[Yanel-dev] Need help to figure out things

[Evaldas Taroza]

Thanks Micahel, I have a better picture now.

Evaldas

Michael Wechner wrote:
> Evaldas Taroza wrote:
> 
>> Hi,
>>
>> I still can't avoid comparing Yanel CMS framework to Servlet API. Ok 
>> ok, I know that Servlet API does not know anything about repositories 
>> nor resources, nor realms. Still
>> - A "realm" is quite similar to a "webapp"
> 
> 
> yes, there are similarities, but AFAIK one cannot make use of 
> "sub-webapps", I mean nest one webapp into the webapp
> 
> Also if one would use a webapp instead of a realm, all the core 
> functionality of Yanel would have to reployed for each webapp/realm
> 
>> - A "resource" is quite similar to a "servlet"
> 
> 
> yes, there are similarities, but for instance a resource does not have 
> to run within a servlet container, whereas I have to admit that we 
> didn't take enough care to really make this properly, because 99% of the 
> cases are running within a servlet container.
> 
> The main difference is that the resource interface is as minimal as 
> possible and all the functionality should be added through versioned 
> interfaces such that the resource stay backwards compatible
> 
>> - A "repository" is quite similar to a "db" to which a servlet can 
>> connect to
> 
> 
> yes, there are similarities ;-) but it is very important to recognize 
> the need for an abstraction layer, either through a custom data model or 
> an abstract data repository API such as Yarep or JCR. Also see
> 
> http://yanel.wyona.org/en/documentation/resources/creatable.html
> 
>>
>> To elaborate more on this similarity. A database in Servlet API can be 
>> accessed through JNDI either globally or only in a specfic context 
>> (webapp). This database can well be a Yarep or JCR repository, or any 
>> other data store. Then, I can have servlets behaving like Viewable, 
>> Creatable, Modifiable, Deletable simply by implementing doGet, doPost, 
>> etc. I have standard user's repository that I can access in each servlet.
> 
> 
> but how exactly shall the core make use of methods such as doGet and 
> doPost? I do not think that these methods are sufficient to support 
> standard CMS functionality
> 
> 
>> I can configure servlet mappings. All in all, it looks that I can do 
>> much of the stuff that I can do with Yanel.
> 
> 
> give it a try to rebuild Yanel functionality with only webapp/servlet/db 
> and I am pretty convinced you will come back to the Yanel architecture, 
> but the important thing is that you really try it :-) This is why there 
> are some many CMS out there ;-)
> 
> http://www.oscom.org/matrix/index.html
> 
>>
>> I understand, that with the Servlet API I don't talk in terms of 
>> content management as I do with Yanel. But still it looks that I can 
>> do the same with both. Actually if I had nicely called interfaces and 
>> abstract classes then I could say, that my servlet extends 
>> BasicXMLResource or something like that.
>>
>> Hm, maybe this similarity is actually a good thing...
> 
> 
> it's definitely a good thing, because it's a general pattern which is 
> true for many things. Just as the pipleine priciple of Coocon and UNIX 
> pipes is a general pattern which can be used for many things
> 
>>
>> I haven't worked with CMSs before, and probably this is my problem why 
>> I don't get it.
> 
> 
> Content Management is basically
> 
> - CRUD (Create, Read, Update, Delete)
> - Access Control
> - Workflow
> 
> One might note that one can also use SVN (Subversion) in combination 
> with WebDAV to build a content management system, whereas I do not mean 
> this in a cynical way, but rather to show how endless the possibilities 
> are to build a CMS
> 
>>
>> So can somebody clarify, why do we need such a thick layer on top of 
>> Servlet API,
> 
> 
> I don't think it's big layer at all. Please check how small the Yanel 
> core is
> 
>> when it looks more like renaming concepts than implementing something 
>> completely new and original? I may need to read about CMSs in general, 
>> but what are the most important things that a CMS should provide?
> 
> 
> try Google or see the Yanel website or see my three bullet points above
> 
>> What is it so valuable about a CMS (and maybe Yanel in particular) 
>> comparing to some Web framework like Ruby on Rails, Symphony, JBoss 
>> Seam, etc.?
> 
> 
> these are more application frameworks, but not content management 
> frameworks
> 
>>
>> I raise these questions in order not to criticize but rather to better 
>> understand Yanel.
> 
> 
> I am glad you are raising these questions, because it helps us to better 
> specify/document what we are doing and please keep asking.
> 
>>
>> Thanks for help,
> 
> 
> Hope my answers helped a bit
> 
> Cheers
> 
> Michi
> 
>> Evaldas
>>
> 
> 


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