ini/trakem2/utils/Lock.java

   1 /**
   2
   3 TrakEM2 plugin for ImageJ(C).
   4 Copyright (C) 2005, 2006 Albert Cardona and Rodney Douglas.
   5
   6 This program is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public License
   8 as published by the Free Software Foundation (http://www.gnu.org/licenses/gpl.txt )
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18
  19 You may contact Albert Cardona at acardona at ini.phys.ethz.ch
  20 Institute of Neuroinformatics, University of Zurich / ETH, Switzerland.
  21 **/
  22
  23 package ini.trakem2.utils;
  24
  25 /** For thread synchronization.
  26  * Both methods MUST ALWAYS be called from within a statement synchronizing on this object, such as:<br />
  27  *  <br />
  28  *  final Lock lock = new Lock();<br />
  29  *  synchronized (lock) {<br />
  30  *      lock.lock();<br />
  31  *      try {<br />
  32  *              ... (do whatever needs be synchronized on this lock) ...<br />
  33  *      } catch (Exception e) {<br />
  34  *              e.printStackTrace();<br />
  35  *      }<br />
  36  *      lock.unlock();<br />
  37  *  }<br />
  38  */
  39 public class Lock {
  40         protected boolean locked = false;
  41         protected boolean debug = false;
  42         static protected boolean debug_all = false;
  43         public final void lock() {
  44                 if (debug || debug_all) Utils.printCaller(this, 7);
  45                 while (locked) try { this.wait(); } catch (InterruptedException ie) {}
  46                 locked = true;
  47         }
  48         public final void unlock() {
  49                 if (debug || debug_all) Utils.printCaller(this, 7);
  50                 locked = false;
  51                 this.notifyAll();
  52         }
  53         public final void debug() {
  54                 debug = true;
  55         }
  56         static public final void debugAll() {
  57                 debug_all = true;
  58         }
  59 }