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From Alexandru Popescu <the.mindstorm.mailingl...@gmail.com>
Subject Re: JCR mapping package naming
Date Thu, 09 Feb 2006 01:08:25 GMT
#: Christophe Lombart changed the world a bit at a time by saying (astral date: 2/9/2006 1:35
AM) :#
> On 2/9/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
>> Hi Chris!
>>
>> Those suggestions look really interesting.
>> But, I would really like to have a stable enough version with correct exception handling
and clean
>> code. Moreover, before starting to support advanced features, we must cover the normal
usage
>> scenarios first. Afterwards, the way is free to add support for those.
>>
> 
> Next month, one guys in my company will start the first Graffito
> modules (GraffitoNews & GraffitoForum).
> We needs inheritances, interfaces for that. I would like to start the
> implemenetation asap.
> How long is necessary for your code clean  up ? what is it exaclty ?
> Is it mainly the exception handling ?
>

Next week we are gonna start heavy usage of graffito-jcr. Considering this I need it as reliable
as 
possible :-). And by this I mean:
- me to be able to guide the team
- the tool to provide sufficient good feedback so that we will not stuck. This includes enough
API 
to handle normal scenarios, good error reporting, clean exception handling, etc.

As you said the project started as an experiment. Considering that we are gonna use it in
production 
it needs to reach a good-enough level at least. I agree that good-stuff (like the things you
were 
talking about) will be needed, but till that moment I need the above mentioned things first.
Without 
them the team will not be able to use it or will not be able to be proficient (which is definitely

not good).

I think I have finished the first round of refactoring. Now, if I find enough time I can focus
on 
inheritance. As I said in the previous mail if we are able to support inheritance in mappings
than 
this will offer a quick solution (even if not so ellegant) for a fake lazy loading, auto-updates.

I am not sure what auto-retrieve is. I have re-read your fragment but it is still not clear.
Can you 
further explain?

You should be aware of the fact that lazy-loading is a very complex task, and it cannot be
solved 
with proxies (usually the only possibility to handle it reliable is with bytecode manipulation).

Moreover, lazy-loading is opening the doors of further problems like session handling (see

OpenSessionInView approach from Spring, or HibernateInterceptor from Hibernate). Before jumping
to 
it, we have enough other things to deal with.

Once we are able to provide some inheritance support, we can immediately start working on
these 
ideas. Meanwhile, we can continue to discuss about them so that we have 'em clarified.

I am definitely not trying to freeze the status or the set of supported features. I am only
trying 
to say that we should consider them in order, so that we can start offering good solutions
for each 
stage.

best regards,

./alex
--
.w( the_mindstorm )p.


> 
>> Indeed i find interesting the lazy loading and auto-updates. Still I believe that
some of these
>> features can be supported immediately we have inheritance for example (by using light
classes).
> 
> sorry I don't understand - How can we support inheritance ?
> 
>> This
>> is the main raison I am trying to keep focus on having the full functionality in
place. Some of
>> these features are quite complex to be implemented (take for example lazy loading).
>>
> auto-retrieve, auto-update are not complex. We have to add some
> conditions in the PM.
> I think a java proxy can help for the lazy loading but yes it is more
> complex. we need to keep a reference to the PM in the java proxy.
> Inheritance, interface : that' so cool but not so easy :-) but why not
> too make some experiences, prototyping, ...
> 
>> Please don't take me wrong :-), but I would really need an usable version, before
being able to
>> start thinking at those.
> 
> Please, let's review together how we can split the work. Currently it
> is not a full time job but I can find a lot of time during the
> upcoming weeks. My plan is to start the inheritance/interface coding
> in the middle of the next week. Now, we can at least share ideas and
> speak about the design.
> 
> 
> 
> 
> 
> 
>>
>> cheers,
>>
>> ./alex
>> --
>> .w( the_mindstorm )p.
>>
>>
>>
>> #: Christophe Lombart changed the world a bit at a time by saying (astral date: 2/8/2006
11:57 PM) :#
>> > On 2/8/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
>> >
>> >> promoting it would be: "why is it portals?"
>> > Because the targeted community is mainly the ASF portal :-)
>> > We can try to write an article on the OCM concept and use graffito as
>> > an example. than, we can promote OCM on the Jackrabbit list and other
>> > areas.
>> >
>> >>
>> >> I am reviewing right now the collection converters and fixing the exception
handling. After this
>> >> step, and some small refactorings in the filters, I will be ready for interfaces/inheritance.
Once
>> >> those are done, or at least addressed we should start promoting it.
>> >>
>> > I'm interesting to add new attributes in collection-descriptor (cd)
>> > and bean-descriptor (bd) (inspired from OJB) :
>> > 1/ lazy loading  : load the bean attribute or the collection attribute
>> > when the getter method is called - not when the main object is
>> > retrieved.
>> > 2/auto retrieve . this is an alternative to the the lazy loading. If
>> > false, the bean attribute (or the collection attribute) is not
>> > retrieved. The developer can use a new method defined on the PM to
>> > load the object. I prefer the lazy loading solution but sometime it
>> > can be usefull to control when loading the attribute.
>> > 3/ auto-update: if true : when the main object is updated, the
>> > bean/collection  attribute is updated.If false, the attribute is not
>> > updated. There a lot of case when the graph is loaded (eg. one folder
>> > & its content)  and only updates are done on the main object.
>> >
>> > Those attributes should gives the possiblity to support deep JCR
>> > structures without loosing good performances.
>> >
>> > What do you think ?
>> >
>> > I'm also thinking about the inheritance/interface support :
>> > 1/ Inheritance : the class-descriptor can contain a new element like this :
>> >
>> > <class-descriptor class="CmsObjectImpl" jcrName="graffio:cmsobject">
>> >  .....
>> > </class-desciptor>
>> >
>> > <class-descriptor class="FolderImpl" jcrName=""graffito:folder >
>> >     <extent-class class-ref = "CmsObjectImpl">
>> > </class-desciptor>
>> >
>> > <class-descriptor class="ContentImpl" jcrName="graffito:content" >
>> >     <extent-class class-ref = "CmsObjectImpl">
>> > </class-desciptor>
>> >
>> > A query can be done like this :
>> >
>> > Filter filter = queryManager.createFilter(CmsObjectImpl.class);
>> > filter.setScope("/test/node1//");
>> > Query query = queryManager.createQuery(filter);
>> > Collection result = persistenceManager.getObjects(query);
>> >
>> > => if the JCR query is build with the ancestor node type, it should
>> > work with no many changes in the current code.This solution doesn't
>> > work if the nt:unstructured type is used.
>> >
>> > This is just an idea and it needs to be review in more details - what
>> > do you think ?
>> >
>> > 2/ Interface  : I don't understand why mixin node types should be use.
>> > Java interface have not some attributes. So, I don't see how it can be
>> > set into the JCR node type hierarchy.
>> > I think we can also reuse the extent-class element but more
>> > modification in the current code is required. Still thinking about
>> > that.
>> >
>> > --
>> > Best regards,
>> >
>> > Christophe
>> >
>>
>>
> 
> 
> --
> Best regards,
> 
> Christophe
> 


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