Question

I can’t find information about starting and using Apache Felix from code.

I want do things which I am able (or unable 😉 ) to do with Apache Felix’s Shell.

For example, how do I start a module?

Please help.

Answer 1

So, after trying around a lot of time, here’s a possible solution.

We will have two projects:

• OsgiModuleA, which contains a module-to-be-started
• OsgiUsage, which will use the “Module A”

Project OsgiModuleA

File module/a/Activator.java

package module.a;

import org.osgi.framework.*;

public class Activator
    implements BundleActivator, ServiceListener {

  @Override
  public void start(BundleContext bc)
      throws Exception {

    System.out.println("*** started");
    bc.addServiceListener(this);
  }

  @Override
  public void stop(BundleContext bc)
      throws Exception {

    bc.removeServiceListener(this);
    System.out.println("*** stopped");
  }

  @Override
  public void serviceChanged(ServiceEvent se) {
    String s;

    switch (se.getType()) {
      case ServiceEvent.MODIFIED:
        s = "modified";
        break;
      case ServiceEvent.REGISTERED:
        s = "registered";
        break;
      case ServiceEvent.UNREGISTERING:
        s = "unregistered";
        break;
      default:
        s = "unknown";
    }

    System.out.println("= = = service changed: " + s);
  }

}

File manifest.mf

Manifest-Version: 1.0
X-COMMENT: Main-Class will be added automatically by build
Bundle-Name: Module A
Bundle-Description: Module A
Bundle-Vendor: me
Bundle-Version: 1.0.0
Bundle-Activator: module.a.Activator
Import-Package: org.osgi.framework

Project OsgiUsage

File usage/Main.java

package usage;

import java.util.*;
import org.apache.felix.framework.*;
import org.apache.felix.framework.util.*;
import org.osgi.framework.*;

public class Main {

  static class HostActivator
      implements BundleActivator {

    private BundleContext context = null;

    @Override
    public void start(BundleContext bc) {
      context = bc;
    }

    @Override
    public void stop(BundleContext bc) {
      context = null;
    }

    public BundleContext getContext() {
      return context;
    }

  }

  public static void main(String[] args)
      throws Exception {

    Map<String, Object> map = new HashMap<String, Object>();

    map.put(Constants.FRAMEWORK_SYSTEMPACKAGES_EXTRA,
        "some.module.i.dont.know; version=1.0.0");

    HostActivator activator = new HostActivator();

    List<Object> list = new LinkedList<Object>();
    list.add(activator);
    map.put(FelixConstants.SYSTEMBUNDLE_ACTIVATORS_PROP, list);

    Felix f = new Felix(map);

    System.out.println("starting OSGI...");
    f.start();

    Bundle b = f.getBundleContext().installBundle(
        "file:../OsgiModuleA/dist/OsgiModuleA.jar"); // dirty path ;)
    String bName = b.getLocation();

    System.out.println("starting bundle " + bName);
    b.start();

    Set<String> inUse = new HashSet<String>();
    for (ServiceReference sr : f.getServicesInUse()) {
      inUse.add(sr.toString());
    }
    for (ServiceReference sr : f.getRegisteredServices()) {
      String flag = (inUse.contains(sr.toString()) ? "[in use]" : "[      ]");
      System.out.println("+ registered service: " + flag + " " + sr.toString());
    }

    System.out.println("stopping bundle " + bName);
    b.stop();

    System.out.println("uninstalling bundle " + bName);
    b.uninstall();

    System.out.println("stopping...");
    f.stop();
    f.waitForStop(1000);
  }

}

Output

starting OSGI...
starting bundle file:../OsgiModuleA/dist/OsgiModuleA.jar
*** started
+ registered service: [in use] [org.osgi.service.startlevel.StartLevel]
+ registered service: [      ] [org.osgi.service.packageadmin.PackageAdmin]
stopping bundle file:../OsgiModuleA/dist/OsgiModuleA.jar
*** stopped
uninstalling bundle file:../OsgiModuleA/dist/OsgiModuleA.jar
stopping...