1 //******************************************************************************
2 //
3 // File: ObjectArrayReductionBuf_1.java
4 // Package: edu.rit.mp.buf
5 // Unit: Class edu.rit.mp.buf.ObjectArrayReductionBuf_1
6 //
7 // This Java source file is copyright (C) 2009 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.mp.ObjectBuf;
44 import edu.rit.pj.reduction.ObjectOp;
45 import edu.rit.pj.reduction.Op;
46 import edu.rit.pj.reduction.ReduceArrays;
47 import edu.rit.util.Range;
48
49 /**
50 * Class ObjectArrayReductionBuf_1 provides a reduction buffer for class
51 * {@linkplain ObjectArrayBuf_1}.
52 *
53 * @param <T> Data type of the objects in the buffer.
54 *
55 * @author Alan Kaminsky
56 * @version 23-Mar-2009
57 */
58 @SuppressWarnings("unchecked")
59 class ObjectArrayReductionBuf_1<T>
60 extends ObjectArrayBuf_1<T> {
61
62 // Hidden data members.
63 ObjectOp<T> myOp;
64 ObjectArrayBuf<T> myBuf;
65
66 // Exported constructors.
67 /**
68 * Construct a new object array reduction buffer.
69 *
70 * @param theArray Array.
71 * @param theRange Range of array elements to include in the buffer. The
72 * stride is assumed to be 1.
73 * @param op Binary operation.
74 * @param theBuf Underlying object array buffer.
75 * @exception NullPointerException (unchecked exception) Thrown if
76 * <code>op</code> is null.
77 */
78 public ObjectArrayReductionBuf_1(T[] theArray,
79 Range theRange,
80 ObjectOp<T> op,
81 ObjectArrayBuf<T> theBuf) {
82 super(theArray, theRange);
83 if (op == null) {
84 throw new NullPointerException("ObjectArrayReductionBuf_1(): op is null");
85 }
86 myOp = op;
87 myBuf = theBuf;
88 }
89
90 // Exported operations.
91 /**
92 * Store the given item in this buffer.
93 * <P>
94 * The <code>put()</code> method must not block the calling thread; if it does,
95 * all message I/O in MP will be blocked.
96 *
97 * @param i Item index in the range 0 .. <code>length()</code>-1.
98 * @param item Item to be stored at index <code>i</code>.
99 */
100 public void put(int i,
101 T item) {
102 int off = myArrayOffset + i;
103 myArray[off] = myOp.op(myArray[off], item);
104 reset();
105 myBuf.reset();
106 }
107
108 /**
109 * {@inheritDoc}
110 *
111 * Copy items from the given buffer to this buffer. The number of items
112 * copied is this buffer's length or <code>theSrc</code>'s length, whichever is
113 * smaller. If <code>theSrc</code> is this buffer, the <code>copy()</code> method
114 * does nothing.
115 * @exception ClassCastException (unchecked exception) Thrown if
116 * <code>theSrc</code>'s item data type is not the same as this buffer's item
117 * data type.
118 */
119 public void copy(Buf theSrc) {
120 if (theSrc == this) {
121 } else if (theSrc instanceof ObjectArrayBuf) {
122 ObjectArrayBuf<T> src = (ObjectArrayBuf<T>) theSrc;
123 ReduceArrays.reduce(src.myArray, src.myRange, this.myArray, this.myRange, myOp);
124 reset();
125 myBuf.reset();
126 } else {
127 ObjectBuf.defaultCopy((ObjectBuf<T>) theSrc, this);
128 reset();
129 myBuf.reset();
130 }
131 }
132
133 /**
134 * {@inheritDoc}
135 *
136 * Create a buffer for performing parallel reduction using the given binary
137 * operation. The results of the reduction are placed into this buffer.
138 * @exception ClassCastException (unchecked exception) Thrown if this
139 * buffer's element data type and the given binary operation's argument data
140 * type are not the same.
141 */
142 public Buf getReductionBuf(Op op) {
143 throw new UnsupportedOperationException();
144 }
145
146 }