Calling Web Dynpro-Model of Application-Service doesnu00B4t work.

Question

Hello!
I have created a Composite Application with Entity- and Application-Services. I have also created the WebDynpro-Model and use it in another WebDynpro application to call the services.
I have a Entity-Service 'PollCatalogue' and an Application Service 'PollCatalogueApp'.
When I call an Entity-Service to create an entity, it works:
APollCatalogue pollcat =
                    PollCatalogueServiceProxy.createPollCatalogue();
               pollcat.setName(name);
               pollcat.getAspect().sendChanges();
               IServiceFacade serviceFacade;
               serviceFacade =
                    CAFServiceFactory.getServiceFacade(diplDefinition.class);
               serviceFacade.save();
But when I call the create-Method of the Application service nothing is created:
the call is similar to above except that
PollCatalogueServiceProxy.createPollCatalogue();
is replaced by
PollCatalogueAppProxy.createPollCatalogue();
Anyway I don´t understand what is done behind the scenes. My create-Methode has one parameter name, because it is a business key. But the ServiceProxy-create-Methods do not provide a name parameter. What service-methods are called when service-facade.save() is called? In case of Entity-Service-Proxy seems to be the create method. But what if I change more than the key-parameter, what else is called? update? And in case of AppServiceProxy? ???
Does anyone understand what is going on here?
Thank you for your help.
Best regards,
Jörg

Answer 1

Hi Jorg,
About getting an exception:
IQuery query =... ;
query.execute() ;
IMessageList mList = query.getResultAspect().getMessages()
if (mList.size() > 0) {
     for (int i = 0; i < mList.size(); i++) {
         IMessage mes = (IMessage) mList.getMessage(i);
      Throwable ex = (Throwable) mes.getExtension();
     ByteArrayOutputStream bAOStream = new ByteArrayOutputStream();
     PrintStream pStream = new PrintStream( bAOStream);
     ex.printStackTrace(pStream);
        //use bAOStream in order to show stacktrace
Regarding conceptual background about Models and Proxys:
You can find some infomation about wd model:
<a href="/people/valery.silaev/blog/2005/09/09/common-model-interface Model Interface</a>
<a href="https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/cef4f43e-0d01-0010-db84-ede25c874115">WQhy to use webdynpro common model interface ?</a>
I don't know about some proxies documentation. Possible it does not exist. So, there is brief information about it:
CAF data access services - comcafruntime~uicoupling DC. There is an implementation of com.sap.tc.col.client.generic.api api. These interfaces extends generic CMI interfaces. On top of CAF data access services implementation CAF designer generates typed CMI models which you finally use. For supporting of typed CMI models CAF provides additional build-in functionality GCP(generic client proxy) which directly operates over com.sap.tc.col.client.generic.api generic implementation.
I recommend you to learn CAF data access implementation and read information about CMI model. That's not huge area and it gives you necessary understanding.
Best regards,
Aliaksei
P.S. I don't recommend to learn and investigate the GCP implementation. That's just loss of time. The only thing that you need to know there is a black box layer which converts generic CMI model to typed model. Actually you can use generic model directly without typed. To do this use the following method for service facade getting:
com.sap.caf.ui.utils.cool.CAFServiceFactory.getServiceFacade() ;
but not this one:
com.sap.caf.ui.utils.cool.CAFServiceFactory.getServiceFacade(final Class modelDefinition) ;
and also do not use generated proxies at all, just use CMI api for model info setup for model nodes and other generic CMI api.