Semaphors with timeouts

Hi,

I need a kind of Semaphore that waits only a predefined timeout, something like:
sem := Semaphore new.
gotSem := sem waitMaxTime: 45.

This methods returns true if a could enter the critical section. But if I'm blocked, I am only willing to wait for 45 seconds. If I cannot enter the critical section in this time, the method returns false and i can react on this timeout.

Has anybody seen such a behaviour in VisualWorks?

Greetings

Klasu Muelheims


Collogia AG
Ubierring 11
 
50678 Köln
Germany
+49 221 336080
http://www.collogia.de


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Klaus,

I would fork of a process that after a delay signals the semaphore.

HTH,
Adriaan.



--
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Check out the class Promise. That might be exactly what you are looking for.

Andre


Mülheims schrieb:

Mülheims wrote:

Not exactly, but you can get inspiration from TimedPromise that lives in
the parcel Protocols-Common.

You might even be able to use TimedPromise directly if you don't mind
your critical section running in a forked thread...


R
-

Llasu

Look at SocketAccessor>>handleAsyncConnect:timeout:.

You will see that it creates a delay and then grabs its
semaphore. The method then uses this semaphore as the one
to signal if the operation completes. Next it waits on
the delay.

Terry
 
===========================================================
Terry Raymond       Smalltalk Professional Debug Package
Crafted Smalltalk
80 Lazywood Ln.
Tiverton, RI  02878
(401) 624-4517      [hidden email]
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===========================================================

> Hi,

Hi Klasu,

Yes, I've seen such behaviour in VisualWorks.

The Delay implementation is based on a semaphore that can be triggered.

delay := Delay forSeconds: 15
.
semaphore := delay delaySemaphore "use this semaphore to signal your  
process has finished"
.
delay wait
.
delay inProgress
        ifTrue: [
                "the semaphore was signalled before the delay was finished"
        ]
        ifFalse: [
                "the semaphore was not signalled on time"
        ]

Greetings,

Arjen van Elteren



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Hi,

Thanks for the responses, due to my limited time for this "project" and the many different approaches to solve my problem, it will take some time to check out, what solution fits best for my problem.

Greetings

Klaus


Collogia AG
Ubierring 11
 
50678 Köln
Germany
+49 221 336080
http://www.collogia.de

-----Ursprüngliche Nachricht-----
Von: arjen van elteren [mailto:[hidden email]]
Gesendet: Montag, 4. September 2006 17:50
An: Mülheims, Klaus; vwnc-list
Betreff: Re: Semaphors with timeouts

> Hi,

Hi Klasu,

Yes, I've seen such behaviour in VisualWorks.

The Delay implementation is based on a semaphore that can be triggered.

delay := Delay forSeconds: 15
.
semaphore := delay delaySemaphore "use this semaphore to signal your  
process has finished"
.
delay wait
.
delay inProgress
        ifTrue: [
                "the semaphore was signalled before the delay was finished"
        ]
        ifFalse: [
                "the semaphore was not signalled on time"
        ]

Greetings,

Arjen van Elteren



--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/


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