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Sharing variables among classes?(easy question)

Gus Spain
Greenhorn

Joined: Sep 12, 2004
Posts: 17
Hello everybody,
i have a quite easy problem (i think) but i don�t know how to solve it!! (and it anoys me way too much!). I have some classes, which are able to create and destroy threads. The maximum number of threads should be 20, so these classes should share a variable holding the current number of threads, adding or substracting as they are created or destroyed, and in order to modify that value they should use a mutex.
And that�s my problem: how can i do so all the files, all the classes "see" the same value of the variable holding the number of threads, and use the same mutex in order to access to that value?
Any example would be of great help!
Thank you so much!!
Fisher Daniel
Ranch Hand

Joined: Sep 14, 2001
Posts: 582
Hi Gus Spain
I apologize that I dont understand what you mean with "mutex"..
About your problem, I think you can use class variable (static variable)..

Correct me if I am wrong
thanks
daniel
Gus Spain
Greenhorn

Joined: Sep 12, 2004
Posts: 17
Well, ��ll try to make myself clear:
"a.java" is a server that can create up to 20 threads. In order to not going over 20, there�s this variable "number_threads", so every time a thread is created, it goes up by one.
"b.java" is the code of the thread, and if there�s an exception, or if it ends smoothly, it has to take one from "number_threads".
"c.java" is another thread that cooperates with "b.java" with the same conditions for the thread to end.
So i need that all the three of them (a.java, b.java and c.java) access to number_thread to modify its value, using a mutex (MUtual-EXclusive code, like a semaphore). My question is, how can i do so the three files share the same variable, each of them seeing the new value very time is modified, and how can they share the semaphore (mutex)?
Dirk Schreckmann
Sheriff

Joined: Dec 10, 2001
Posts: 7023
Moving this to the Threads and Synchronization forum...
[ October 25, 2004: Message edited by: Dirk Schreckmann ]

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