1607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller/* 2607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 5607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * This code is free software; you can redistribute it and/or modify it 6607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * under the terms of the GNU General Public License version 2 only, as 7607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * published by the Free Software Foundation. Oracle designates this 8607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * particular file as subject to the "Classpath" exception as provided 9607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * by Oracle in the LICENSE file that accompanied this code. 10607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 11607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * This code is distributed in the hope that it will be useful, but WITHOUT 12607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * version 2 for more details (a copy is included in the LICENSE file that 15607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * accompanied this code). 16607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 17607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * You should have received a copy of the GNU General Public License version 18607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 2 along with this work; if not, write to the Free Software Foundation, 19607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 21607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * or visit www.oracle.com if you need additional information or have any 23607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * questions. 24607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller */ 25607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fullerpackage java.util.function; 26607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller 27607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fullerimport java.util.Objects; 28607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fullerimport java.util.Comparator; 29607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller 30607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller/** 31607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * Represents an operation upon two operands of the same type, producing a result 32607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * of the same type as the operands. This is a specialization of 33607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * {@link BiFunction} for the case where the operands and the result are all of 34607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * the same type. 35607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 36607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * <p>This is a <a href="package-summary.html">functional interface</a> 37607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * whose functional method is {@link #apply(Object, Object)}. 38607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 39607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @param <T> the type of the operands and result of the operator 40607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 41607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @see BiFunction 42607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @see UnaryOperator 43607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @since 1.8 44607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller */ 45607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller@FunctionalInterface 46607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fullerpublic interface BinaryOperator<T> extends BiFunction<T,T,T> { 47607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller /** 48607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * Returns a {@link BinaryOperator} which returns the lesser of two elements 49607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * according to the specified {@code Comparator}. 50607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 51607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @param <T> the type of the input arguments of the comparator 52607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @param comparator a {@code Comparator} for comparing the two values 53607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @return a {@code BinaryOperator} which returns the lesser of its operands, 54607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * according to the supplied {@code Comparator} 55607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @throws NullPointerException if the argument is null 56607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller */ 57607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller public static <T> BinaryOperator<T> minBy(Comparator<? super T> comparator) { 58607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller Objects.requireNonNull(comparator); 59607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller return (a, b) -> comparator.compare(a, b) <= 0 ? a : b; 60607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller } 61607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller 62607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller /** 63607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * Returns a {@link BinaryOperator} which returns the greater of two elements 64607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * according to the specified {@code Comparator}. 65607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * 66607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @param <T> the type of the input arguments of the comparator 67607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @param comparator a {@code Comparator} for comparing the two values 68607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @return a {@code BinaryOperator} which returns the greater of its operands, 69607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * according to the supplied {@code Comparator} 70607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller * @throws NullPointerException if the argument is null 71607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller */ 72607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller public static <T> BinaryOperator<T> maxBy(Comparator<? super T> comparator) { 73607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller Objects.requireNonNull(comparator); 74607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller return (a, b) -> comparator.compare(a, b) >= 0 ? a : b; 75607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller } 76607050af5a16c46ae53ff4d2c3f47b4ef694b559Neil Fuller} 77