Re: [Jython-users] threads in pyservlets (synchronizing?)

[Ype K. <yk...@xs...>]

Christof,

...
>
>the problem is that during concurrent requests the parameters are getting mixed up, so that user A requesting a page with the parameter alias=x gets the page from user B who requests the same page with parameter alias=y.
>i guess the problem lies in the lines
>
>#set XSL
>  self.setXSLParameter('alias', alias)
>  self.setXSLParameter('series', series)
>  self.setXSLParameter('photo', photo)
>  #output
>  res.contentType = 'text/html'
>  self.trans.transform(self.xml, StreamResult(res.outputStream))
>
>in java i would synchronize this block of statements, but how do i do this in jython as there is no synchronizing?
>i am not a java nor jython pro as you might see and i reckon there are also solutions without synchronizing.
>
>any help would be great!

I don't know about servlets, so I can't comment on that.
To get synchronisation, you can use a Lock from the thread module:

from thread import Lock

in: __init__(self):
add: self.lock = Lock()

and around your block:

self.lock.acquire()
try:
    'your block'
finally:
    self.lock.release()

When you need fifo behaviour on the acquire() call have a look
at the FIFOSemaphore from util.concurrent by Doug Lea:

http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html

Have fun,
Ype

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