1 /*
2  * Copyright (c) 2012, 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 two input arguments and returns no
31  * result.  This is the two-arity specialization of {@link Consumer}.
32  * Unlike most other functional interfaces, {@code BiConsumer} is expected
33  * to operate via side-effects.
34  *
35  * <p>This is a <a href="package-summary.html">functional interface</a>
36  * whose functional method is {@link #accept(Object, Object)}.
37  *
38  * @param <T> the type of the first argument to the operation
39  * @param <U> the type of the second argument to the operation
40  *
41  * @see Consumer
42  * @since 1.8
43  */
44 @FunctionalInterface
45 public interface BiConsumer<T, U> {
46 
47     /**
48      * Performs this operation on the given arguments.
49      *
50      * @param t the first input argument
51      * @param u the second input argument
52      */
accept(T t, U u)53     void accept(T t, U u);
54 
55     /**
56      * Returns a composed {@code BiConsumer} that performs, in sequence, this
57      * operation followed by the {@code after} operation. If performing either
58      * operation throws an exception, it is relayed to the caller of the
59      * composed operation.  If performing this operation throws an exception,
60      * the {@code after} operation will not be performed.
61      *
62      * @param after the operation to perform after this operation
63      * @return a composed {@code BiConsumer} that performs in sequence this
64      * operation followed by the {@code after} operation
65      * @throws NullPointerException if {@code after} is null
66      */
andThen(BiConsumer<? super T, ? super U> after)67     default BiConsumer<T, U> andThen(BiConsumer<? super T, ? super U> after) {
68         Objects.requireNonNull(after);
69 
70         return (l, r) -> {
71             accept(l, r);
72             after.accept(l, r);
73         };
74     }
75 }
76