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.functor.core.composite; 18 19 import java.io.Serializable; 20 21 import org.apache.commons.functor.BinaryPredicate; 22 23 /** 24 * {@link #test Tests} to the logical inverse 25 * of some other predicate. 26 * <p> 27 * Note that although this class implements 28 * {@link Serializable}, a given instance will 29 * only be truly <code>Serializable</code> if the 30 * underlying functor is. Attempts to serialize 31 * an instance whose delegate is not 32 * <code>Serializable</code> will result in an exception. 33 * </p> 34 * @version $Revision: 1156320 $ $Date: 2011-08-10 21:14:50 +0200 (Wed, 10 Aug 2011) $ 35 * @author Rodney Waldhoff 36 */ 37 public final class BinaryNot<L, R> implements BinaryPredicate<L, R>, Serializable { 38 /** 39 * serialVersionUID declaration. 40 */ 41 private static final long serialVersionUID = -3488974286912054737L; 42 // attributes 43 // ------------------------------------------------------------------------ 44 private final BinaryPredicate<? super L, ? super R> predicate; 45 46 // constructor 47 // ------------------------------------------------------------------------ 48 /** 49 * Create a new BinaryNot. 50 * @param predicate BinaryPredicate to negate 51 */ 52 public BinaryNot(BinaryPredicate<? super L, ? super R> predicate) { 53 if (predicate == null) { 54 throw new IllegalArgumentException("BinaryPredicate argument was null"); 55 } 56 this.predicate = predicate; 57 } 58 59 // predicate interface 60 // ------------------------------------------------------------------------ 61 /** 62 * {@inheritDoc} 63 */ 64 public boolean test(L left, R right) { 65 return !(predicate.test(left, right)); 66 } 67 68 /** 69 * {@inheritDoc} 70 */ 71 public boolean equals(Object that) { 72 return that == this || (that instanceof BinaryNot<?, ?> && equals((BinaryNot<?, ?>) that)); 73 } 74 75 /** 76 * Learn whether another BinaryNot is equal to this. 77 * @param that BinaryNot to test 78 * @return boolean 79 */ 80 public boolean equals(BinaryNot<?, ?> that) { 81 return null != that && (null == predicate ? null == that.predicate : predicate.equals(that.predicate)); 82 } 83 84 /** 85 * {@inheritDoc} 86 */ 87 public int hashCode() { 88 int hash = "BinaryNot".hashCode(); 89 if (null != predicate) { 90 hash ^= predicate.hashCode(); 91 } 92 return hash; 93 } 94 95 /** 96 * {@inheritDoc} 97 */ 98 public String toString() { 99 return "BinaryNot<" + predicate + ">"; 100 } 101 102 // static 103 // ------------------------------------------------------------------------ 104 /** 105 * Negate a BinaryPredicate. 106 * @param that BinaryPredicate to negate 107 * @return BinaryPredicate 108 */ 109 public static <L, R> BinaryPredicate<L, R> not(BinaryPredicate<? super L, ? super R> that) { 110 return null == that ? null : new BinaryNot<L, R>(that); 111 } 112 113 }