I think the form beans issue is separate and probably trickier to deal with.
You might be able to get by with a check in the
HibernateWeblogManagerImpl.updateTagCount() if the object is associated with
the current Session. I'm not sure.
I had some comments on the original interchange between you and Allen. I
think this is a pretty typical architectural issue: We need Y called when
X.something() happens, but architecturally X really shouldn't have a direct
code dependency on/knowledge of Y.
One of the things I've noted in working with Roller is the lack of a defined
lifecycle and event callbacks for the app's key business objects: entry,
blog/website, user, etc.
Defining key events (basic CRUD and other object-specific events of
interest -- rendering flow perhaps) and providing some listener interfaces
and registration mechanism for those events would probably clean up this
architecture and make a lot more pluggable fun possible.
In my dreams, a radical rewrite of Roller involves this sort of modular
definition around a Spring core. Of course, we're a good distance away and
not necessarily headed there. Roller 4 maybe?
In this specific case, you might be able to do something simple along these
lines for tags, e.g.: define interface TagEventListener and class TagEvent
and have the interested managers register with the class ?
Or you could defer this type of work for later and code it directly; I agree
with Allen that you'ld probably not be setting a precedent by doing so.
--a.
----- Original Message -----
From: "Elias Torres" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, October 02, 2006 2:42 PM
Subject: Re: How to maintain tag aggregate table?
I started trying option #1 and added a method updateTagCount(String
name, WebsiteData website, int amount) to WeblogManager with respective
calls in WeblogEntryData.addTag() and WeblogEntryData.removeTag() but
ran into a wall.
The problem is in the .copyTo, .copyFrom methods which are doing copies
on detached objects (like in the WeblogEntryPageModel) so I would end up
double counting some tags.
/** returns a dummied-up weblog entry object */
public WeblogEntryData getWeblogEntry() throws RollerException
{
if (weblogEntry == null)
{
weblogEntry = new WeblogEntryData();
weblogEntry.setWebsite(getWebsite());
form.copyTo(weblogEntry,
getRequest().getLocale(),
getRequest().getParameterMap());
weblogEntry.setWebsite(weblogEntry.getWebsite());
}
return weblogEntry;
}
NOTE: I don't think we need that last call to setWebsite:
weblogEntry.setWebsite(weblogEntry.getWebsite());
Now I understand the comment in HibernatePersistenceStragegy on the
subject:
/*
technically we shouldn't have any reason to support the saving
of detached objects, so at some point we should re-evaluate this.
objects should be re-attached before being saved again. it would
be more appropriate to reject these kinds of saves because they are
not really safe.
NOTE: this may be coming from the way we use formbeans on the UI.
we very commonly repopulate all data in a pojo (including id) from
form data rather than properly loading the object from a Session
then modifying its properties.
*/
Any suggestions on how to differentiate between a copyTo/copyFrom to a
detached object so I don't recount? or should I go with the external
approach of keeping track of tags added/tags removed. It seems to me
that either way we have an issue with these detached objects.
-Elias
Allen Gilliland wrote:
Elias Torres wrote:
Everyone,
I'm changing my code that updated the aggregated tags table from using a
task to using code during the life of the request i.e. as we save each
entry.
My question is as follows:
In WeblogEntryData we have addTag() and removeTag() meaning I have two
options:
- I can call WeblogManager.updateTagStat(Tag) on each addTag/removeTag()
- I can perform the tag stats updates inside WeblogManager.save(Entry)
I don't like the first as much but the second one requires me I keep
track of added/removed tags so I can access that information at save
time. ie. entry.getAddedTags(), entry.getRemovedTags().
I would just go for the first option. It's nice if we don't have to
refer to managers from the pojos, but to not do that would make things
harder on ourselves, so just do it. I am pretty sure we are already
doing that anyways.
-- Allen
What do you think?
-Elias
