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Groups > comp.lang.java.programmer > #18924

Re: Interrupted exception chaining

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markspace schrieb:
>>    public boolean done; /* should be set by the thread that
>>                              notifies the lock */
>
>
> While I agree this works in some cases,

Just replace done by the <cond> you want to anyway check.
The main point is that you cannot go, since factoring
out the programming pattern works not:


    synchronized (c) {
       while (!<cond>)
          uninterruptableWait(c);
    }


But rather simply apply the programming pattern:

    try {
       synchronized (c) {
          while (!<cond>)
             c.wait();
       }
    } catch( InterruptedException ex ) {
       Thread.currentThread().interrupt();
    }

Or if you want to scare the hell out of your clients, use:

     public interface Predicate {
        public boolean _true(Object c);
     }

    public void uninterruptableWait(Object c, Predicate p) {
       try {
          synchronized (c) {
             while (!p._true(c))
                c.wait();
           }
       } catch( InterruptedException ex ) {
          Thread.currentThread().interrupt();
       }
    }

Then what you call "SpinLock", but what I would call
"OneTimeLock". Can be implemented as follows:

     public void waitDone() {
        uninterruptableWait(lock,new Predicate() {
             return done;
        });
     }

Of course you can turn a "OneTimeLock" into a "ManyTimeLock",
for example. You can reset the done inside the synchronized
of the waitDone(). The synchronized will assure that when
you leave the synchronized the done=false holds, since no
other thread will interfer while inside the synchronized
and after the wait():

   public void waitDone() {
       try {
          synchronized( lock ) {
             while( !done )
                lock.wait();
             done=false;
          }
       } catch( InterruptedException ex ) {
          Thread.currentThread().interrupt();
       }
   }

To abstract this pattern we would need:


     public interface Predicate {
        public boolean _true(Object c);
     }

     public interface Action{
        public boolean perform(Object c);
     }

    public void uninterruptableWait(Object c, Predicate p, Action a) {
       try {
          synchronized (c) {
             while (!p._true(c))
                c.wait();
             a.perform(c);
           }
       } catch( InterruptedException ex ) {
          Thread.currentThread().interrupt();
       }
    }

And one can then do:

     public void waitDone() {
        uninterruptableWait(lock,new Predicate() {
             return done;
        }, new Action() {
             done=false;
        });
     }

Eagerly avaiting JDK 7 lambdas...

Bye

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Interrupted exception chaining raphfrk@gmail.com - 2012-09-25 03:25 -0700
  Re: Interrupted exception chaining Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-25 08:56 -0400
  Re: Interrupted exception chaining markspace <-@.> - 2012-09-25 08:33 -0700
    Re: Interrupted exception chaining Ivan Ryan <ivan.ryan@gmail.com> - 2012-09-25 09:28 -0700
      Re: Interrupted exception chaining Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-25 13:12 -0400
      Re: Interrupted exception chaining markspace <-@.> - 2012-09-25 12:00 -0700
  Re: Interrupted exception chaining Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-09-25 09:22 -0700
    Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 22:26 +0200
      Re: Interrupted exception chaining markspace <-@.> - 2012-09-25 13:37 -0700
        Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 22:47 +0200
          Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 22:53 +0200
            Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 22:53 +0200
          Re: Interrupted exception chaining markspace <-@.> - 2012-09-25 14:08 -0700
            Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 23:23 +0200
              Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 23:24 +0200
              Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 23:32 +0200
            Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 23:42 +0200
              Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 23:48 +0200
              Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-25 23:55 +0200
                Re: Interrupted exception chaining markspace <-@.> - 2012-09-25 15:33 -0700
      Re: Interrupted exception chaining Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-25 21:43 -0400
  Re: Interrupted exception chaining Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2012-09-26 01:43 +0200
    Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-26 10:24 +0200
      Re: Interrupted exception chaining Jan Burse <janburse@fastmail.fm> - 2012-09-26 10:32 +0200
        Re: Interrupted exception chaining Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2012-09-26 16:26 +0200

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