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5a95645a18
8011010: Spec j.u.f.Predicate doesn't specify NPEs thrown by the SE8's Reference Implementation Reviewed-by: briangoetz, dholmes, chegar
113 lines
4.1 KiB
Java
113 lines
4.1 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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* Determines if the input object matches some criteria.
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*
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* @param <T> the type of argument to {@code test}
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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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* Returns {@code true} if the input object matches some criteria.
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*
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* @param t the input object
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* @return {@code true} if the input object matches some criteria, otherwise
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* {@code false}
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*/
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boolean test(T t);
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/**
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* Returns a predicate which evaluates to {@code true} only if this
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* predicate and the provided predicate both evaluate to {@code true}. If
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* this predicate returns {@code false} then the remaining predicate is not
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* evaluated.
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*
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* <p>Any exceptions thrown by either {@code test} method are relayed
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* to the caller; if performing first operation throws an exception, the
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* second operation will not be performed.
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*
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* @param p a predicate which will be logically-ANDed with this predicate
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* @return a new predicate which returns {@code true} only if both
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* predicates return {@code true}
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* @throws NullPointerException if p is null
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*/
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default Predicate<T> and(Predicate<? super T> p) {
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Objects.requireNonNull(p);
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return (t) -> test(t) && p.test(t);
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}
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/**
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* Returns a predicate which negates the result of this predicate.
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*
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* @return a new predicate who's result is always the opposite 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 predicate which evaluates to {@code true} if either this
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* predicate or the provided predicate evaluates to {@code true}. If this
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* predicate returns {@code true} then the remaining predicate is not
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* evaluated.
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*
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* <p>Any exceptions thrown by either {@code test} method are relayed
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* to the caller; if performing first operation throws an exception, the
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* second operation will not be performed.
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*
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* @param p a predicate which will be logically-ORed with this predicate
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* @return a new predicate which returns {@code true} if either predicate
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* returns {@code true}
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* @throws NullPointerException if p is null
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*/
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default Predicate<T> or(Predicate<? super T> p) {
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Objects.requireNonNull(p);
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return (t) -> test(t) || p.test(t);
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}
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/**
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* Returns a predicate who's result matches
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* {@code Objects.equals(target, t)}.
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*
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* @param <T> the type of values evaluated by the predicate
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* @param target the target value to be compared for equality
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* @return a predicate who's result matches
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* {@code Objects.equals(target, t)}
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*/
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static <T> Predicate<T> isEqual(Object target) {
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return (null == target)
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? Objects::isNull
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: object -> target.equals(object);
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}
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}
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