1 /* 2 * Copyright (C) 2011 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.collect; 18 19 import com.google.common.annotations.GwtCompatible; 20 21 import java.util.Iterator; 22 import java.util.Map; 23 import java.util.Set; 24 25 /** 26 * Workaround for 27 * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6312706"> 28 * EnumMap bug</a>. If you want to pass an {@code EnumMap}, with the 29 * intention of using its {@code entrySet()} method, you should 30 * wrap the {@code EnumMap} in this class instead. 31 * 32 * <p>This class is not thread-safe even if the underlying map is. 33 * 34 * @author Dimitris Andreou 35 */ 36 @GwtCompatible 37 final class WellBehavedMap<K, V> extends ForwardingMap<K, V> { 38 private final Map<K, V> delegate; 39 private Set<Entry<K, V>> entrySet; 40 41 private WellBehavedMap(Map<K, V> delegate) { 42 this.delegate = delegate; 43 } 44 45 /** 46 * Wraps the given map into a {@code WellBehavedEntriesMap}, which 47 * intercepts its {@code entrySet()} method by taking the 48 * {@code Set<K> keySet()} and transforming it to 49 * {@code Set<Entry<K, V>>}. All other invocations are delegated as-is. 50 */ 51 static <K, V> WellBehavedMap<K, V> wrap(Map<K, V> delegate) { 52 return new WellBehavedMap<K, V>(delegate); 53 } 54 55 @Override protected Map<K, V> delegate() { 56 return delegate; 57 } 58 59 @Override public Set<Entry<K, V>> entrySet() { 60 Set<Entry<K, V>> es = entrySet; 61 if (es != null) { 62 return es; 63 } 64 return entrySet = new EntrySet(); 65 } 66 67 private final class EntrySet extends Maps.EntrySet<K, V> { 68 @Override 69 Map<K, V> map() { 70 return WellBehavedMap.this; 71 } 72 73 @Override 74 public Iterator<Entry<K, V>> iterator() { 75 return new TransformedIterator<K, Entry<K, V>>(keySet().iterator()) { 76 @Override 77 Entry<K, V> transform(final K key) { 78 return new AbstractMapEntry<K, V>() { 79 @Override 80 public K getKey() { 81 return key; 82 } 83 84 @Override 85 public V getValue() { 86 return get(key); 87 } 88 89 @Override 90 public V setValue(V value) { 91 return put(key, value); 92 } 93 }; 94 } 95 }; 96 } 97 } 98 } 99
