In <[EMAIL PROTECTED]>, Chris Ashurst
wrote:
> Hi, I'm coming in from a despised Java background, and I'm having some
> trouble wrapping my head around sharing an object between multiple
> instances of a single class (in simpler terms, I would say imagine a
> simple chat server that has to share a list of connected users to each
> instance of a connected user).
>
> Usually, I would have a synchronized list instantiated inside each
> instance of a client class, which would do the trick, but since there's
> no synchronization in Python, I'm stuck staring at little tests
> involving a standalone non-threaded class instance that holds the list
> of users, and each connected user being passed this instance to be
> "synchronized".
There's no ``synchronized`` keyword, but of course you can synchronize
methods. You have to attach an `threading.RLock` to the objects you want
to synchronize on and use its `aquire()` and `release()` methods in places
where you used ``synchronized (someObject) { ... }`` in Java.
synchronized foo() { /* code */ }
is the same as
foo() {
synchronized (this) { /* code */ }
}
in Java. And that's basically:
def foo(self):
self.lock.aquire()
# code
self.lock.release()
You may want to make sure the lock will be released in case of an
exception:
def foo(self):
self.lock.aquire()
try:
pass # code
finally:
self.lock.release()
Ciao,
Marc 'BlackJack' Rintsch
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