Re: [Jscheme-user] synchronized?

[Timothy H. <tim...@ma...>]

If you are going to start working with Threads and JScheme you might 
want to
be careful when working with Swing GUIs. Swing is not thread safe so it 
is a
good idea to execute any GUI manipulations in the AWT event queue thread.
This is done by using
>   (javax.swing.SwingUtilities.invokeAndWait (lambda() ...code to be 
> executed...))
> or
>   (javax.swing.SwingUtilities.invokeLater (lambda() ...code to be 
> executed...))
They both add the code to the event Queue as a runnable, this should 
only be done
from calls that are forked off of the main thread....

I usually also wrap the code in a tryCatch so as to catch any errors 
that might occur.
Otherwise the errors cause the thread to halt but are otherwise not 
observable:

> (define(invokeAndWait F)
>      (javax.swing.SwingUtilities.invokeAndWait (lambda()
>          (tryCatch
>              (F)
>              (lambda(e) (printdebug 'error {ERROR in invokeAndWait: 
> [F], [e]\n})))
>      ))
>   )
> ;; where printdebug is the  error printing procedure for your 
> application....
>


Have fun,
and be careful out there!
---Tim---


On Wednesday, March 5, 2003, at 03:46 PM, Geoffrey Knauth wrote:

> Thanks Tim!  Just what the doctor ordered.  --Geoffrey
>
> On Wednesday, March 5, 2003, at 03:24 PM, Timothy Hickey wrote:
>
>> (synchronize X F)
>> synchronizes the current thread on object X and blocks until it gets 
>> the
>> lock on X, at which time it calls (F X)
>>
>> e.g.
>> (synchronize x .wait) gets a lock on x and then gives up all locks and 
>> waits until it is notified
>> (synchronize x .notify) gets a lock on x and then notifies some thread 
>> waiting on x
>>
>> I often use the idiom
>>   (synchronize g (lambda(g) ....))
>> or
>>   (synchronize g (lambda(_) ...))
>>
>> ---Tim---
>>
>> On Wednesday, March 5, 2003, at 01:58 PM, Geoffrey Knauth wrote:
>>
>>> I can use Java threads from JScheme.
>>>
>>> But can I make JScheme variables `synchronized' ?
>>>
>>> Geoffrey
>>>
>>>
>>>
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>
>
>
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