| /* |
| * Copyright 2009 Google Inc. |
| * |
| * 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 com.google.gwt.dev.util.collect; |
| |
| import java.io.Serializable; |
| import java.util.Collection; |
| import java.util.Map; |
| import java.util.Set; |
| |
| class IdentitySingletonMap<K, V> implements Map<K, V>, Serializable { |
| |
| private class IdentityEntry implements Entry<K, V> { |
| |
| @Override |
| public boolean equals(Object o) { |
| if (!(o instanceof Entry<?, ?>)) { |
| return false; |
| } |
| Entry<?, ?> entry = (Entry<?, ?>) o; |
| return key == entry.getKey() && value == entry.getValue(); |
| } |
| |
| public K getKey() { |
| return key; |
| } |
| |
| public V getValue() { |
| return value; |
| } |
| |
| @Override |
| public int hashCode() { |
| return System.identityHashCode(key) ^ System.identityHashCode(value); |
| } |
| |
| public V setValue(V value) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public String toString() { |
| return key + "=" + value; |
| } |
| } |
| |
| /** |
| * The key for the single entry. Default access to avoid synthetic accessors |
| * from inner classes. |
| */ |
| final K key; |
| |
| /** |
| * The value for the single entry. Default access to avoid synthetic accessors |
| * from inner classes. |
| */ |
| final V value; |
| |
| public IdentitySingletonMap(K key, V value) { |
| this.key = key; |
| this.value = value; |
| } |
| |
| public void clear() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean containsKey(Object k) { |
| return key == k; |
| } |
| |
| public boolean containsValue(Object v) { |
| return value == v; |
| } |
| |
| public Set<Entry<K, V>> entrySet() { |
| return Sets.<Entry<K, V>> create(new IdentityEntry()); |
| } |
| |
| @Override |
| @SuppressWarnings("unchecked") |
| public boolean equals(Object o) { |
| if (!(o instanceof Map)) { |
| return false; |
| } |
| Map<K, V> other = (Map<K, V>) o; |
| return entrySet().equals(other.entrySet()); |
| } |
| |
| public V get(Object k) { |
| return (key == k) ? value : null; |
| } |
| |
| @Override |
| public int hashCode() { |
| return System.identityHashCode(key) ^ System.identityHashCode(value); |
| } |
| |
| public boolean isEmpty() { |
| return false; |
| } |
| |
| public Set<K> keySet() { |
| return Sets.create(key); |
| } |
| |
| public V put(K key, V value) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public void putAll(Map<? extends K, ? extends V> m) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public V remove(Object key) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public int size() { |
| return 1; |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder buf = new StringBuilder(32 * size()); |
| buf.append('{'); |
| buf.append(key == this ? "(this Map)" : key).append('=').append( |
| value == this ? "(this Map)" : value); |
| buf.append('}'); |
| return buf.toString(); |
| } |
| |
| public Collection<V> values() { |
| return Sets.create(value); |
| } |
| } |