1 /* 2 * Copyright (C) 2007 Google Inc. 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 import com.google.common.base.Objects; 21 22 import java.util.Map.Entry; 23 24 import javax.annotation.Nullable; 25 26 /** 27 * Implementation of the {@code equals}, {@code hashCode}, and {@code toString} 28 * methods of {@code Entry}. 29 * 30 * @author Jared Levy 31 */ 32 @GwtCompatible 33 abstract class AbstractMapEntry<K, V> implements Entry<K, V> { 34 35 public abstract K getKey(); 36 37 public abstract V getValue(); 38 39 public V setValue(V value) { 40 throw new UnsupportedOperationException(); 41 } 42 43 @Override public boolean equals(@Nullable Object object) { 44 if (object instanceof Entry) { 45 Entry<?, ?> that = (Entry<?, ?>) object; 46 return Objects.equal(this.getKey(), that.getKey()) 47 && Objects.equal(this.getValue(), that.getValue()); 48 } 49 return false; 50 } 51 52 @Override public int hashCode() { 53 K k = getKey(); 54 V v = getValue(); 55 return ((k == null) ? 0 : k.hashCode()) ^ ((v == null) ? 0 : v.hashCode()); 56 } 57 58 /** 59 * Returns a string representation of the form <code>{key}={value}</code>. 60 */ 61 @Override public String toString() { 62 return getKey() + "=" + getValue(); 63 } 64 } 65
