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  * An operation which accepts a single input argument and returns no result.
  31  * Unlike most other functional interfaces, {@code Consumer} is expected to
  32  * operate via side-effects.
  33  *
  34  * @param <T> The type of input objects to {@code accept}
  35  *
  36  * @since 1.8
  37  */
  38 @FunctionalInterface
  39 public interface Consumer<T> {
  40 
  41     /**
  42      * Accept an input value.
  43      *
  44      * @param t the input object
  45      */
  46     void accept(T t);
  47 
  48     /**
  49      * Returns a Consumer which performs in sequence the {@code apply} methods
  50      * of multiple Consumers. This Consumer's {@code accept} method is performed
  51      * followed by the {@code accept} method of the specified Consumer operation.
  52      *
  53      * @param other an additional Consumer which will be chained after this
  54      * Consumer
  55      * @return a Consumer which performs in sequence the {@code accept} method
  56      * of this Consumer and the {@code accept} method of the specified Consumer
  57      * operation
  58      * @throws NullPointerException if other is null
  59      */
  60     default Consumer<T> chain(Consumer<? super T> other) {
  61         Objects.requireNonNull(other);
  62         return (T t) -> { accept(t); other.accept(t); };
  63     }
  64 }