in this map.
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*
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* @return the number of key-value mappings in this map.
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*/
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public final int size ()
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{
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return size;
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}
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/**
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* Returns <tt>true</tt> if this map contains no key-value mappings.
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*
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* @return <tt>true</tt> if this map contains no key-value mappings.
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*/
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public final boolean isEmpty ()
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{
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return size == 0;
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}
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/**
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* Returns the value to which the specified key is mapped in this identity
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* hash map, or <tt>null</tt> if the map contains no mapping for this key.
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* A return value of <tt>null</tt> does not <i>necessarily</i> indicate
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* that the map contains no mapping for the key; it is also possible that
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* the map explicitly maps the key to <tt>null</tt>. The
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* <tt>containsKey</tt> method may be used to distinguish these two cases.
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*
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* @param key the key whose associated value is to be returned.
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* @return the value to which this map maps the specified key, or
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* <tt>null</tt> if the map contains no mapping for this
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key.
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* @see #put (Object, Object)
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*/
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public Object get (Object key)
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{
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Entry e = getEntry (key);
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return e == null? null: e.value;
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}
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/**
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* Returns <tt>true</tt> if this map contains a mapping for the
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* specified key.
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*
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* @param key The key whose presence in this map is to be tested
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* @return <tt>true</tt> if this map contains a mapping for the specified
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* key.
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*/
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public final boolean containsKey (Object key)
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{
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return getEntry (key) != null;
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}
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/**
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* Returns the entry associated with the specified key in the
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* ConcurrentHashMap. Returns null if the ConcurrentHashMap contains no
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* mapping for this key.
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*/
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protected Entry getEntry (Object key)
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{
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Object k = maskNull (key);
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int hash = hash (k);
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Entry[] tab = table;
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for (Entry e = tab[hash & (tab.length-1)]; e != null; e = e.next)
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{
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if (e.hash == hash && eq (k, e.key)) return e;
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}
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return null;
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}
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/**
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* Associates the specified value with the specified key in this map.
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* If the map previously contained a mapping for this key, the old
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* value is replaced.
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*
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* @param key key with which the specified value is to be associated.
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* @param value value to be associated with the specified key.
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* @return previous value associated with specified key, or <tt>null</tt>
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* if there was no mapping for key. A <tt>null</tt> return
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* can also indicate that the ConcurrentHashMap previously
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* associated
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* <tt>null</tt> with the specified key.
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*/
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public Object put (Object key, Object value)
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{
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Object k = maskNull (key);
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int hash = hash (k);
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synchronized (this)
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{
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int i = hash & (table.length - 1);
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for (Entry e = table[i]; e != null; e = e.next)
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{
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if (e.hash == hash && eq (k, e.key))
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{
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Object oldValue = e.value;
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e.value = value;
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return oldValue;
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}
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}
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table[i] = createEntry (hash, k, value, table[i]);
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if (size++ >= threshold) resize (2 * table.length);
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}
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return null;
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}
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public Object putIfAbsent (Object key, Object value)
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{
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Object k = maskNull (key);
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int hash = hash (k);
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synchronized (this)
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{
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int i = hash & (table.length - 1);
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for (Entry e = table[i]; e != null; e = e.next)
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{
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if (e.hash == hash && eq (k, e.key))
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{
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return e.value;
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}
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}
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table[i] = createEntry (hash, k, value, table[i]);
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if (size++ >= threshold) resize (2 * table.length);
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}
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return null;
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}
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/**
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* Rehashes the contents of this map into a new <tt>ConcurrentHashMap</tt>
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* instance with a larger capacity. This method is called automatically when
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* the number of keys in this map exceeds its capacity and load factor.
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*
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* @param newCapacity the new capacity, MUST be a power of two.
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*/
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private void resize (int newCapacity)
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{
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// assert (newCapacity & -newCapacity) == newCapacity; // power of 2
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Entry[] oldTable = table;
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int oldCapacity = oldTable.length;
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// check if needed
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if (size < threshold || oldCapacity > newCapacity) return;
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Entry[] newTable = new Entry[newCapacity];
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int mask = newCapacity-1;
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for (int i = oldCapacity; i-- > 0; )
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{
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for (Entry e = oldTable[i]; e != null; e = e.next)
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{
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Entry clone = (Entry) e.clone ();
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int j = clone.hash & mask;
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clone.next = newTable[j];
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newTable[j] = clone;
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}
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}
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table = newTable;
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threshold = (int) (newCapacity * loadFactor);
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}
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|
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/**
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* Copies all of the mappings from the specified map to this map
|
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* These mappings will replace any mappings that
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* this map had for any of the keys currently in the specified map.
|
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*
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* @param t mappings to be stored in this map.
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* @throws NullPointerException if the specified map is null.
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*/
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public final synchronized void putAll (Map t)
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{
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// Expand enough to hold t's elements without resizing.
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int n = t.size ();
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if (n == 0) return;
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if (n >= threshold)
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{
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n = (int) (n / loadFactor + 1);
|
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if (n > MAXIMUM_CAPACITY) n = MAXIMUM_CAPACITY;
|
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int capacity = table.length;
|
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while (capacity < n) capacity <<= 1;
|
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resize (capacity);
|
||||
}
|
||||
|
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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, null);
|
||||
return (e == null ? e : e.value);
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* Removes the mapping for this key from this map if present and value
|
||||
* equals the parameter value. If parameter value is null, behaves
|
||||
* exactly like <code>remove (Object key)</code>.
|
||||
*
|
||||
* @param key key whose mapping is to be removed from the map.
|
||||
* @param value value that is mapped to this key.
|
||||
* @return <tt>true</tt> if the entry was removed, or <tt>false</tt>
|
||||
* if there was no mapping for key or the key is not mapped to
|
||||
* the parameter value.
|
||||
*/
|
||||
public boolean remove (Object key, Object value)
|
||||
{
|
||||
Entry e = removeEntryForKey (key, value);
|
||||
return (e == null ? false : true);
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* Removes and returns the entry associated with the specified key and value
|
||||
* in the ConcurrentHashMap. If value is null, only matches the key.
|
||||
* Returns null if the ConcurrentHashMap contains no mapping for this key or
|
||||
* key is not mapped to the input value.
|
||||
*/
|
||||
private Entry removeEntryForKey (Object key, Object v)
|
||||
{
|
||||
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) &&
|
||||
(v == null || eq (v, e.value)))
|
||||
{
|
||||
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) &&
|
||||
(v == null || eq (v, e.value)))
|
||||
{
|
||||
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;
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* 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 ());
|
||||
}
|
||||
|
||||
|
||||
protected Object clone ()
|
||||
{
|
||||
// It is the callers responsibility to set the next field
|
||||
// correctly.
|
||||
return new Entry (hash, key, value, null);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
private abstract class HashIterator implements Iterator
|
||||
{
|
||||
final Entry[] table = ConcurrentHashMap.this.table;
|
||||
Entry next; // next entry to return
|
||||
int index; // current slot
|
||||
Entry current; // current entry
|
||||
|
||||
HashIterator ()
|
||||
{
|
||||
if (size == 0) return;
|
||||
Entry[] t = table;
|
||||
int i = t.length-1;
|
||||
Entry n = t[i];
|
||||
while (n == null && i > 0) n = t[--i];
|
||||
index = i;
|
||||
next = n;
|
||||
}
|
||||
|
||||
|
||||
public final boolean hasNext ()
|
||||
{
|
||||
return next != null;
|
||||
}
|
||||
|
||||
|
||||
final Entry nextEntry ()
|
||||
{
|
||||
Entry e = next;
|
||||
if (e == null) throw new NoSuchElementException ();
|
||||
|
||||
Entry n = e.next;
|
||||
Entry[] t = table;
|
||||
int i = index;
|
||||
while (n == null && i > 0) n = t[--i];
|
||||
index = i;
|
||||
next = n;
|
||||
return current = e;
|
||||
}
|
||||
|
||||
|
||||
public final void remove ()
|
||||
{
|
||||
if (current == null) throw new IllegalStateException ();
|
||||
Object k = current.key;
|
||||
current = null;
|
||||
ConcurrentHashMap.this.removeEntryForKey (k, null);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
private final class ValueIterator extends HashIterator
|
||||
{
|
||||
public Object next ()
|
||||
{
|
||||
return nextEntry ().value;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
private final class KeyIterator extends HashIterator
|
||||
{
|
||||
public Object next ()
|
||||
{
|
||||
return nextEntry ().getKey ();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
private final class EntryIterator extends HashIterator
|
||||
{
|
||||
public Object next ()
|
||||
{
|
||||
return nextEntry ();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
// 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 KeyIterator ();
|
||||
}
|
||||
|
||||
|
||||
public int size ()
|
||||
{
|
||||
return size;
|
||||
}
|
||||
|
||||
|
||||
public boolean contains (Object o)
|
||||
{
|
||||
return containsKey (o);
|
||||
}
|
||||
|
||||
|
||||
public boolean remove (Object o)
|
||||
{
|
||||
return ConcurrentHashMap.this.removeEntryForKey (o, null) != 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 ValueIterator ();
|
||||
}
|
||||
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 EntryIterator ();
|
||||
}
|
||||
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);
|
||||
|
||||
// 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 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);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user