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 */ 017package org.apache.commons.collections4.functors; 018 019import java.io.Serializable; 020import java.util.Objects; 021 022import org.apache.commons.collections4.Predicate; 023 024/** 025 * Predicate implementation that returns the opposite of the decorated predicate. 026 * 027 * @since 3.0 028 */ 029public final class NotPredicate<T> implements PredicateDecorator<T>, Serializable { 030 031 /** Serial version UID */ 032 private static final long serialVersionUID = -2654603322338049674L; 033 034 /** 035 * Factory to create the not predicate. 036 * 037 * @param <T> the type that the predicate queries 038 * @param predicate the predicate to decorate, not null 039 * @return the predicate 040 * @throws NullPointerException if the predicate is null 041 */ 042 public static <T> Predicate<T> notPredicate(final Predicate<? super T> predicate) { 043 return new NotPredicate<>(Objects.requireNonNull(predicate, "predicate")); 044 } 045 046 /** The predicate to decorate */ 047 private final Predicate<? super T> iPredicate; 048 049 /** 050 * Constructor that performs no validation. 051 * Use {@code notPredicate} if you want that. 052 * 053 * @param predicate the predicate to call after the null check 054 */ 055 public NotPredicate(final Predicate<? super T> predicate) { 056 iPredicate = predicate; 057 } 058 059 /** 060 * Evaluates the predicate returning the opposite to the stored predicate. 061 * 062 * @param object the input object 063 * @return true if predicate returns false 064 */ 065 @Override 066 public boolean evaluate(final T object) { 067 return !iPredicate.evaluate(object); 068 } 069 070 /** 071 * Gets the predicate being decorated. 072 * 073 * @return the predicate as the only element in an array 074 * @since 3.1 075 */ 076 @Override 077 @SuppressWarnings("unchecked") 078 public Predicate<? super T>[] getPredicates() { 079 return new Predicate[] {iPredicate}; 080 } 081 082}