| // GenericsNote: Converted. |
| /* |
| * Copyright 2002-2004 The Apache Software Foundation |
| * |
| * 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 org.jivesoftware.smack.util.collections; |
| |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.Serializable; |
| |
| /** |
| * A <code>Map</code> implementation that allows mappings to be |
| * removed by the garbage collector. |
| * <p/> |
| * When you construct a <code>ReferenceMap</code>, you can specify what kind |
| * of references are used to store the map's keys and values. |
| * If non-hard references are used, then the garbage collector can remove |
| * mappings if a key or value becomes unreachable, or if the JVM's memory is |
| * running low. For information on how the different reference types behave, |
| * see {@link java.lang.ref.Reference}. |
| * <p/> |
| * Different types of references can be specified for keys and values. |
| * The keys can be configured to be weak but the values hard, |
| * in which case this class will behave like a |
| * <a href="http://java.sun.com/j2se/1.4/docs/api/java/util/WeakHashMap.html"> |
| * <code>WeakHashMap</code></a>. However, you can also specify hard keys and |
| * weak values, or any other combination. The default constructor uses |
| * hard keys and soft values, providing a memory-sensitive cache. |
| * <p/> |
| * This map is similar to ReferenceIdentityMap. |
| * It differs in that keys and values in this class are compared using <code>equals()</code>. |
| * <p/> |
| * This {@link java.util.Map} implementation does <i>not</i> allow null elements. |
| * Attempting to add a null key or value to the map will raise a <code>NullPointerException</code>. |
| * <p/> |
| * This implementation is not synchronized. |
| * You can use {@link java.util.Collections#synchronizedMap} to |
| * provide synchronized access to a <code>ReferenceMap</code>. |
| * Remember that synchronization will not stop the garbage collecter removing entries. |
| * <p/> |
| * All the available iterators can be reset back to the start by casting to |
| * <code>ResettableIterator</code> and calling <code>reset()</code>. |
| * <p/> |
| * NOTE: As from Commons Collections 3.1 this map extends <code>AbstractReferenceMap</code> |
| * (previously it extended AbstractMap). As a result, the implementation is now |
| * extensible and provides a <code>MapIterator</code>. |
| * |
| * @author Paul Jack |
| * @author Matt Hall, John Watkinson, Stephen Colebourne |
| * @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:32 $ |
| * @see java.lang.ref.Reference |
| * @since Commons Collections 3.0 (previously in main package v2.1) |
| */ |
| public class ReferenceMap <K,V> extends AbstractReferenceMap<K, V> implements Serializable { |
| |
| /** |
| * Serialization version |
| */ |
| private static final long serialVersionUID = 1555089888138299607L; |
| |
| /** |
| * Constructs a new <code>ReferenceMap</code> that will |
| * use hard references to keys and soft references to values. |
| */ |
| public ReferenceMap() { |
| super(HARD, SOFT, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, false); |
| } |
| |
| /** |
| * Constructs a new <code>ReferenceMap</code> that will |
| * use the specified types of references. |
| * |
| * @param keyType the type of reference to use for keys; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param valueType the type of reference to use for values; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| */ |
| public ReferenceMap(int keyType, int valueType) { |
| super(keyType, valueType, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, false); |
| } |
| |
| /** |
| * Constructs a new <code>ReferenceMap</code> that will |
| * use the specified types of references. |
| * |
| * @param keyType the type of reference to use for keys; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param valueType the type of reference to use for values; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param purgeValues should the value be automatically purged when the |
| * key is garbage collected |
| */ |
| public ReferenceMap(int keyType, int valueType, boolean purgeValues) { |
| super(keyType, valueType, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, purgeValues); |
| } |
| |
| /** |
| * Constructs a new <code>ReferenceMap</code> with the |
| * specified reference types, load factor and initial |
| * capacity. |
| * |
| * @param keyType the type of reference to use for keys; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param valueType the type of reference to use for values; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param capacity the initial capacity for the map |
| * @param loadFactor the load factor for the map |
| */ |
| public ReferenceMap(int keyType, int valueType, int capacity, float loadFactor) { |
| super(keyType, valueType, capacity, loadFactor, false); |
| } |
| |
| /** |
| * Constructs a new <code>ReferenceMap</code> with the |
| * specified reference types, load factor and initial |
| * capacity. |
| * |
| * @param keyType the type of reference to use for keys; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param valueType the type of reference to use for values; |
| * must be {@link #HARD}, {@link #SOFT}, {@link #WEAK} |
| * @param capacity the initial capacity for the map |
| * @param loadFactor the load factor for the map |
| * @param purgeValues should the value be automatically purged when the |
| * key is garbage collected |
| */ |
| public ReferenceMap(int keyType, int valueType, int capacity, float loadFactor, boolean purgeValues) { |
| super(keyType, valueType, capacity, loadFactor, purgeValues); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Write the map out using a custom routine. |
| */ |
| private void writeObject(ObjectOutputStream out) throws IOException { |
| out.defaultWriteObject(); |
| doWriteObject(out); |
| } |
| |
| /** |
| * Read the map in using a custom routine. |
| */ |
| private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { |
| in.defaultReadObject(); |
| doReadObject(in); |
| } |
| |
| } |