1 //****************************************************************************** 2 // 3 // File: SharedSigned16BitIntegerBuf.java 4 // Package: edu.rit.mp.buf 5 // Unit: Class edu.rit.mp.buf.SharedSigned16BitIntegerBuf 6 // 7 // This Java source file is copyright (C) 2007 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 java.nio.ByteBuffer; 43 44 import edu.rit.mp.Buf; 45 import edu.rit.mp.Signed16BitIntegerBuf; 46 import edu.rit.pj.reduction.IntegerOp; 47 import edu.rit.pj.reduction.Op; 48 import edu.rit.pj.reduction.SharedInteger; 49 50 /** 51 * Class SharedSigned16BitIntegerBuf provides a buffer for a single signed 52 * 16-bit integer item sent or received using the Message Protocol (MP). While 53 * an instance of class SharedSigned16BitIntegerBuf may be constructed directly, 54 * normally you will use a factory method in class {@linkplain 55 * edu.rit.mp.Signed16BitIntegerBuf Signed16BitIntegerBuf}. See that class for 56 * further information. 57 * 58 * @author Alan Kaminsky 59 * @version 26-Oct-2007 60 */ 61 public class SharedSigned16BitIntegerBuf 62 extends Signed16BitIntegerBuf { 63 64 // Hidden data members. 65 SharedInteger myItem; 66 67 // Exported constructors. 68 /** 69 * Construct a new shared signed 16-bit integer buffer. 70 * 71 * @param item SharedInteger object that wraps the item. 72 */ 73 public SharedSigned16BitIntegerBuf(SharedInteger item) { 74 super(1); 75 myItem = item; 76 } 77 78 // Exported operations. 79 /** 80 * {@inheritDoc} 81 * 82 * Obtain the given item from this buffer. 83 * <P> 84 * The <code>get()</code> method must not block the calling thread; if it does, 85 * all message I/O in MP will be blocked. 86 */ 87 public int get(int i) { 88 return myItem.get(); 89 } 90 91 /** 92 * {@inheritDoc} 93 * 94 * Store the given item in this buffer. 95 * <P> 96 * The <code>put()</code> method must not block the calling thread; if it does, 97 * all message I/O in MP will be blocked. 98 */ 99 public void put(int i, 100 int item) { 101 myItem.set(item); 102 } 103 104 /** 105 * {@inheritDoc} 106 * 107 * Create a buffer for performing parallel reduction using the given binary 108 * operation. The results of the reduction are placed into this buffer. 109 * @exception ClassCastException (unchecked exception) Thrown if this 110 * buffer's element data type and the given binary operation's argument data 111 * type are not the same. 112 */ 113 public Buf getReductionBuf(Op op) { 114 return new SharedSigned16BitIntegerReductionBuf(myItem, (IntegerOp) op); 115 } 116 117 // Hidden operations. 118 /** 119 * {@inheritDoc} 120 * 121 * Send as many items as possible from this buffer to the given byte buffer. 122 * <P> 123 * The <code>sendItems()</code> method must not block the calling thread; if it 124 * does, all message I/O in MP will be blocked. 125 */ 126 protected int sendItems(int i, 127 ByteBuffer buffer) { 128 if (buffer.remaining() >= 2) { 129 buffer.putShort((short) myItem.get()); 130 return 1; 131 } else { 132 return 0; 133 } 134 } 135 136 /** 137 * {@inheritDoc} 138 * 139 * Receive as many items as possible from the given byte buffer to this 140 * buffer. 141 * <P> 142 * The <code>receiveItems()</code> method must not block the calling thread; if 143 * it does, all message I/O in MP will be blocked. 144 */ 145 protected int receiveItems(int i, 146 int num, 147 ByteBuffer buffer) { 148 if (num >= 1 && buffer.remaining() >= 2) { 149 myItem.set(buffer.getShort()); 150 return 1; 151 } else { 152 return 0; 153 } 154 } 155 156 }