modeling-users

[Modeling-users] Notification Framework v0.5 released

[Sebastien B. <sbi...@us...>]

        Hi all,

  The NotificationFramework is a python implementation of the "Observer"
Design Pattern, allowing one-to-many dependency between objects even when
they have no idea of who and where the other objects live.

This release fixes two important bugs implying:

  - addObserver() not reporting when an object tries to register two or
    more different callbacks,
=20=20
  - postNotification() copying the observers back to its own list,
    making it grow and causing degradation of performance each time it
    is called.

It also offers an implementation for RFE#742511 allowing multiple
callbacks per observer.

  The modeling framework itself is not affected by these changes and did
  not even triggered the bugs. However and since it may take advantages
  of these changes in the future, you'll probably want to upgrade your
  local copy.


-- S=E9bastien.=20

Re: [Modeling-users] Notification Framework v0.5 released

[Thorsten K. <tk...@co...>]

Hello,

first of all I would like to thank Sebastien for his work on the nice 
frameworks.

I've tested the new feature and it is possible now to add an observer 
with different methods for different Notifications.
But it should be pointed out that one has to define a value for the
key 'NOTIFICATION_CENTER_MULTIPLE_CALLBACKS_PER_OBSERVER' in the 
environment, in order to enable the new behaviour.

Sebastien, thanks again for the fast response to the feature request,

Have a nice day,
yours kodi


Sebastien Bigaret wrote:
>         Hi all,
> 
>   The NotificationFramework is a python implementation of the "Observer"
> Design Pattern, allowing one-to-many dependency between objects even when
> they have no idea of who and where the other objects live.
> 
> This release fixes two important bugs implying:
> 
>   - addObserver() not reporting when an object tries to register two or
>     more different callbacks,
>   
>   - postNotification() copying the observers back to its own list,
>     making it grow and causing degradation of performance each time it
>     is called.
> 
> It also offers an implementation for RFE#742511 allowing multiple
> callbacks per observer.
> 
>   The modeling framework itself is not affected by these changes and did
>   not even triggered the bugs. However and since it may take advantages
>   of these changes in the future, you'll probably want to upgrade your
>   local copy.
> 
> 
> -- Sébastien. 
> 
> 
> 
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Re: [Modeling-users] Notification Framework v0.5 released

[Sebastien B. <sbi...@us...>]

  Hi Kodi and all,

Kodi wrote:
> I've tested the new feature and it is possible now to add an observer
> with different methods for different Notifications.
> But it should be pointed out that one has to define a value for the
> key 'NOTIFICATION_CENTER_MULTIPLE_CALLBACKS_PER_OBSERVER' in the
> environment, in order to enable the new behaviour.

  Well, yes, that was a terse announcement. However the documentation
was updated --I've just updated it a bit more so that it's clear where
the reference documentation stands, e.g. in module NotificationCenter
cf. http://modeling.sourceforge.net/API/Notification-API/index.html

  I also forgot to mention that there is a new script
tests/compare_perfs.py for comparing the performance of the framework
when the new feature is en-/dis-abled. It is ~2.4x slower on my machine
when enabled (the modeling framework does not need it to be activated,
but of course behaves well when it is).

I wrote:
> > This release fixes two important bugs implying:
> >   - addObserver() not reporting when an object tries to register two or
> >     more different callbacks,
> >     - postNotification() copying the observers back to its own list,
> >     making it grow and causing degradation of performance each time it
> >     is called.
> >   The modeling framework itself is not affected by these changes and
> >   did not even triggered the bugs. However and since it may take
> >   advantages of these changes in the future, you'll probably want to
> >   upgrade your local copy.

  Sorry but I was a bit distracted when writing this: on the contrary
  the MDL is likely to trigger the second bug. It is revealed when a
  given notification is listened by both generic and specific observers,
  which is at least the case for MDL's GlobalIDChangedNotification
  (listened by EditingContext [generic] and DatabaseContext [specific]).

  Hence it is now *strongly recommended* that you upgrade your local
  copy with v0.5. Sorry for the wrong comment.

        Cheers,

-- S=E9bastien.