Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | // GenericsNote: Converted. |
| 2 | /* |
| 3 | * Copyright 2003-2004 The Apache Software Foundation |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * 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.jivesoftware.smack.util.collections; |
| 18 | |
| 19 | import java.util.Map; |
| 20 | |
| 21 | /** |
| 22 | * Abstract Pair class to assist with creating correct Map Entry implementations. |
| 23 | * |
| 24 | * @author James Strachan |
| 25 | * @author Michael A. Smith |
| 26 | * @author Neil O'Toole |
| 27 | * @author Matt Hall, John Watkinson, Stephen Colebourne |
| 28 | * @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:32 $ |
| 29 | * @since Commons Collections 3.0 |
| 30 | */ |
| 31 | public abstract class AbstractMapEntry <K,V> extends AbstractKeyValue<K, V> implements Map.Entry<K, V> { |
| 32 | |
| 33 | /** |
| 34 | * Constructs a new entry with the given key and given value. |
| 35 | * |
| 36 | * @param key the key for the entry, may be null |
| 37 | * @param value the value for the entry, may be null |
| 38 | */ |
| 39 | protected AbstractMapEntry(K key, V value) { |
| 40 | super(key, value); |
| 41 | } |
| 42 | |
| 43 | // Map.Entry interface |
| 44 | //------------------------------------------------------------------------- |
| 45 | /** |
| 46 | * Sets the value stored in this Map Entry. |
| 47 | * <p/> |
| 48 | * This Map Entry is not connected to a Map, so only the local data is changed. |
| 49 | * |
| 50 | * @param value the new value |
| 51 | * @return the previous value |
| 52 | */ |
| 53 | public V setValue(V value) { |
| 54 | V answer = this.value; |
| 55 | this.value = value; |
| 56 | return answer; |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * Compares this Map Entry with another Map Entry. |
| 61 | * <p/> |
| 62 | * Implemented per API documentation of {@link java.util.Map.Entry#equals(Object)} |
| 63 | * |
| 64 | * @param obj the object to compare to |
| 65 | * @return true if equal key and value |
| 66 | */ |
| 67 | public boolean equals(Object obj) { |
| 68 | if (obj == this) { |
| 69 | return true; |
| 70 | } |
| 71 | if (obj instanceof Map.Entry == false) { |
| 72 | return false; |
| 73 | } |
| 74 | Map.Entry other = (Map.Entry) obj; |
| 75 | return (getKey() == null ? other.getKey() == null : getKey().equals(other.getKey())) && (getValue() == null ? other.getValue() == null : getValue().equals(other.getValue())); |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * Gets a hashCode compatible with the equals method. |
| 80 | * <p/> |
| 81 | * Implemented per API documentation of {@link java.util.Map.Entry#hashCode()} |
| 82 | * |
| 83 | * @return a suitable hash code |
| 84 | */ |
| 85 | public int hashCode() { |
| 86 | return (getKey() == null ? 0 : getKey().hashCode()) ^ (getValue() == null ? 0 : getValue().hashCode()); |
| 87 | } |
| 88 | |
| 89 | } |