1 //******************************************************************************
2 //
3 // File: SharedObjectArrayReductionBuf.java
4 // Package: edu.rit.mp.buf
5 // Unit: Class edu.rit.mp.buf.SharedObjectArrayReductionBuf
6 //
7 // This Java source file is copyright (C) 2012 by Alan Kaminsky. All rights
8 // reserved. For further information, contact the author, Alan Kaminsky, at
9 // ark@cs.rit.edu.
10 //
11 // This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
12 // software; you can redistribute it and/or modify it under the terms of the GNU
13 // General Public License as published by the Free Software Foundation; either
14 // version 3 of the License, or (at your option) any later version.
15 //
16 // PJ is distributed in the hope that it will be useful, but WITHOUT ANY
17 // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
18 // A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19 //
20 // Linking this library statically or dynamically with other modules is making a
21 // combined work based on this library. Thus, the terms and conditions of the GNU
22 // General Public License cover the whole combination.
23 //
24 // As a special exception, the copyright holders of this library give you
25 // permission to link this library with independent modules to produce an
26 // executable, regardless of the license terms of these independent modules, and
27 // to copy and distribute the resulting executable under terms of your choice,
28 // provided that you also meet, for each linked independent module, the terms
29 // and conditions of the license of that module. An independent module is a module
30 // which is not derived from or based on this library. If you modify this library,
31 // you may extend this exception to your version of the library, but you are not
32 // obligated to do so. If you do not wish to do so, delete this exception
33 // statement from your version.
34 //
35 // A copy of the GNU General Public License is provided in the file gpl.txt. You
36 // may also obtain a copy of the GNU General Public License on the World Wide
37 // Web at http://www.gnu.org/licenses/gpl.html.
38 //
39 //******************************************************************************
40 package edu.rit.mp.buf;
41
42 import edu.rit.mp.Buf;
43 import edu.rit.pj.reduction.ObjectOp;
44 import edu.rit.pj.reduction.Op;
45 import edu.rit.pj.reduction.SharedObjectArray;
46 import edu.rit.util.Range;
47
48 /**
49 * Class SharedObjectArrayReductionBuf provides a reduction buffer for class
50 * {@linkplain SharedObjectArrayBuf}.
51 *
52 * @author Alan Kaminsky
53 * @version 01-Apr-2012
54 */
55 class SharedObjectArrayReductionBuf<T>
56 extends SharedObjectArrayBuf<T> {
57
58 // Hidden data members.
59 ObjectOp<T> myOp;
60 SharedObjectArrayBuf<T> myBuf;
61
62 // Exported constructors.
63 /**
64 * Construct a new shared object array reduction buffer.
65 *
66 * @param theArray Shared array.
67 * @param theRange Range of array elements to include in the buffer.
68 * @param op Binary operation.
69 * @param theBuf Underlying shared object array buffer.
70 * @exception NullPointerException (unchecked exception) Thrown if
71 * <code>op</code> is null.
72 */
73 public SharedObjectArrayReductionBuf(SharedObjectArray<T> theArray,
74 Range theRange,
75 ObjectOp<T> op,
76 SharedObjectArrayBuf<T> theBuf) {
77 super(theArray, theRange);
78 if (op == null) {
79 throw new NullPointerException("SharedObjectArrayReductionBuf(): op is null");
80 }
81 myOp = op;
82 myBuf = theBuf;
83 }
84
85 // Exported operations.
86 /**
87 * Store the given item in this buffer.
88 * <P>
89 * The <code>put()</code> method must not block the calling thread; if it does,
90 * all message I/O in MP will be blocked.
91 *
92 * @param i Item index in the range 0 .. <code>length()</code>-1.
93 * @param item Item to be stored at index <code>i</code>.
94 */
95 public void put(int i, T item) {
96 myArray.reduce(myArrayOffset + i * myStride, item, myOp);
97 reset();
98 myBuf.reset();
99 }
100
101 /**
102 * {@inheritDoc}
103 *
104 * Create a buffer for performing parallel reduction using the given binary
105 * operation. The results of the reduction are placed into this buffer.
106 * @exception ClassCastException (unchecked exception) Thrown if this
107 * buffer's element data type and the given binary operation's argument data
108 * type are not the same.
109 */
110 public Buf getReductionBuf(Op op) {
111 throw new UnsupportedOperationException();
112 }
113
114 }