BiFunction.java revision 607050af5a16c46ae53ff4d2c3f47b4ef694b559
1/* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25package java.util.function; 26 27import java.util.Objects; 28 29/** 30 * Represents a function that accepts two arguments and produces a result. 31 * This is the two-arity specialization of {@link Function}. 32 * 33 * <p>This is a <a href="package-summary.html">functional interface</a> 34 * whose functional method is {@link #apply(Object, Object)}. 35 * 36 * @param <T> the type of the first argument to the function 37 * @param <U> the type of the second argument to the function 38 * @param <R> the type of the result of the function 39 * 40 * @see Function 41 * @since 1.8 42 * @hide 1.8 43 */ 44@FunctionalInterface 45public interface BiFunction<T, U, R> { 46 47 /** 48 * Applies this function to the given arguments. 49 * 50 * @param t the first function argument 51 * @param u the second function argument 52 * @return the function result 53 */ 54 R apply(T t, U u); 55 56 /** 57 * Returns a composed function that first applies this function to 58 * its input, and then applies the {@code after} function to the result. 59 * If evaluation of either function throws an exception, it is relayed to 60 * the caller of the composed function. 61 * 62 * @param <V> the type of output of the {@code after} function, and of the 63 * composed function 64 * @param after the function to apply after this function is applied 65 * @return a composed function that first applies this function and then 66 * applies the {@code after} function 67 * @throws NullPointerException if after is null 68 */ 69 default <V> BiFunction<T, U, V> andThen(Function<? super R, ? extends V> after) { 70 Objects.requireNonNull(after); 71 return (T t, U u) -> after.apply(apply(t, u)); 72 } 73} 74