1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.collections4.keyvalue; 18 19 import java.util.Map; 20 21 /** 22 * Abstract Pair class to assist with creating correct 23 * {@link java.util.Map.Entry Map.Entry} implementations. 24 * 25 * @param <K> the type of keys 26 * @param <V> the type of mapped values 27 * @since 3.0 28 */ 29 public abstract class AbstractMapEntry<K, V> extends AbstractKeyValue<K, V> implements Map.Entry<K, V> { 30 31 /** 32 * Constructs a new entry with the given key and given value. 33 * 34 * @param key the key for the entry, may be null 35 * @param value the value for the entry, may be null 36 */ 37 protected AbstractMapEntry(final K key, final V value) { 38 super(key, value); 39 } 40 41 // Map.Entry interface 42 //------------------------------------------------------------------------- 43 /** 44 * Sets the value stored in this <code>Map.Entry</code>. 45 * <p> 46 * This <code>Map.Entry</code> is not connected to a Map, so only the 47 * local data is changed. 48 * 49 * @param value the new value 50 * @return the previous value 51 */ 52 @Override 53 public V setValue(final V value) { // NOPMD 54 return super.setValue(value); 55 } 56 57 /** 58 * Compares this <code>Map.Entry</code> with another <code>Map.Entry</code>. 59 * <p> 60 * Implemented per API documentation of {@link java.util.Map.Entry#equals(Object)} 61 * 62 * @param obj the object to compare to 63 * @return true if equal key and value 64 */ 65 @Override 66 public boolean equals(final Object obj) { 67 if (obj == this) { 68 return true; 69 } 70 if (obj instanceof Map.Entry == false) { 71 return false; 72 } 73 final Map.Entry<?, ?> other = (Map.Entry<?, ?>) obj; 74 return 75 (getKey() == null ? other.getKey() == null : getKey().equals(other.getKey())) && 76 (getValue() == null ? other.getValue() == null : getValue().equals(other.getValue())); 77 } 78 79 /** 80 * Gets a hashCode compatible with the equals method. 81 * <p> 82 * Implemented per API documentation of {@link java.util.Map.Entry#hashCode()} 83 * 84 * @return a suitable hash code 85 */ 86 @Override 87 public int hashCode() { 88 return (getKey() == null ? 0 : getKey().hashCode()) ^ 89 (getValue() == null ? 0 : getValue().hashCode()); 90 } 91 92 }