1 /* 2 * Copyright (c) 2010, 2012 Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package java.util.function; 26 27 import java.util.Objects; 28 29 /** 30 * Determines if the input object matches some criteria. 31 * 32 * @param <T> the type of input objects to {@code test} 33 * 34 * @since 1.8 35 */ 36 public interface Predicate<T> { 37 38 /** 39 * Returns {@code true} if the input object matches some criteria. 40 * 41 * @param t the input object 42 * @return {@code true} if the input object matches some criteria, otherwise 43 * {@code false} 44 */ 45 public boolean test(T t); 46 47 /** 48 * Returns a predicate which evaluates to {@code true} only if this 49 * predicate and the provided predicate both evaluate to {@code true}. If 50 * this predicate returns {@code false} then the remaining predicate is not 51 * evaluated. 52 * 53 * @return a new predicate which returns {@code true} only if both 54 * predicates return {@code true}. 55 */ 56 public default Predicate<T> and(Predicate<? super T> p) { 57 Objects.requireNonNull(p); 58 return (T t) -> test(t) && p.test(t); 59 } 60 61 /** 62 * Returns a predicate which negates the result of this predicate. 63 * 64 * @return a new predicate who's result is always the opposite of this 65 * predicate. 66 */ 67 public default Predicate<T> negate() { 68 return (T t) -> !test(t); 69 } 70 71 /** 72 * Returns a predicate which evaluates to {@code true} if either this 73 * predicate or the provided predicate evaluates to {@code true}. If this 74 * predicate returns {@code true} then the remaining predicate is not 75 * evaluated. 76 * 77 * @return a new predicate which returns {@code true} if either predicate 78 * returns {@code true}. 79 */ 80 public default Predicate<T> or(Predicate<? super T> p) { 81 Objects.requireNonNull(p); 82 return (T t) -> test(t) || p.test(t); 83 } 84 85 /** 86 * Returns a predicate that evaluates to {@code true} if all or none of the 87 * component predicates evaluate to {@code true}. 88 * 89 * @return a predicate that evaluates to {@code true} if all or none of the 90 * component predicates evaluate to {@code true} 91 */ 92 public default Predicate<T> xor(Predicate<? super T> p) { 93 Objects.requireNonNull(p); 94 return (T t) -> test(t) ^ p.test(t); 95 } 96 }