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From Simon Nash <n...@apache.org>
Subject Re: regards my earlier questions on webapp with multiple composites / components
Date Tue, 12 Apr 2011 17:02:18 GMT
Monosij Dutta-Roy wrote:
> hi Simon - 
> Thanks for your clarifications. I will try to build upon it.
> Also I had tried the @Service(QueryService.class) you mentioned and 
> tried it again but I still get the same exception.
> I did a clean before deploy as well.
> I am attaching the composite and the interface and the class - just in 
> case I missed anything - but its pretty much same as HelloWorld example 
> webapp with the QuerySevice interface and classes and query.jsp
> I even tried variation the target from the jsp.
>         <!--reference name="service" 
> target="QueryServiceComponent/QueryService"/-->
>         <reference name="service" target="QueryServiceComponent"/>
> And am attaching the POM as well.
> Thanks Simon.
The problem is in the query.jsp file.  You need to change the line

<sca:reference name="service" type="org.rd.qm.impl.QueryServiceImpl" />


<sca:reference name="service" type="org.rd.qm.QueryService" />


> monosij
> On Mon, Apr 11, 2011 at 3:50 PM, Simon Nash <nash@apache.org 
> <mailto:nash@apache.org>> wrote:
>     Hi Monosij,
>     See comments inline.
>      Simon
>     Monosij Dutta-Roy wrote:
>         hi Ant, Simon -
>         I wanted to get back to you regards your answers on creating the
>         webapp with multiple components.
>         I hope you remember my situation with the webapp running
>         multiple contributions that I contacted you last week about.
>         ---------------------------
>         As per Ant's suggestion I moved to Tuscany version -- > 2.0-Beta2
>         And also updated namespace as: -->
>         xmlns="http://docs.oasis-open.org/ns/opencsa/sca/200912"
>         Also should this change to 2.0 or some other?
>         xmlns:tuscany="http://tuscany.apache.org/xmlns/sca/1.1"
>     1.1 should be fine.
>         However now the basic webapp while deploys in Jetty - gives an
>         error on invocation:
>         Problem accessing /qmAppSCA01/. Reason:
>         java.lang.IllegalArgumentException: Business interface
>         org.rd.qm.impl.QueryServiceImpl is not compatible with
>         org.rd.qm.QueryService
>         I have not changed the interface and classes at all from my
>         previous version which used to be invoked fine by the JSP. Again
>         this is the basic Tuscany webapp template created by Maven.
>         ---------------------------
>         I have the @Remotable on the interface org.rd.qm.QueryService as
>         below:
>         @Remotable
>         public interface QueryService {
>         String getPatients();
>         }
>         and the impl:
>         public class QueryServiceImpl implements QueryService {
>         public String getPatients() {
>         return "Got Patient!";
>         }
>         }
>         ---------------------------
>         The qmAppSCA01.composite is attached.
>         Again - this basic webapp configuration was working fine in M4
>         which I was running before. Am I missing something?
>      >
>     I think you may need to add the annotation @Service(QueryService.class)
>     to the QueryServiceImpl class.  This changed in the OASIS SCA specs
>     some time ago, and it may be that this change wasn't in 2.0-M4 but is
>     in 2.0-Beta2.
>         ---------------------------
>         Also regards my initial queries ANT ELDER wrote:
>         There is a way to do this since 2.0-M5 by putting the
>         contributions into a folder name WEB-INF/sca-contributions.
>         There is a sample which demonstrates this that we have just
>         added to the trunk samples, so its pom.xml shows what you need
>         to do, see
>         https://svn.apache.org/repos/asf/tuscany/sca-java-2.x/trunk/samples/getting-started/helloworld-webapp/
>         -----
>         I haven't gotten there yet.
>         However SIMON NASH wrote:
>         My understanding is that the JSP invokes QueryService correctly,
>         but QueryService can't invoke QueryController because
>         QueryController isn't part of the same webapp.  To fix this, you
>         could expose QueryController using an interoperable binding such
>         as binding.ws <http://binding.ws> <http://binding.ws>, and
>         configure the reference in QueryService to also use binding.ws
>         <http://binding.ws> <http://binding.ws> with an endpoint URI
>         that matches the deployment URI for QueryController. You would
>         also need to use a separate Tuscany domain (not part of the
>         webapp) to load and deploy QueryController.
>         In Tuscany 2.x (not 1.x) there is an SCA client API which allows
>         you to invoke SCA services running in a different SCA domain.
>          This is intended for use from non-SCA code, such as a servlet
>         running in a webapp.  As you are using some SCA code within the
>         webapp (though only as a UI front end) I think it's better to
>         use an interoperable binding to invoke
>         QueryController rather than using the SCA client API.
>         ---------------------------
>         Clarification seeking on which is the way to go - with my
>         interpretation as:
>         ANT's statement says that with 2.0-Beta2 I should be able to do
>         multiple components / composites for a webapp as long as I put
>         them in the WEB-INF/sca-contributions folder. So it should work
>         just by putting it there and I intend to try it out as per the
>         example.
>         However, I am interpreting SIMON's statement as a best practice
>         - and will be necessary to run the QueryController in a scalable
>         manner such as multiple nodes. So in this approach the
>         QueryController has nothing to do with the webapp but will be
>         invoked by the webapp as needed through the binding.ws
>         <http://binding.ws> <http://binding.ws> - and this leaves me
>         free to change webapp framework / UI without worrying about
>         backend logic.
>         However just for now to get things running and make sure configs
>         and such are set correctly I can get by using the approach Ant
>         suggests. However this approach won't be scalable in a way SCA
>         is meant to scale - but will be good for the prototyping phase -
>         including set up db interconnectivity through DAS and such - and
>         then when ready figure out the deployment / scaling aspect in
>         running across multiple nodes put in the ws.bindings and
>         deployment scenarios.
>         Please let me know if my interpretation is correct.
>         ---------------------------
>     Yes, that's a very good summary and it's exactly correct.
>      Simon
>         Again thanks for all your help and suggestions.
>         monosij

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