From: Nasir Khan <rubylearner@...>
Date: 2007-06-09T06:54:04+09:00
Subject: Re: Synchronized attr_accessor

There is no big picture.
The problem is simple - "create accessors for an instance variable
that access the variable under a lock".
Just as problem statement for "attr_accessor" could be - "create
accessors for instance variables"

- Nasir

PS: I understand that a synchronized access to hash is not the same as
synchronized access to hash values, but this problem is *not* about
it.


On Jun 8, 2:13 pm, MenTaLguY <men...@rydia.net> wrote:
> On Sat, 9 Jun 2007 04:55:24 +0900, Nasir Khan <rubylear...@gmail.com> wrote:
> > This is about having a instance variable always accessed under a lock,
> > if object state (instance variables) are accessed by many threads at
> > the same time for eg. a hash accessed by several threads for getting values but some
> > operation also adding deleting from the hash. You would want a
> > synchronized access to your hash in this case...
>
> Just because access to an instance variable is synchronized does not mean that access to the object it references is synchronized.  Retrieving a hash object via a synchronized accessor does not make it safe against concurrent modification.
>
> There are approaches which will work, but to know which ones to suggest, I will need to know more about the "bigger picture" that this code is part of.
>
> -mental