001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.collections.map; 018 019 import java.io.IOException; 020 import java.io.ObjectInputStream; 021 import java.io.ObjectOutputStream; 022 import java.io.Serializable; 023 import java.util.Collection; 024 import java.util.Iterator; 025 import java.util.Map; 026 import java.util.Set; 027 import java.util.SortedMap; 028 029 import org.apache.commons.collections.BoundedMap; 030 import org.apache.commons.collections.collection.UnmodifiableCollection; 031 import org.apache.commons.collections.set.UnmodifiableSet; 032 033 /** 034 * Decorates another <code>SortedMap</code> to fix the size blocking add/remove. 035 * <p> 036 * Any action that would change the size of the map is disallowed. 037 * The put method is allowed to change the value associated with an existing 038 * key however. 039 * <p> 040 * If trying to remove or clear the map, an UnsupportedOperationException is 041 * thrown. If trying to put a new mapping into the map, an 042 * IllegalArgumentException is thrown. This is because the put method can 043 * succeed if the mapping's key already exists in the map, so the put method 044 * is not always unsupported. 045 * <p> 046 * <strong>Note that FixedSizeSortedMap is not synchronized and is not thread-safe.</strong> 047 * If you wish to use this map from multiple threads concurrently, you must use 048 * appropriate synchronization. The simplest approach is to wrap this map 049 * using {@link java.util.Collections#synchronizedSortedMap}. This class may throw 050 * exceptions when accessed by concurrent threads without synchronization. 051 * <p> 052 * This class is Serializable from Commons Collections 3.1. 053 * 054 * @since Commons Collections 3.0 055 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 056 * 057 * @author Stephen Colebourne 058 * @author Paul Jack 059 */ 060 public class FixedSizeSortedMap 061 extends AbstractSortedMapDecorator 062 implements SortedMap, BoundedMap, Serializable { 063 064 /** Serialization version */ 065 private static final long serialVersionUID = 3126019624511683653L; 066 067 /** 068 * Factory method to create a fixed size sorted map. 069 * 070 * @param map the map to decorate, must not be null 071 * @throws IllegalArgumentException if map is null 072 */ 073 public static SortedMap decorate(SortedMap map) { 074 return new FixedSizeSortedMap(map); 075 } 076 077 //----------------------------------------------------------------------- 078 /** 079 * Constructor that wraps (not copies). 080 * 081 * @param map the map to decorate, must not be null 082 * @throws IllegalArgumentException if map is null 083 */ 084 protected FixedSizeSortedMap(SortedMap map) { 085 super(map); 086 } 087 088 /** 089 * Gets the map being decorated. 090 * 091 * @return the decorated map 092 */ 093 protected SortedMap getSortedMap() { 094 return (SortedMap) map; 095 } 096 097 //----------------------------------------------------------------------- 098 /** 099 * Write the map out using a custom routine. 100 */ 101 private void writeObject(ObjectOutputStream out) throws IOException { 102 out.defaultWriteObject(); 103 out.writeObject(map); 104 } 105 106 /** 107 * Read the map in using a custom routine. 108 */ 109 private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { 110 in.defaultReadObject(); 111 map = (Map) in.readObject(); 112 } 113 114 //----------------------------------------------------------------------- 115 public Object put(Object key, Object value) { 116 if (map.containsKey(key) == false) { 117 throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size"); 118 } 119 return map.put(key, value); 120 } 121 122 public void putAll(Map mapToCopy) { 123 for (Iterator it = mapToCopy.keySet().iterator(); it.hasNext(); ) { 124 if (mapToCopy.containsKey(it.next()) == false) { 125 throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size"); 126 } 127 } 128 map.putAll(mapToCopy); 129 } 130 131 public void clear() { 132 throw new UnsupportedOperationException("Map is fixed size"); 133 } 134 135 public Object remove(Object key) { 136 throw new UnsupportedOperationException("Map is fixed size"); 137 } 138 139 public Set entrySet() { 140 Set set = map.entrySet(); 141 return UnmodifiableSet.decorate(set); 142 } 143 144 public Set keySet() { 145 Set set = map.keySet(); 146 return UnmodifiableSet.decorate(set); 147 } 148 149 public Collection values() { 150 Collection coll = map.values(); 151 return UnmodifiableCollection.decorate(coll); 152 } 153 154 //----------------------------------------------------------------------- 155 public SortedMap subMap(Object fromKey, Object toKey) { 156 SortedMap map = getSortedMap().subMap(fromKey, toKey); 157 return new FixedSizeSortedMap(map); 158 } 159 160 public SortedMap headMap(Object toKey) { 161 SortedMap map = getSortedMap().headMap(toKey); 162 return new FixedSizeSortedMap(map); 163 } 164 165 public SortedMap tailMap(Object fromKey) { 166 SortedMap map = getSortedMap().tailMap(fromKey); 167 return new FixedSizeSortedMap(map); 168 } 169 170 public boolean isFull() { 171 return true; 172 } 173 174 public int maxSize() { 175 return size(); 176 } 177 178 }