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Re: Question whether a problem with race conditions exists in this case

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On Wed, 14 Dec 2011, Saxo wrote:

> On Dec 14, 10:26 pm, Eric Sosman <esos...@ieee-dot-org.invalid> wrote:
>
>>>    private Object lock = new Object();
>>
>>      What does `lock' buy you?  Why not just synchronize on the
>> Node itself?
>
> The purpose is only to indicate that some more fine-gtrained locking
> would be used for the real thing instead of doing a synchronized(this)
> { ... } thing.

It's quite a common pattern. I'm always a bit dubious about using an 
public object (FSVO 'public') as the victim of a synchronized block; how 
do i know some random other bit of code in some other thread isn't going 
to try to lock the object at some point, and cause trouble? You wouldn't 
expose a field, would you? So why expose an object's lock? Essentially, i 
see an object's lock as a feature, like a method or a field; it should 
only be exposed to other classes after due consideration, and if it is, 
its proper use should be documented.

The locking analogue of a private field is an object like the above, 
created for the sole purpose of supplying a lock that is provably only 
accessible to code which can see the private details of the class.

I have coined the name 'lockguffin' for these objects, and i encourage you 
all to use it.

tom

-- 
And the future is certain, give us time to work it out

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Thread

Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 09:07 -0800
  Re: Question whether a problem with race conditions exists in this case Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-12-14 17:53 +0000
    Re: Question whether a problem with race conditions exists in this case Lew <lewbloch@gmail.com> - 2011-12-14 10:44 -0800
      Re: Question whether a problem with race conditions exists in this case Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-14 10:54 -0800
      Re: Question whether a problem with race conditions exists in this case Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-12-14 21:15 +0000
        Re: Question whether a problem with race conditions exists in this case Tom Anderson <twic@urchin.earth.li> - 2011-12-15 14:58 +0000
          Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-15 08:40 -0800
          Re: Question whether a problem with race conditions exists in this case Gene Wirchenko <genew@ocis.net> - 2011-12-15 11:55 -0800
            Re: Question whether a problem with race conditions exists in this case Tom Anderson <twic@urchin.earth.li> - 2011-12-16 14:06 +0000
              Re: Question whether a problem with race conditions exists in this case Gene Wirchenko <genew@ocis.net> - 2011-12-16 10:09 -0800
    Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 11:47 -0800
  Re: Question whether a problem with race conditions exists in this case Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-14 10:53 -0800
    Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 11:54 -0800
      Re: Question whether a problem with race conditions exists in this case Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-15 16:38 -0800
        Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-15 23:01 -0800
          Re: Question whether a problem with race conditions exists in this case Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-16 09:34 -0800
            Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-17 11:55 -0800
              Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-19 05:33 -0800
  Re: Question whether a problem with race conditions exists in this case Lew <lewbloch@gmail.com> - 2011-12-14 11:04 -0800
    Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 12:32 -0800
      Re: Question whether a problem with race conditions exists in this case markspace <-@.> - 2011-12-14 14:13 -0800
        Re: Question whether a problem with race conditions exists in this case Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-14 17:44 -0500
          Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 14:50 -0800
            Re: Question whether a problem with race conditions exists in this case markspace <-@.> - 2011-12-14 15:26 -0800
      Re: Question whether a problem with race conditions exists in this case Lew <lewbloch@gmail.com> - 2011-12-15 01:34 -0800
    Re: Question whether a problem with race conditions exists in this case Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-12-14 21:38 +0000
  Re: Question whether a problem with race conditions exists in this case Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-14 16:26 -0500
    Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 13:57 -0800
      Re: Question whether a problem with race conditions exists in this case Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-14 18:05 -0500
        Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 23:25 -0800
          Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 23:28 -0800
      Re: Question whether a problem with race conditions exists in this case Tom Anderson <twic@urchin.earth.li> - 2011-12-15 14:44 +0000
        Re: Question whether a problem with race conditions exists in this case Lew <lewbloch@gmail.com> - 2011-12-16 08:27 -0800
          Re: Question whether a problem with race conditions exists in this case Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-16 09:41 -0800
            Re: Question whether a problem with race conditions exists in this case Tom Anderson <twic@urchin.earth.li> - 2011-12-16 18:51 +0000
          Re: Question whether a problem with race conditions exists in this case Tom Anderson <twic@urchin.earth.li> - 2011-12-16 18:50 +0000
    Re: Question whether a problem with race conditions exists in this case Saxo <saxo123@gmx.de> - 2011-12-14 14:13 -0800
      Re: Question whether a problem with race conditions exists in this case Lew <lewbloch@gmail.com> - 2011-12-14 16:55 -0800

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