[ Jim Fulton wrote:] > Jürgen Herrmann wrote: >> [ Jim Fulton wrote:] >> >>>Jürgen Herrmann wrote: >>> >>>>hi all! >>>> >>>>i'm trying to form a patch that will result in a method >>>>"_before_commit()" >>>>being called on each modified object in a transaction (if that method >>>>exists of course) right before commit. >>>>main sense is to automate/delay (re)cataloging. >>>> >>>>first i looked at the Transaction class, as there have been heavy >>>>modifications to it from zodb 3.2 to 3.4 >>> >>>Patching is generally a bad idea. >>> >>>I suggest creatinga new catalog (by subclassing or adapting an existing >>>one) >>>that: >>> >>>- queues updates >>> >>>- registers a before-commit callback with the TM on the first update >>> in a transaction >>> >>>- processes the queue in the callback >>> >>>I did this recently for with Zope 3's catalog and it worked very well. >>>(I happend to use subclassing and would use adaptation if I were to >>>do it again.) >>> >>>Jim >> >> >> hi jim! >> >> thanks for your reply, i already thought about such a solution and >> discarded it because it would still be necessary to call a method >> on an object to recatalog it. this step (the programmer's >> responsibility) >> i want to eliminate for several reasons. > > Which are? i have developed a framework that nicely handles many2many relations, heavily uml based, python code generation for attribute getter/setters, code generation for methods (the def only), automatic index creation... in short, i want to make everything as easy for the programmer (atm only me :) first i had the code generation framework write out an explicit self.reindex_object() at the end of each setter, ugly. it also had the drawback that setting 3 attributes caused the object to reindex itself 3 times. not the best for performance. > >> so, what i need is a way to have my mechanism called before transaction >> commits (would be possible to use the hooks provided by zodb 3.4 for >> that, sure) and cycle through all modified objects (that's where the >> hooks in 3.4 are not enough for me, they don't provide any way to access >> a list of modified objects). > > I would oppose a per-object callback mechanism. OTOH, I would not > oppose providing enough hooks to allow you to implement such a mechanism > yourself without patching ZODB. Note however, that such a mechanism might > not help you anyway, as discussed below. > >> as i showed in my first post, the callback to modified objects works >> as expected, but in the called method i'm not able to acquire the >> responsible Catalog for the modified object. > > That's because objects registered are not acquisition wrapped. > >> up to what point can i modify objects in a transaction? why doesn't >> acquisition on my objects work in Connection::tpc_begin() ??? > > The objects are not acquisition wrapped. > > IMO, ZODB is way too low a level to do what you want to do. > > Note that what you are trying to do would be easier in Zope 3 > because Zope 3 relies far less on wrappers for acquisition. > > Jim
oh well, unfortunately i began with that project about 8months ago. that time zope (x)3 was still not recommended to users on the zope mailinglist, so i went for zope2. anyways, there must be a solution to that problem. if zodb is way to low for my approach, where do i get a possibility to get notified about a imminent transaction commit? and how could i find out about the modified objects? another question: would it be possible to wrap the objects to enable acquisition in my first approach? guess i'd have to know the container for that, right (which is no problem, because i have one distinct container folder for each class)? if that works somehow, i'd bug you further to provide me with that hooks you described above :) thanks in advance for your replies... juergen herrmann _______________________________________________________________________ >> XLhost.de - eXperts in Linux hosting << Juergen Herrmann Weiherweg 10, 93051 Regensburg, Germany Fon: +49 (0)700 XLHOSTDE [0700 95467833] Fax: +49 (0)721 151 463027 ICQ: 27139974 - IRC: [EMAIL PROTECTED] WEB: http://www.XLhost.de _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
