77 lines
3.2 KiB
Java
77 lines
3.2 KiB
Java
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/*
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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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import java.util.Comparator;
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/**
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* Represents an operation upon two operands of the same type, producing a result
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* of the same type as the operands. This is a specialization of
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* {@link BiFunction} for the case where the operands and the result are all of
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* the same type.
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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 #apply(Object, Object)}.
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*
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* @param <T> the type of the operands and result of the operator
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*
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* @see BiFunction
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* @see UnaryOperator
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* @since 1.8
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*/
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@FunctionalInterface
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public interface BinaryOperator<T> extends BiFunction<T,T,T> {
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/**
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* Returns a {@link BinaryOperator} which returns the lesser of two elements
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* according to the specified {@code Comparator}.
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*
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* @param <T> the type of the input arguments of the comparator
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* @param comparator a {@code Comparator} for comparing the two values
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* @return a {@code BinaryOperator} which returns the lesser of its operands,
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* according to the supplied {@code Comparator}
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* @throws NullPointerException if the argument is null
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*/
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public static <T> BinaryOperator<T> minBy(Comparator<? super T> comparator) {
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Objects.requireNonNull(comparator);
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return (a, b) -> comparator.compare(a, b) <= 0 ? a : b;
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}
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/**
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* Returns a {@link BinaryOperator} which returns the greater of two elements
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* according to the specified {@code Comparator}.
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*
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* @param <T> the type of the input arguments of the comparator
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* @param comparator a {@code Comparator} for comparing the two values
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* @return a {@code BinaryOperator} which returns the greater of its operands,
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* according to the supplied {@code Comparator}
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* @throws NullPointerException if the argument is null
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*/
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public static <T> BinaryOperator<T> maxBy(Comparator<? super T> comparator) {
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Objects.requireNonNull(comparator);
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return (a, b) -> comparator.compare(a, b) >= 0 ? a : b;
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}
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}
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