| /* |
| * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package java.util.function; |
| |
| import java.util.Objects; |
| import java.util.Comparator; |
| |
| /** |
| * Represents an operation upon two operands of the same type, producing a result |
| * of the same type as the operands. This is a specialization of |
| * {@link BiFunction} for the case where the operands and the result are all of |
| * the same type. |
| * |
| * <p>This is a <a href="package-summary.html">functional interface</a> |
| * whose functional method is {@link #apply(Object, Object)}. |
| * |
| * @param <T> the type of the operands and result of the operator |
| * |
| * @see BiFunction |
| * @see UnaryOperator |
| * @since 1.8 |
| */ |
| @FunctionalInterface |
| public interface BinaryOperator<T> extends BiFunction<T,T,T> { |
| /** |
| * Returns a {@link BinaryOperator} which returns the lesser of two elements |
| * according to the specified {@code Comparator}. |
| * |
| * @param <T> the type of the input arguments of the comparator |
| * @param comparator a {@code Comparator} for comparing the two values |
| * @return a {@code BinaryOperator} which returns the lesser of its operands, |
| * according to the supplied {@code Comparator} |
| * @throws NullPointerException if the argument is null |
| */ |
| public static <T> BinaryOperator<T> minBy(Comparator<? super T> comparator) { |
| Objects.requireNonNull(comparator); |
| return (a, b) -> comparator.compare(a, b) <= 0 ? a : b; |
| } |
| |
| /** |
| * Returns a {@link BinaryOperator} which returns the greater of two elements |
| * according to the specified {@code Comparator}. |
| * |
| * @param <T> the type of the input arguments of the comparator |
| * @param comparator a {@code Comparator} for comparing the two values |
| * @return a {@code BinaryOperator} which returns the greater of its operands, |
| * according to the supplied {@code Comparator} |
| * @throws NullPointerException if the argument is null |
| */ |
| public static <T> BinaryOperator<T> maxBy(Comparator<? super T> comparator) { |
| Objects.requireNonNull(comparator); |
| return (a, b) -> comparator.compare(a, b) >= 0 ? a : b; |
| } |
| } |