Remote OSGI over XMPP

In a previous post, I showed how real-time collaboration could be added to Eclipse/RCP apps using ECF datashare API running on the ECF XMPP provider.

One can also use ECF to make remote OSGi calls using the ECF remoteservices API.

For example, on an ECF XMPP peer that is to be the 'server' for a given service (a trivial IConcatService in this case):

  // Get ECF adapter for remote services
  IRemoteServiceContainerAdapter adapter =  ... (e.g. from contacts list)
  // Get targetID[] buddies who are to receive service registration
  ID [] targetIDs = ... (e.g. from contacts list)
  Dictionary props = new Hashtable();
  props.put(Constants.SERVICE_REGISTRATION_TARGETS,targetIDs);
  // Create service instance...this does the actual concatenate
  Object concatService = new IConcatService() {
          public String concat(String string1, String string2) {
              return string1.concat(string2);
          }
      };
  // Register service instance
  adapter.registerRemoteService(new String[] { "IConcatService" }, concatService, props);
  // Service now registered

And for clients to lookup and use the service:

   // Get adapter for accessing remote services
  IRemoteServiceContainerAdapter adapter =  ...
  // Get remote service reference
  IRemoteServiceReference[] refs = adapter.getRemoteServiceReferences(null, "IConcatService", null);
  // Get service for remote reference
  IRemoteService service = adapter.getRemoteService(refs[0]);
  // Create remote call
  IRemoteCall remoteCall =  new IRemoteCall() {
          public String getMethod() {
              return "concat";
          }
          public Object[] getParameters() {
              return new Object[] { "Eclipse", " is cool" };
          }

          public long getTimeout() {
              return 3000;
          }};
  // Call synchronously
  String result = (String) service.callSynch(remoteCall);
  System.out.println("concat result is: "+result);
  // prints out:  concat result is: Eclipse is cool

Further, note that the client can use any of the 'style's of remote invocation desired:

IRemoteService.callSynch(...)
IRemoteService.callAsynch(...)
IRemoteService.fireAsynch(...)
IRemoteService.getProxy()

With 'getProxy()' this returns an instance that implements IConcatService, and allows direct method invocation:

IConcatService concat = (IConcatService) remoteService.getProxy();
String result = concat.concat("OSGi"," is cool");
System.out.println("concat result is: "+result);
// prints out:  concat result is: OSGi is cool

There is more test and example code available here. Note that with the IRemoteService.callAsynch, callSynch, and fireAsynch methods it is not even necessary that the client have the service interface locally. All that is needed is the string identifying the desired class name.

The support for remote services on the ECF generic provider is already in ECF 1.0.0, and the support for doing remote services on XMPP will be available in ECF 1.0.2.