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 */ 017package org.apache.commons.collections4.map; 018 019import java.io.IOException; 020import java.io.ObjectInputStream; 021import java.io.ObjectOutputStream; 022import java.io.Serializable; 023import java.util.Collection; 024import java.util.Map; 025import java.util.Set; 026import java.util.SortedMap; 027 028import org.apache.commons.collections4.set.UnmodifiableSet; 029import org.apache.commons.collections4.BoundedMap; 030import org.apache.commons.collections4.CollectionUtils; 031import org.apache.commons.collections4.collection.UnmodifiableCollection; 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 3.0 055 * @version $Id: FixedSizeSortedMap.html 972421 2015-11-14 20:00:04Z tn $ 056 */ 057public class FixedSizeSortedMap<K, V> 058 extends AbstractSortedMapDecorator<K, V> 059 implements BoundedMap<K, V>, Serializable { 060 061 /** Serialization version */ 062 private static final long serialVersionUID = 3126019624511683653L; 063 064 /** 065 * Factory method to create a fixed size sorted map. 066 * 067 * @param <K> the key type 068 * @param <V> the value type 069 * @param map the map to decorate, must not be null 070 * @return a new fixed size sorted map 071 * @throws IllegalArgumentException if map is null 072 * @since 4.0 073 */ 074 public static <K, V> FixedSizeSortedMap<K, V> fixedSizeSortedMap(final SortedMap<K, V> map) { 075 return new FixedSizeSortedMap<K, V>(map); 076 } 077 078 //----------------------------------------------------------------------- 079 /** 080 * Constructor that wraps (not copies). 081 * 082 * @param map the map to decorate, must not be null 083 * @throws IllegalArgumentException if map is null 084 */ 085 protected FixedSizeSortedMap(final SortedMap<K, V> map) { 086 super(map); 087 } 088 089 /** 090 * Gets the map being decorated. 091 * 092 * @return the decorated map 093 */ 094 protected SortedMap<K, V> getSortedMap() { 095 return (SortedMap<K, V>) map; 096 } 097 098 //----------------------------------------------------------------------- 099 /** 100 * Write the map out using a custom routine. 101 */ 102 private void writeObject(final ObjectOutputStream out) throws IOException { 103 out.defaultWriteObject(); 104 out.writeObject(map); 105 } 106 107 /** 108 * Read the map in using a custom routine. 109 */ 110 @SuppressWarnings("unchecked") // (1) should only fail if input stream is incorrect 111 private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException { 112 in.defaultReadObject(); 113 map = (Map<K, V>) in.readObject(); // (1) 114 } 115 116 //----------------------------------------------------------------------- 117 @Override 118 public V put(final K key, final V value) { 119 if (map.containsKey(key) == false) { 120 throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size"); 121 } 122 return map.put(key, value); 123 } 124 125 @Override 126 public void putAll(final Map<? extends K, ? extends V> mapToCopy) { 127 if (CollectionUtils.isSubCollection(mapToCopy.keySet(), keySet())) { 128 throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size"); 129 } 130 map.putAll(mapToCopy); 131 } 132 133 @Override 134 public void clear() { 135 throw new UnsupportedOperationException("Map is fixed size"); 136 } 137 138 @Override 139 public V remove(final Object key) { 140 throw new UnsupportedOperationException("Map is fixed size"); 141 } 142 143 @Override 144 public Set<Map.Entry<K, V>> entrySet() { 145 return UnmodifiableSet.unmodifiableSet(map.entrySet()); 146 } 147 148 @Override 149 public Set<K> keySet() { 150 return UnmodifiableSet.unmodifiableSet(map.keySet()); 151 } 152 153 @Override 154 public Collection<V> values() { 155 return UnmodifiableCollection.unmodifiableCollection(map.values()); 156 } 157 158 //----------------------------------------------------------------------- 159 @Override 160 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 161 return new FixedSizeSortedMap<K, V>(getSortedMap().subMap(fromKey, toKey)); 162 } 163 164 @Override 165 public SortedMap<K, V> headMap(final K toKey) { 166 return new FixedSizeSortedMap<K, V>(getSortedMap().headMap(toKey)); 167 } 168 169 @Override 170 public SortedMap<K, V> tailMap(final K fromKey) { 171 return new FixedSizeSortedMap<K, V>(getSortedMap().tailMap(fromKey)); 172 } 173 174 public boolean isFull() { 175 return true; 176 } 177 178 public int maxSize() { 179 return size(); 180 } 181 182}