I am trying to learn OSGI. (Mainly, the dynamic loading and unloading of bundles).
Following Neil Bartlett's tutorial for How To Embed OSGi, I added The Equinox OSGi framework implementation to the class path and started the game.
Here's the code:
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleException;
import org.osgi.framework.Constants;
import org.osgi.framework.launch.Framework;
import org.osgi.framework.launch.FrameworkFactory;
public class BundleManager {
/**
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
FrameworkFactory frameworkFactory = ServiceLoader.load(
FrameworkFactory.class).iterator().next();
Map<String, String> config = new HashMap<String, String>();
//TODO: add some config properties
Framework framework = frameworkFactory.newFramework(config);
framework.start();
BundleContext context = framework.getBundleContext();
List<Bundle> installedBundles = new LinkedList<Bundle>();
installedBundles.add(context.installBundle(
"file:C:/Users/student/Documents/eclipse/myPlugins/HellowService.jar"));
for (Bundle bundle : installedBundles) {
if (bundle.getHeaders().get(Constants.FRAGMENT_HOST) == null)
bundle.start();
}
System.out.println("done!!");
}
}
Yes, it works. No errors at all. However, the bundle that I installed which is a jar file in the path:C:/Users/student/Documents/eclipse/myPlugins/HellowService.jar
contains a "HelloWorld" in its start method. I don't see that "HelloWold" in my eclipse console. Why I don't see that message although the bundle was started? I appreciate any simple help.
Note: HellowService.jar
is a plugin project that i created earlier, implemented BundleActivator in one of its classes to add "HelloWorld" message in the start method, and finally exported it as a jar file to the directory C:/Users/student/Documents/eclipse/myPlugins/
Edit: Here's my Activator class in the bundle I am installing and starting:
package com.javaworld.sample.service.impl;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;
import com.javaworld.sample.service.HelloService;
public class HelloServiceActivator implements BundleActivator {
ServiceRegistration helloServiceRegistration;
public void start(BundleContext context) throws Exception {
HelloServiceFactory helloServiceFactory = new HelloServiceFactory();
helloServiceRegistration =context.registerService(HelloService.class.getName(), helloServiceFactory, null);
System.out.println("Hello World!");
}
public void stop(BundleContext context) throws Exception {
helloServiceRegistration.unregister();
}
}
And here's the MANIFEST.MF file of the bundle:
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: HelloService
Bundle-SymbolicName: com.javaworld.sample.HelloService
Bundle-Version: 1.0.0.qualifier
Bundle-Activator: com.javaworld.sample.service.impl.HelloServiceActivator
Bundle-Vendor: JAVAWORLD
Bundle-RequiredExecutionEnvironment: JavaSE-1.7
Import-Package: org.osgi.framework;version="1.3.0"
Export-Package: com.javaworld.sample.service
The way i export the bundle is by Right Click on the bundle project->Export->Runnable Jar File->then I select the Launch Configuration to be BundleManager (Which is the class installing the bundle).
I still do not see "Hello World!" message when I start the bundle from my application.