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Re: [ecf-dev] OSGi Container bundles for Eclipse Remote Service tutorial

Hi Wim, Scott and All,

I used the code provided by Wim in the Activator and run and Quotes consumer with the Quotes host running. All went well and in the Remote Services output i could see the following string: $Proxy1

Then i went and created my own host bundles, very similar to the Quotes host. One service interface, and one service implementation. I made sure that the OSGI configuration for the service implementation had the same parameters as the Quotes configuration, but reflecting to my services. Then i run the quotes consumer and in the remote services i got nothing. Keep in mind that i kept the
Activator.getContext().getAllServiceReferences(null, null); method with null parameters in order to get all the ServiceReferences.

What do you think might be going wrong? What i have to check in the host?



Quoting Scott Lewis <slewis@xxxxxxxxxxxxx>:

Hi Wim and All,

One thing to note about the ECF implementation WRT the
'service.imported' OSGi service property...

For ECF's impl the following code

Object o = serviceReference.getProperty("service.imported");

will result in Object o being of type 'IRemoteService'...see javadocs here


So code like this can be written (if desired...Wim's code below will
work just fine as well):

IRemoteService rs = (IRemoteService)
// use rs if non-null
if (rs != null) {

I just mention this because this is a feature unique to ECF...as the
OSGi remote services spec only defines that a remote service will have
a non-null value for "service.imported" service property...but does not
say what type that value will be (and IRemoteService allows easy access
to...e.g. asynchronous/non-blocking remote invocation).


Wim Jongman wrote:
Hi Nicholas,

There are a few ways to deal with discovered services but here is one that uses the OSGi framework.

Please take a look at the modified Activator.start method of the o.e.e.examples.remoteservices.quotes.consumer bundle . Replace the start method with this code and then connect to the yazafatutu.com <http://yazafatutu.com> server. The code will extract all services in the framework every 10 seconds and will print a list of all services and a list with remote services.

It extracts the services from the framework with /Activator.getContext().getAllServiceReferences(null, null);/
the null, null can be replaced by your specific class and filter requirements.

It then extracts the actual service from the service reference (/Activator.getContext().getService(serviceReference)/) and prints the class name.

The next loop only prints services with the property "service.imported" not equal to null. This indicates that the service is a remote property. Is it useful to know if the service is a remote service? In one way, yes. You have to adapt your programming style to be "remote aware" and realize that calls can be delayed. On the other hand, there is no difference in remote and local services from an OSGi point of view. With the discovery in place, services are "just there" to be used.

Best regards,


public void start(BundleContext bundleContext) throws Exception { Activator.context = bundleContext;

Runnable runner = new Runnable() {
public void run() {
try {
ServiceReference[] services = Activator.getContext().getAllServiceReferences(null, null);
System.out.println("All Services");
for (ServiceReference serviceReference : services) {
Object obj = Activator.getContext().getService(serviceReference);

services = Activator.getContext().getAllServiceReferences(null, null);
System.out.println("Remote Services");
for (ServiceReference serviceReference : services) {
if (serviceReference.getProperty("service.imported") != null) {
Object obj = Activator.getContext().getService(serviceReference);

} catch (InvalidSyntaxException e) {

try {
} catch (InterruptedException e) {

new Thread(this).start();

new Thread(runner).start();


On Tue, Aug 17, 2010 at 11:27 AM, Nicholas Loulloudes <loulloudes.n@xxxxxxxxxxxx <mailto:loulloudes.n@xxxxxxxxxxxx>> wrote:

   Hi Wim,

   The listener in the consumer example you have provided me, as far
   as i understand tracks for services changes and based on
   the event (i.e Registration) it shows some service details. In my
   case, how can i first get a list of all the available services?


Wim Jongman wrote:

   The service will already be available/published as a local
   service. Why not get a list of all services and display that to
   the user. You can also filter all remote services by specifying
   the remote service property in the filter.

   Look at the listener code in [1] to see an approach on publications.

   Best regards,

Wim [1] http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.ecf/examples/bundles/org.eclipse.ecf.examples.remoteservices.quotes.consumer/src/org/eclipse/ecf/examples/remoteservices/quotes/consumer/Application.java?view=markup&root=RT_Project

On Tue, Aug 17, 2010 at 8:01 AM, Markus Alexander Kuppe <ecf-dev_eclipse.org <http://ecf-dev_eclipse.org>@lemmster.de <http://lemmster.de>> wrote:

       On 08/17/2010 07:58 AM, Nicholas Loulloudes wrote:
       > Hi Markus,
       > I am experimenting with the Zookeeper code rom Wim's
       tutorial, and one
       > of the things i would like to do is to obtain a list of the
       > provided by a host.
       > I tried to use the IDiscoveryLocator interface as suggested
       in the
       > Zoodiscovery wiki, but when calling the getServices()
       method, an empty
       > array is returned.
       > Could the discovery part in OSGi assist me in getting a
       list of the
       > published services? If yes, could you direct me on how to
       achieve this?

       Question is, what is supposed to happen with the list of
       services once
       retrieved. Do you want your distribution provider to create
       and connect to each of to invoke services? Or do you just want to
       display the results and e.g. let a user choose a service

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   --     ________________________________________________________
   Nicholas Loulloudes
   PhD Candidate,

   High Performance Computing Systems Laboratory (HPCL)
   University of Cyprus,
   Nicosia, Cyprus

   Tel: +357-22892663
   Email: loulloudes.n[at]cs.ucy.ac.cy <http://cs.ucy.ac.cy>
   Web: www.cs.ucy.ac.cy/~nickl <http://www.cs.ucy.ac.cy/%7Enickl>

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