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Groups > comp.lang.java.programmer > #6769

Re: data shared between threads and synchronized on different objects

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On Tue, 2 Aug 2011, Marcin Rodzik wrote:

> I have a thread (the essential piece of its code can be found here:
> http://pastebin.com/KM8Yiqgs) which sends some objects ("tasks") over
> the network (in method tryToSendTask). Another thread submits objects
> to be sent by means of the first thread's method submit - namely, the
> "task" is put into queue.
>
> [...]
>
> What do you think?

I think you can make this a good bit simpler by using a BlockingQueue, 
such as a LinkedBlockingQueue. Any concurrency advantage a 
ConcurrentLinkedQueue might have is lost by the use of a synchronized 
method in your object.

With a BlockingQueue, the code looks more like:

public void submit(T t) {
     t.put(t);
}

public void run() {
     long timeout = Long.MAX_VALUE;
     while (goOn) {
         T t = taskSendingQueue.poll(timeout, TimeUnit.SECONDS);
         if (t != null) {
             sendTask(t);
             timeout = 0;
         }
         else {
             taskOutputStream.flush();
             timeout = Long.MAX_VALUE;
         }
     }
     completeCommunication();
}

I am mildly abusing poll here, by using extreme values of the timeout to 
effectively switch between blocking and non-blocking modes.

I don't know what this waitableClosing thing is, but i suspect you should 
combine it with goOn. A loop doesn't need more than one condition 
variable.

tom

-- 
a blood-spattered Canadarm flinging goat carcasses into the void

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Thread

data shared between threads and synchronized on different objects Marcin Rodzik <marteno_rodia@o2.pl> - 2011-08-02 07:53 -0700
  Re: data shared between threads and synchronized on different objects Tom Anderson <twic@urchin.earth.li> - 2011-08-02 22:41 +0100
    Re: data shared between threads and synchronized on different objects markspace <-@.> - 2011-08-02 15:02 -0700
      Re: data shared between threads and synchronized on different objects Tom Anderson <twic@urchin.earth.li> - 2011-08-03 14:29 +0100
        Re: data shared between threads and synchronized on different objects Patricia Shanahan <pats@acm.org> - 2011-08-03 08:34 -0700
          Re: data shared between threads and synchronized on different objects Tom Anderson <twic@urchin.earth.li> - 2011-08-03 18:27 +0100
            Re: data shared between threads and synchronized on different objects supercalifragilisticexpialadiamaticonormalizeringelimatisticantations <supercalifragilisticexpialadiamaticonormalizeringelimatisticantations@averylongandannoyingdomainname.com> - 2011-08-03 23:24 -0400

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