001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.collections.functors; 018 019 import java.io.Serializable; 020 021 import org.apache.commons.collections.Predicate; 022 023 /** 024 * Predicate implementation that returns true if the input is the same object 025 * as the one stored in this predicate. 026 * 027 * @since Commons Collections 3.0 028 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 029 * 030 * @author Stephen Colebourne 031 */ 032 public final class IdentityPredicate implements Predicate, Serializable { 033 034 /** Serial version UID */ 035 private static final long serialVersionUID = -89901658494523293L; 036 037 038 /** The value to compare to */ 039 private final Object iValue; 040 041 /** 042 * Factory to create the identity predicate. 043 * 044 * @param object the object to compare to 045 * @return the predicate 046 * @throws IllegalArgumentException if the predicate is null 047 */ 048 public static Predicate getInstance(Object object) { 049 if (object == null) { 050 return NullPredicate.INSTANCE; 051 } 052 return new IdentityPredicate(object); 053 } 054 055 /** 056 * Constructor that performs no validation. 057 * Use <code>getInstance</code> if you want that. 058 * 059 * @param object the object to compare to 060 */ 061 public IdentityPredicate(Object object) { 062 super(); 063 iValue = object; 064 } 065 066 /** 067 * Evaluates the predicate returning true if the input object is identical to 068 * the stored object. 069 * 070 * @param object the input object 071 * @return true if input is the same object as the stored value 072 */ 073 public boolean evaluate(Object object) { 074 return (iValue == object); 075 } 076 077 /** 078 * Gets the value. 079 * 080 * @return the value 081 * @since Commons Collections 3.1 082 */ 083 public Object getValue() { 084 return iValue; 085 } 086 087 }