Re: Starting out with OSGi

[Vinicius Carvalho <vi...@caravelatech.com>]

Rob, I'm sorry about this dumb question, since I'm new to GWT as well. Do we
need to register every servlet we got? Or GWT works on a front controller
way?

Regards

On Mon, Dec 22, 2008 at 5:11 AM, Rob Walker <ro...@ascert.com> wrote:

>
>
> Vinicius Carvalho wrote:
>
>> Thanks Rob, your email was very helpful, we are just starting next week
>> with
>> some minor implementation on the new architecture, I'll certainly use this
>> as a reference, thanks for sharing.
>>
>>
>>
> You're very welcome.
>
> I may have missed some parts out - so if you get stuck on any of the basic
> plumbing, email Felix users and I'll see if I can help.
>
> Like I mentioned below, we saved a lot of pain by having the 3 key parts in
> one bundle:
>
>   * gwt-user.jar
>   * compiled GWT client code and resources
>   * compiled Java server code.
>
> I'm sure it's cleaner to separate some or all of these, but you'll have to
> figure a whole lot more imports and exports, and it's likely to be something
> you have to check or re-visit every GWT release. We've gone from early GWT
> beta to 1.5 with little or no change to our bundle packaging process, so
> it's been labour saving for us to use this model
>
> Regards
>
> -- Rob
>
>

Re: Starting out with OSGi

[Rob Walker <ro...@ascert.com>]

That's kind of up to you really - depending on how you want to break 
down your application into servlets, and how you want to "partition" the 
GWT RPC services you need across servlets.

Assuming your using GWT RPC (which is all we've used) then on the client 
side, you create a URL that contains the root path + the alias to the 
servlet that you want to handle the RPC.

The key thing to remember is GWT-RPC associates a back-end RPC service 
with a URL - which from my understanding means :

    * 1 URL = 1 Java interface (and it's Async proxy) for the GWT
      service client side = 1 servlet to provide the service server side

So you can think of this 1:1 mapping from URL through to GWT RPC service 
as your unit of modularity

In our app we've used around 5 or 6 top-level handling servlets e.g.

Client Services
Environment Services
Event Log

etc.

Each of these does the bridging between the incoming GWT RPC calls, and 
the back-end OSGi services that make up our core application

You could equally go with one very large "interface servlet" for all 
your calls, although that wouldn't be a very modular design it would 
involve less plumbing on the servlet side. Or you could go with separate 
servlets for every service area of your application, which would be nice 
and modular but then you'd have to create register every servlet, along 
with any framework scaffold/plumbing that your servlets need. We chose 
to break down our application's main functional areas and create a 
separate servlet for each.

Hope this helps

Regards

-- Rob

Vinicius Carvalho wrote:
> Rob, I'm sorry about this dumb question, since I'm new to GWT as well. Do we
> need to register every servlet we got? Or GWT works on a front controller
> way?
>
> Regards
>
> On Mon, Dec 22, 2008 at 5:11 AM, Rob Walker <ro...@ascert.com> wrote:
>
>   
>> Vinicius Carvalho wrote:
>>
>>     
>>> Thanks Rob, your email was very helpful, we are just starting next week
>>> with
>>> some minor implementation on the new architecture, I'll certainly use this
>>> as a reference, thanks for sharing.
>>>
>>>
>>>
>>>       
>> You're very welcome.
>>
>> I may have missed some parts out - so if you get stuck on any of the basic
>> plumbing, email Felix users and I'll see if I can help.
>>
>> Like I mentioned below, we saved a lot of pain by having the 3 key parts in
>> one bundle:
>>
>>   * gwt-user.jar
>>   * compiled GWT client code and resources
>>   * compiled Java server code.
>>
>> I'm sure it's cleaner to separate some or all of these, but you'll have to
>> figure a whole lot more imports and exports, and it's likely to be something
>> you have to check or re-visit every GWT release. We've gone from early GWT
>> beta to 1.5 with little or no change to our bundle packaging process, so
>> it's been labour saving for us to use this model
>>
>> Regards
>>
>> -- Rob
>>
>>
>>     
>
>   

-- 


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