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}
027 * <code>true</code> iff its arguments are
028 * not {@link Object#equals equal} or both
029 * <code>null</code>.
030 * <p>
031 * This relation is symmetric but irreflexive
032 * and not transitive.
033 * </p>
034 * @param <L> the left argument type.
035 * @param <R> the right argument type.
036 * @version $Revision: 1160397 $ $Date: 2011-08-22 21:42:42 +0200 (Mon, 22 Aug 2011) $
037 * @author Rodney Waldhoff
038 */
039 public final class IsNotEqual<L, R> implements BinaryPredicate<L, R>, Serializable {
040 // static attributes
041 // ------------------------------------------------------------------------
042 /**
043 * Basic IsNotEqual<Object, Object> instance.
044 */
045 public static final IsNotEqual<Object, Object> INSTANCE = IsNotEqual.<Object, Object>instance();
046 /**
047 * serialVersionUID declaration.
048 */
049 private static final long serialVersionUID = -7303588338955281317L;
050
051 // constructor
052 // ------------------------------------------------------------------------
053 /**
054 * Create a new IsNotEqual.
055 */
056 public IsNotEqual() {
057 }
058
059 // predicate interface
060 // ------------------------------------------------------------------------
061 /**
062 * {@inheritDoc}
063 */
064 public boolean test(L left, R right) {
065 return (null == left ? null != right : !left.equals(right));
066 }
067
068 /**
069 * {@inheritDoc}
070 */
071 public boolean equals(Object that) {
072 return that instanceof IsNotEqual<?, ?>;
073 }
074
075 /**
076 * {@inheritDoc}
077 */
078 public int hashCode() {
079 return "IsNotEqual".hashCode();
080 }
081
082 /**
083 * {@inheritDoc}
084 */
085 public String toString() {
086 return "IsNotEqual";
087 }
088
089 // static methods
090 // ------------------------------------------------------------------------
091
092 /**
093 * Get an IsNotEqual instance.
094 * @param <L> the left argument type.
095 * @param <R> the right argument type.
096 * @return IsNotEqual<L, R>
097 */
098 public static <L, R> IsNotEqual<L, R> instance() {
099 return new IsNotEqual<L, R>();
100 }
101
102 /**
103 * Get an IsNotEqual UnaryPredicate.
104 * @param <L> the left argument type.
105 * @param <R> the right argument type.
106 * @param object bound comparison object
107 * @return UnaryPredicate<L>
108 */
109 public static <L, R> UnaryPredicate<L> to(R object) {
110 return new RightBoundPredicate<L>(new IsNotEqual<L, R>(), object);
111 }
112 }