[jboss-cvs] jmx/src/main/org/jboss/mx/util SchedulableRunnable.java

[Scott M S. <st...@us...>]

  User: starksm 
  Date: 04/12/29 21:54:02

  Modified:    src/main/org/jboss/mx/util Tag: Branch_4_0
                        SchedulableRunnable.java
  Log:
  Change the nextRun instance variable to a SynchronizedLong and remove the synchronization on the getNextRun() accessor to avoid deadlock when a scheduler is waiting on runnables and a runnable is trying to null out its scheduler due to a monitor being stopped. An example stack trace for this scenario is:

  

  Thread "Thread-0"@793 in group "main" status: MONITOR

  waitOutstanding():186, org.jboss.mx.util.RunnableScheduler

  run():93, org.jboss.mx.util.RunnableScheduler

  run():479, java.lang.Thread

  

  Thread "main"@1 in group "main" status: MONITOR

  setScheduler():126, org.jboss.mx.util.SchedulableRunnable

  stop():208, javax.management.monitor.StringMonitor

  ...

  stopMonitorService():399, org.jboss.test.jbossmx.compliance.monitor.BasicTestCase

  testStringBothNotification():235, org.jboss.test.jbossmx.compliance.monitor.BasicTestCase
  
  Revision  Changes    Path
  No                   revision
  
  
  No                   revision
  
  
  1.3.6.1   +7 -7      jmx/src/main/org/jboss/mx/util/SchedulableRunnable.java
  
  Index: SchedulableRunnable.java
  ===================================================================
  RCS file: /cvsroot/jboss/jmx/src/main/org/jboss/mx/util/SchedulableRunnable.java,v
  retrieving revision 1.3
  retrieving revision 1.3.6.1
  diff -u -r1.3 -r1.3.6.1
  --- SchedulableRunnable.java	26 Feb 2004 22:40:28 -0000	1.3
  +++ SchedulableRunnable.java	30 Dec 2004 05:54:02 -0000	1.3.6.1
  @@ -6,10 +6,9 @@
    */
   package org.jboss.mx.util;
   
  +import EDU.oswego.cs.dl.util.concurrent.SynchronizedLong;
   import org.jboss.logging.Logger;
   
  -import javax.management.timer.Timer;
  -
   /**
    * A schedulable runnable.<p>
    *
  @@ -22,7 +21,8 @@
    * @see RunnableScheduler
    *
    * @author  <a href="mailto:Adrian.Brock@HappeningTimes.com">Adrian Brock</a>.
  - * @version $Revision: 1.3 $
  + * @author Sco...@jb...
  + * @version $Revision: 1.3.6.1 $
    */
   public abstract class SchedulableRunnable
      implements Comparable, Runnable
  @@ -40,7 +40,7 @@
      /**
       * The next run timestamp
       */
  -   private long nextRun;
  +   private SynchronizedLong nextRun = new SynchronizedLong(0);
   
      /**
       * The current scheduler
  @@ -83,7 +83,7 @@
       */
      public long getNextRun()
      {
  -      return nextRun;
  +      return nextRun.get();
      }
   
      /**
  @@ -101,7 +101,7 @@
            scheduler.remove(this);
   
         // Set the new run time
  -      this.nextRun = nextRun;
  +      this.nextRun.set(nextRun);
   
         // If we are not running, add it to the scheduler otherwise
         // remember we want adding back
  @@ -185,7 +185,7 @@
      public int compareTo(Object o)
      {
          SchedulableRunnable other = (SchedulableRunnable) o;
  -       long temp = this.nextRun - other.nextRun;
  +       long temp = this.nextRun.get() - other.nextRun.get();
          if (temp < 0)
             return -1;
          if (temp > 0)