1 /*
  2  * Copyright (c) 2002, 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 
 26 package sun.nio.ch;
 27 

 28 
 29 // Special-purpose data structure for sets of native threads
 30 
 31 
 32 class NativeThreadSet {
 33 
 34     private long[] elts;
 35     private int used = 0;
 36     private boolean waitingToEmpty;
 37 
 38     NativeThreadSet(int n) {
 39         elts = new long[n];
 40     }
 41 
 42     // Adds the current native thread to this set, returning its index so that
 43     // it can efficiently be removed later.
 44     //



 45     int add() {
 46         long th = NativeThread.current();
 47         // 0 and -1 are treated as placeholders, not real thread handles
 48         if (th == 0)
 49             th = -1;
 50         synchronized (this) {
 51             int start = 0;
 52             if (used >= elts.length) {
 53                 int on = elts.length;
 54                 int nn = on * 2;
 55                 long[] nelts = new long[nn];
 56                 System.arraycopy(elts, 0, nelts, 0, on);
 57                 elts = nelts;
 58                 start = on;
 59             }
 60             for (int i = start; i < elts.length; i++) {
 61                 if (elts[i] == 0) {
 62                     elts[i] = th;
 63                     used++;

 64                     return i;
 65                 }
 66             }
 67             assert false;
 68             return -1;
 69         }

 70     }
 71 
 72     // Removes the thread at the given index.
 73     //

 74     void remove(int i) {
 75         synchronized (this) {


 76             elts[i] = 0;
 77             used--;
 78             if (used == 0 && waitingToEmpty)
 79                 notifyAll();
 80         }
 81     }
 82 
 83     // Signals all threads in this set.
 84     //
 85     synchronized void signalAndWait() {
 86         boolean interrupted = false;
 87         while (used > 0) {
 88             int u = used;
 89             int n = elts.length;
 90             for (int i = 0; i < n; i++) {
 91                 long th = elts[i];
 92                 if (th == 0)
 93                     continue;
 94                 if (th != -1)
 95                     NativeThread.signal(th);
 96                 if (--u == 0)
 97                     break;
 98             }
 99             waitingToEmpty = true;
100             try {
101                 wait(50);
102             } catch (InterruptedException e) {
103                 interrupted = true;
104             } finally {
105                 waitingToEmpty = false;
106             }
107         }
108         if (interrupted)
109             Thread.currentThread().interrupt();
110     }
111 }
--- EOF ---