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 */ 25 package java.util.function; 26 27 import java.util.Objects; 28 29 /** 30 * Represents an operation that accepts a single input argument and returns no 31 * result. Unlike most other functional interfaces, {@code Consumer} is expected 32 * to operate via side-effects. 33 * 34 * <p>This is a <a href="package-summary.html">functional interface</a> 35 * whose functional method is {@link #accept(Object)}. 36 * 37 * @param <T> the type of the input to the operation 38 * 39 * @since 1.8 40 */ 41 @FunctionalInterface 42 public interface Consumer<T> { 43 44 /** 45 * Performs this operation on the given argument. 46 * 47 * @param t the input argument 48 */ accept(T t)49 void accept(T t); 50 51 /** 52 * Returns a composed {@code Consumer} that performs, in sequence, this 53 * operation followed by the {@code after} operation. If performing either 54 * operation throws an exception, it is relayed to the caller of the 55 * composed operation. If performing this operation throws an exception, 56 * the {@code after} operation will not be performed. 57 * 58 * @param after the operation to perform after this operation 59 * @return a composed {@code Consumer} that performs in sequence this 60 * operation followed by the {@code after} operation 61 * @throws NullPointerException if {@code after} is null 62 */ andThen(Consumer<? super T> after)63 default Consumer<T> andThen(Consumer<? super T> after) { 64 Objects.requireNonNull(after); 65 return (T t) -> { accept(t); after.accept(t); }; 66 } 67 } 68