You can use classes in the org.apache.aries.blueprint package to extend the OSGi application programming model; this third-party SPI is provided through the blueprint-1.0 server feature. You must access OSGi application bundles in to apply your extensions. In the Liberty profile, OSGi applications run as Subsystems. To locate an OSGi application you can create a ServiceTracker in a user feature.
This topic describes how the developer of a user feature can locate running OSGi applications. This task is often required for user features that provide programming model extensions to OSGi applications. For example, a new user feature might provide such extensions by implementing a new bundle extender, often referred to as a container, or, more simply, by tracking and invoking services published from within certain OSGi applications.
Such user features must use the BundleContext of a particular running OSGi application to create new BundleTracker and ServiceTracker instances. This BundleContext can be obtained from the org.osgi.service.subsystem.Subsystem that is associated with the OSGi application. The following procedure describes how to obtain that SubSystem service.
To locate an OSGi application by creating a ServiceTracker in a user feature, complete the following steps:
import org.osgi.framework.BundleContext;
import org.osgi.service.subsystem.Subsystem;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;
String SERVICE_FILTER = "(&(objectClass=org.osgi.service.subsystem.Subsystem)
(subsystem.type=osgi.subsystem.application)(subsystem.symbolicName=my.app))"
org.osgi.framework.Filter filter = ctx.createFilter(SERVICE_FILTER);
org.osgi.util.tracker.ServiceTracker<Subsystem, Subsystem> str = new ServiceTracker<Subsystem, Subsystem>(ctx, filter, null);
org.osgi.framework.Constants.OBJECTCLASS;
org.osgi.service.subsystem.SubsystemConstants.SUBSYSTEM_SYMBOLICNAME_PROPERTY;
org.osgi.service.subsystem.SubsystemConstants.SUBSYSTEM_TYPE_APPLICATION;
org.osgi.service.subsystem.SubsystemConstants.SUBSYSTEM_TYPE_PROPERTY;