141 lines
5.2 KiB
Java
141 lines
5.2 KiB
Java
/*
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* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.util.function;
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import java.util.Objects;
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/**
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* Represents a predicate (boolean-valued function) of one argument.
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*
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* <p>This is a <a href="package-summary.html">functional interface</a>
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* whose functional method is {@link #test(Object)}.
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*
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* @param <T> the type of the input to the predicate
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*
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* @since 1.8
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*/
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@FunctionalInterface
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public interface Predicate<T> {
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/**
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* Evaluates this predicate on the given argument.
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*
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* @param t the input argument
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* @return {@code true} if the input argument matches the predicate,
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* otherwise {@code false}
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*/
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boolean test(T t);
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/**
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* Returns a composed predicate that represents a short-circuiting logical
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* AND of this predicate and another. When evaluating the composed
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* predicate, if this predicate is {@code false}, then the {@code other}
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* predicate is not evaluated.
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*
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* <p>Any exceptions thrown during evaluation of either predicate are relayed
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* to the caller; if evaluation of this predicate throws an exception, the
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* {@code other} predicate will not be evaluated.
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*
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* @param other a predicate that will be logically-ANDed with this
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* predicate
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* @return a composed predicate that represents the short-circuiting logical
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* AND of this predicate and the {@code other} predicate
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* @throws NullPointerException if other is null
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*/
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default Predicate<T> and(Predicate<? super T> other) {
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Objects.requireNonNull(other);
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return (t) -> test(t) && other.test(t);
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}
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/**
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* Returns a predicate that represents the logical negation of this
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* predicate.
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*
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* @return a predicate that represents the logical negation of this
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* predicate
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*/
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default Predicate<T> negate() {
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return (t) -> !test(t);
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}
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/**
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* Returns a composed predicate that represents a short-circuiting logical
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* OR of this predicate and another. When evaluating the composed
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* predicate, if this predicate is {@code true}, then the {@code other}
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* predicate is not evaluated.
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*
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* <p>Any exceptions thrown during evaluation of either predicate are relayed
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* to the caller; if evaluation of this predicate throws an exception, the
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* {@code other} predicate will not be evaluated.
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*
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* @param other a predicate that will be logically-ORed with this
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* predicate
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* @return a composed predicate that represents the short-circuiting logical
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* OR of this predicate and the {@code other} predicate
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* @throws NullPointerException if other is null
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*/
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default Predicate<T> or(Predicate<? super T> other) {
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Objects.requireNonNull(other);
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return (t) -> test(t) || other.test(t);
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}
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/**
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* Returns a predicate that tests if two arguments are equal according
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* to {@link Objects#equals(Object, Object)}.
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*
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* @param <T> the type of arguments to the predicate
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* @param targetRef the object reference with which to compare for equality,
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* which may be {@code null}
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* @return a predicate that tests if two arguments are equal according
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* to {@link Objects#equals(Object, Object)}
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*/
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static <T> Predicate<T> isEqual(Object targetRef) {
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return (null == targetRef)
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? Objects::isNull
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: object -> targetRef.equals(object);
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}
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/**
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* Returns a predicate that is the negation of the supplied predicate.
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* This is accomplished by returning result of the calling
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* {@code target.negate()}.
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*
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* @param <T> the type of arguments to the specified predicate
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* @param target predicate to negate
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*
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* @return a predicate that negates the results of the supplied
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* predicate
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*
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* @throws NullPointerException if target is null
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*
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* @since 11
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*/
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@SuppressWarnings("unchecked")
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static <T> Predicate<T> not(Predicate<? super T> target) {
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Objects.requireNonNull(target);
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return (Predicate<T>)target.negate();
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}
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}
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