I vote for making it a parameter when you create the iterator. If
someone uses this to loop through 100k objects fetching and releasing
that memory that many times is going to be a considerable amount of
work. I seem to remember that is the reason why we made it that way.
(if not, why don't you just fetch everything and use a foreach?!?)
If you treat this as a bug and someone actually uses it to loop though
tons of objects they are justified to be pissed off.
What do you guys mean when you say it doesn't make sense from an OO
perspective?
Cheers,
Frederik
On 16/02/2009, Benjamin Eberlei <be...@mysqlusers.de> wrote:
>
> I agree to treat this as a bug, which from an OO perspective it is.
>
>
> On Mon, 16 Feb 2009 12:01:43 +0100, Tobias Schlitt <t...@ez.no> wrote:
> > Hi folks,
> >
> > during implementation of the identity map pattern for PersistentObject I
> > stumbled over a behaviour of ezcPersistentFindIterator, which I did not
> > expect:
> >
> > If you use this iterator implementation to fetch objects iteratively,
> > object instances are re-used on every iteration step. This means, the
> > state of the object returned in an iteration step is overwritten on the
> > next iteration step. A short example to illustrate this some more:
> >
> > <?php
> >
> > $itr = $session->findIterator( ... );
> >
> > $last = null;
> > foreach ( $itr as $current )
> > {
> > if ( $last !== null )
> > {
> > var_dump( $last === $current );
> > }
> > $last = $current;
> > }
> >
> > ?>
> >
> > This snippet will return true from the second iteration step on.
> >
> > We had a discussion on IRC about this behavior, which revealed that it
> > is originally by intention. I personally dislike it quite much, since it
> > can lead to real debugging pain and is not intuitive from an OO
> > perspective. It also does not save that much (memory/time), since you
> > can simple unset a created object if you don't need it anymore.
> >
> > My expectation of the find iterator class is to just fetch data from the
> > database sequentially, so you don't need to fetch all result rows at
> > once (like find() does). It should nevertheless create a new object for
> > each result row fetched.
> >
> > In addition, the behaviour dooms the find iterator feature for the
> > identity map implementation. Since the iterator overwrites object
> > states, we need to disallow this way of fetching objects for the
> > ezcPersistentIdentitySession.
> >
> > I personally would like to treat the current behavior of
> > ezcPersistentFindIterator as a bug and fix it to not overwrite object
> > states anymore.
> >
> > How do you think about this?
> >
> > Regards,
> > Toby
> > --
> > Mit freundlichen Grüßen / Med vennlig hilsen / With kind regards
> >
> > Tobias Schlitt (GPG: 0xC462BC14) eZ Components Developer
> >
> > t...@ez.no | eZ Systems AS | ez.no
> >
>
>
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>
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