1 /*
   2  * Copyright (c) 2012, 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 upon input objects. The operation may modify that object or
  31  * external state (other objects).
  32  *
  33  * <p>All block implementations are expected to: <ul>
  34  *
  35  * <li>When used for aggregate operations upon many elements blocks should not
  36  * assume that the {@code accept} operation will be called upon elements in any
  37  * specific order.</li>
  38  * </ul>
  39  *
  40  * @param <L> the type of input objects provided to {@code accept}.
  41  * @param <R> the type of input objects provided to {@code accept}.
  42  */
  43 public interface BiBlock<L, R> {
  44 
  45     /**
  46      * Performs operations upon the provided object which may modify that object
  47      * and/or external state.
  48      *
  49      * @param l an input object
  50      */
  51     void accept(L l, R r);
  52 
  53     /**
  54      * Returns a Block which performs in sequence the {@code apply} methods of
  55      * multiple Blocks. This Block's {@code apply} method is performed followed
  56      * by the {@code apply} method of the specified Block operation.
  57      *
  58      * @param other an additional Block which will be chained after this Block
  59      * @return a Block which performs in sequence the {@code apply} method of
  60      * this Block and the {@code apply} method of the specified Block operation
  61      */
  62     public default BiBlock<L, R> chain(BiBlock<? super L, ? super R> other) {
  63         Objects.requireNonNull(other);
  64 
  65         return (l, r) -> {
  66             accept(l, r);
  67             other.accept(l, r);
  68         };
  69     }
  70 }