[Zope-dev] Product variable values

[Michel Pelletier]

> -----Original Message-----
> From: kent@tiamat.goathill.org [mailto:kent@tiamat.goathill.org]
> Sent: Thursday, August 05, 1999 2:43 PM
> To: zope-dev@zope.org
> Subject: [Zope-dev] Product variable values
> 
> 
> Is it possible to have class variables in a Zope Product which :
> 
> 1) are not stored in the object database
> 2) are reliably updated and retained throughout the life of a 
> zope session
>    when called by _bobo_traverse__()
> 
> I've written an example Zope Product to investigate these issues
> and cannot determine a reliable way to achieve the desired results.
> 
> '_v_name' values are only *sometimes* retained from one http get
> (via _bobo_traverse__() )to the next so those are out. I can't
> determine a pattern to when they are and when they are not. Sometimes,
> with two almost identical names, one's value is retained while the
> other's is not.

This is because _v_ objects are stored in the cache with other objects.
When the deactivator code comes around to delete some of the objects and
toss them in the persistent storage, _v_ objects are simply thrown away.
So you are correct, _v_ objects are not guarenteed to live as long as
the Zope process or between HTTP requests.

> 
> 'name' values are *sometimes* retained from one get to the next
> within a _bobo_traverse__(), and again, I can't identify when or
> why. However, changes to 'name' variables are stored in the Zope
> database, so that's also out.
> 

Sounds like you just want 'name' objects that don't subclass
Persistence.Persistent.  They won't be 'del'ed by the persistence
machinery and will go away when the process quits.

-Michel

> Thanks
> 
> 
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