Re: [corona-dev] Use Cases

[Scott Lewis <slewis@xxxxxxxxxxxxx>]

Hi Marcin and Corona folks,

Marcin Okraszewski wrote:
> I think you should take a look for ECF. They have a service repository 
> similar to the OSGi one, but services might be remote. Don't know what 
> is the default protocol for this, but I expect that the protocols are 
> pluggable, since this is how ECF is being done.

That's correct (protocols are pluggable).

ECF has a small 'remote services' API/plugin that is patterned after the 
OSGi services API.  The idea here is not to replace the OSGi services 
API, but rather expose a similar but separate API for remote 
services...so that the unique aspects of remote services are explicitly 
exposed (e.g. the occurrence and handling of network failure, the 
ability to invoke services asynchronously and/or synchronously).  See 
below for some more technical explanation of the remote services API and 
pointers to javadocs.

The API is protocol-independent...as Marcin suggests.

There's also an implementation of this API based upon the ECF generic 
provider.  It's in the plugin org.eclipse.ecf.provider.remoteservice.  
Basically what it does is use the ECF shared object API to replicate the 
remote service registry (a separate but equal service registry :).  I 
believe that Corona is using the ECF generic provider, so the API should 
already be available to the server and/or client (via 
IContainer.getAdapter(IRemoteServicesContainerAdapter).  Of course, 
alternative providers could/should be implemented (e.g. SOAP-based, 
RMI-based, REST, JXTA, jgroups, etc., etc), but we haven't done this yet.

Anyway, if desired, please feel free to ask any questions either on 
ecf-dev or on this mailing list and I'll try to answer in a timely manner.

Scott

Some more info:

The API is in the org.eclipse.ecf.remoteservices plugin.  The javadocs 
are here:

http://www.eclipse.org/ecf/org.eclipse.ecf.docs/api/

The source can be viewed here:  
http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.ecf/?root=Technology_Project

The ECF IContainer adapter interface for the remote services API is 
http://www.eclipse.org/ecf/org.eclipse.ecf.docs/api/org/eclipse/ecf/remoteservice/IRemoteServiceContainerAdapter.html.  
This API is somewhat similar to the BundleContext services API in that 
it has getRemoteServiceReferences() and registerRemoteService (similar 
to OSGi BundleContext.getServiceReferences() and 
BundleContext.registerService).

Note that instead of Object being returned from getRemoteService() 
(analogous to BundleContext.getService()), an object implementing 
IRemoteService is returned.  If you examine IRemoteService, you will see 
that there are methods for calling remote services synchronously 
(blocking call/return), asynchronously (listener), 'fire and forget', 
and ability to get access to a *local proxy*, which will expose the 
interface that the original caller of getRemoteServiceReferences() 
specified as being

Here's the source for a test case (in org.eclipse.ecf.test.remoteservice 
plugin).  This tests both the service 'server' (testRegisterService()), 
and the 'client' (testGetRemoteServiceReference, testGetRemoteService, 
testFireRemoteService, testCallRemoteServiceWithProxy, 
testCallRemoteServiceAsynch)

http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.ecf/tests/org.eclipse.ecf.test.remoteservice/src/org/eclipse/ecf/tests/remoteservice/RemoteServiceTest.java?root=Technology_Project&view=markup

Note that I'm working on replacement/new/simpler test cases for the 
remoteservices API with more extended tests.  I'm also thinking of 
introducing a RemoteServiceTracker class that would be analogous to the 
org.osgi.util.tracker.ServiceTracker class to simplify use of the remote 
services API.

Scott



> Marcin
>
>
>
> Bryan Hunt wrote:
> > Here is a set of use cases and some notes.  It's kinda high-level, 
> > but it should serve as a starting point for discussion.
> >
> > Bryan
> >
> >
> >
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