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.functor.core; 018 019 import java.io.Serializable; 020 021 import org.apache.commons.functor.BinaryPredicate; 022 import org.apache.commons.functor.UnaryPredicate; 023 import org.apache.commons.functor.adapter.RightBoundPredicate; 024 025 /** 026 * {@link #test Tests} the reference (==) equality of its arguments. 027 * 028 * @param <L> the left argument type. 029 * @param <R> the right argument type. 030 * @version $Revision: 1160410 $ $Date: 2011-08-22 22:06:40 +0200 (Mon, 22 Aug 2011) $ 031 * @author Matt Benson 032 */ 033 public final class IsSame<L, R> implements BinaryPredicate<L, R>, Serializable { 034 // static attributes 035 // ------------------------------------------------------------------------ 036 /** 037 * Basic IsSame<Object, Object> instance. 038 */ 039 public static final IsSame<Object, Object> INSTANCE = IsSame.<Object, Object>instance(); 040 /** 041 * serialVersionUID declaration. 042 */ 043 private static final long serialVersionUID = 7024585699909734072L; 044 045 // constructor 046 // ------------------------------------------------------------------------ 047 /** 048 * Create a new IsSame. 049 */ 050 public IsSame() { 051 } 052 053 // predicate interface 054 // ------------------------------------------------------------------------ 055 /** 056 * {@inheritDoc} 057 */ 058 public boolean test(L left, R right) { 059 return left == right; 060 } 061 062 /** 063 * {@inheritDoc} 064 */ 065 public boolean equals(Object that) { 066 return that instanceof IsSame<?, ?>; 067 } 068 069 /** 070 * {@inheritDoc} 071 */ 072 public int hashCode() { 073 return "IsSame".hashCode(); 074 } 075 076 /** 077 * {@inheritDoc} 078 */ 079 public String toString() { 080 return "IsSame"; 081 } 082 083 // static methods 084 // ------------------------------------------------------------------------ 085 /** 086 * Get an IsSame instance. 087 * @param <L> the left argument type. 088 * @param <R> the right argument type. 089 * @return IsSame 090 */ 091 public static <L, R> IsSame<L, R> instance() { 092 return new IsSame<L, R>(); 093 } 094 095 /** 096 * Get an IsSame UnaryPredicate. 097 * @param <L> the left argument type. 098 * @param <R> the right argument type. 099 * @param object bound comparison object 100 * @return UnaryPredicate<L> 101 */ 102 public static <L, R> UnaryPredicate<L> as(R object) { 103 return new RightBoundPredicate<L>(new IsSame<L, R>(), object); 104 } 105 }