Callback

Hello!  I want to create a callback that will call my method after,
say, 10 minutes.  How can I do it in squeak?

TIA.
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>>>>> "xyz" == xyz 42 <[hidden email]> writes:

xyz> Hello!  I want to create a callback that will call my method after,
xyz> say, 10 minutes.  How can I do it in squeak?

Open a Transcript and a workspace, and execute this in the Workspace:

  [(Delay forSeconds: 10) wait. Transcript show: 'done!'] fork.

Then go off and do something else for 10 seconds. :)

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Am 09.10.2008 um 15:54 schrieb xyz 42:

> Hello!  I want to create a callback that will call my method after,
> say, 10 minutes.  How can I do it in squeak?

[(Delay forDuration: 10 minutes) wait. self myMethod] fork

This forks off a background process, waits 10 minutes, then calls  
myMethod. Note that a lot of code will break when called from a  
background process, you will have to worry about synchronization.  
Especially you must not call UI code from the background (there are of  
course ways to allow that).

- Bert -


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On Oct 9, 2008, at 9:54 AM, xyz 42 wrote:

> Hello!  I want to create a callback that will call my method after,
> say, 10 minutes.  How can I do it in squeak?

You could try something like

        [10 minutes asDelay wait. self doSomething] fork

Breaking the above down,

        the square brackets indicate a block, the same kind of thing used in
        conditionals, select: messages, etc.

        "fork" tells the block to start running on a new thread, so  
statements after
        this one can execute without waiting the ten minutes.

        "10 minutes asDelay" creates a Delay object, and sending "wait" to it
        waits for the appropriate amount of time.

        Going further, "10 minutes" creates a Duration, and sending "asDelay"  
to
        it creates a Delay that is set up with the same amount of time as the  
Duration.

There are other ways to create Delays and Durations - check out the  
class side of Delay or Duration in a browser, as well as the  
"converting" category of methods for Number. (This is where the  
"minutes" message above comes from.)

Hope this helps,
Ben Schroeder

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Am 09.10.2008 um 16:07 schrieb Bert Freudenberg:


Seeing three very similar responses, here is another, safer way to do  
it for UI stuff. In a Morph subclass, you can say

        self addAlarm: #myMethod after: 10 minutes asMilliSeconds

This will call myMethod synchronously so you do not have to worry  
about background processes.

- Bert -


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On Oct 9, 2008, at 9:07 AM, Bert Freudenberg wrote:

>
> Am 09.10.2008 um 15:54 schrieb xyz 42:
>
>> Hello!  I want to create a callback that will call my method after,
>> say, 10 minutes.  How can I do it in squeak?
>
> [(Delay forDuration: 10 minutes) wait. self myMethod] fork
>
> This forks off a background process

Is there a distinction between processes and threads in Squeak?

> , waits 10 minutes, then calls myMethod. Note that a lot of code  
> will break when called from a background process, you will have to  
> worry about synchronization. Especially you must not call UI code  
> from the background (there are of course ways to allow that).


---
Mark Volkmann





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Am 09.10.2008 um 16:24 schrieb Mark Volkmann:


No. It's all "green threads" in modern parlor, but they are named  
"processes" for historic reasons.

- Bert -


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