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.BoundedMap; 029import org.apache.commons.collections4.CollectionUtils; 030import org.apache.commons.collections4.collection.UnmodifiableCollection; 031import org.apache.commons.collections4.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 * @param <K> the type of the keys in this map 055 * @param <V> the type of the values in this map 056 * @since 3.0 057 */ 058public class FixedSizeSortedMap<K, V> 059 extends AbstractSortedMapDecorator<K, V> 060 implements BoundedMap<K, V>, Serializable { 061 062 /** Serialization version */ 063 private static final long serialVersionUID = 3126019624511683653L; 064 065 /** 066 * Factory method to create a fixed size sorted map. 067 * 068 * @param <K> the key type 069 * @param <V> the value type 070 * @param map the map to decorate, must not be null 071 * @return a new fixed size sorted map 072 * @throws NullPointerException if map is null 073 * @since 4.0 074 */ 075 public static <K, V> FixedSizeSortedMap<K, V> fixedSizeSortedMap(final SortedMap<K, V> map) { 076 return new FixedSizeSortedMap<>(map); 077 } 078 079 //----------------------------------------------------------------------- 080 /** 081 * Constructor that wraps (not copies). 082 * 083 * @param map the map to decorate, must not be null 084 * @throws NullPointerException if map is null 085 */ 086 protected FixedSizeSortedMap(final SortedMap<K, V> map) { 087 super(map); 088 } 089 090 /** 091 * Gets the map being decorated. 092 * 093 * @return the decorated map 094 */ 095 protected SortedMap<K, V> getSortedMap() { 096 return (SortedMap<K, V>) map; 097 } 098 099 //----------------------------------------------------------------------- 100 /** 101 * Write the map out using a custom routine. 102 * 103 * @param out the output stream 104 * @throws IOException if an error occurs while writing to the stream 105 */ 106 private void writeObject(final ObjectOutputStream out) throws IOException { 107 out.defaultWriteObject(); 108 out.writeObject(map); 109 } 110 111 /** 112 * Read the map in using a custom routine. 113 * 114 * @param in the input stream 115 * @throws IOException if an error occurs while reading from the stream 116 * @throws ClassNotFoundException if an object read from the stream can not be loaded 117 */ 118 @SuppressWarnings("unchecked") // (1) should only fail if input stream is incorrect 119 private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException { 120 in.defaultReadObject(); 121 map = (Map<K, V>) in.readObject(); // (1) 122 } 123 124 //----------------------------------------------------------------------- 125 @Override 126 public V put(final K key, final V value) { 127 if (map.containsKey(key) == false) { 128 throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size"); 129 } 130 return map.put(key, value); 131 } 132 133 @Override 134 public void putAll(final Map<? extends K, ? extends V> mapToCopy) { 135 if (CollectionUtils.isSubCollection(mapToCopy.keySet(), keySet())) { 136 throw new IllegalArgumentException("Cannot put new key/value pair - Map is fixed size"); 137 } 138 map.putAll(mapToCopy); 139 } 140 141 @Override 142 public void clear() { 143 throw new UnsupportedOperationException("Map is fixed size"); 144 } 145 146 @Override 147 public V remove(final Object key) { 148 throw new UnsupportedOperationException("Map is fixed size"); 149 } 150 151 @Override 152 public Set<Map.Entry<K, V>> entrySet() { 153 return UnmodifiableSet.unmodifiableSet(map.entrySet()); 154 } 155 156 @Override 157 public Set<K> keySet() { 158 return UnmodifiableSet.unmodifiableSet(map.keySet()); 159 } 160 161 @Override 162 public Collection<V> values() { 163 return UnmodifiableCollection.unmodifiableCollection(map.values()); 164 } 165 166 //----------------------------------------------------------------------- 167 @Override 168 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 169 return new FixedSizeSortedMap<>(getSortedMap().subMap(fromKey, toKey)); 170 } 171 172 @Override 173 public SortedMap<K, V> headMap(final K toKey) { 174 return new FixedSizeSortedMap<>(getSortedMap().headMap(toKey)); 175 } 176 177 @Override 178 public SortedMap<K, V> tailMap(final K fromKey) { 179 return new FixedSizeSortedMap<>(getSortedMap().tailMap(fromKey)); 180 } 181 182 @Override 183 public boolean isFull() { 184 return true; 185 } 186 187 @Override 188 public int maxSize() { 189 return size(); 190 } 191 192}