import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
+import org.osgi.util.tracker.ServiceTracker;
+import org.osgi.util.tracker.ServiceTrackerCustomizer;
-public abstract class AbstractConsumer implements Consumer, BundleActivator {
+public abstract class AbstractConsumer implements Consumer, BundleActivator,ServiceTrackerCustomizer<Broker, Broker> {
+
+
+
+
+ private BundleContext context;
+ private ServiceTracker<Broker, Broker> tracker;
+ private Broker broker;
- Broker broker;
- ServiceReference<Broker> brokerRef;
@Override
public final void start(BundleContext context) throws Exception {
+ this.context = context;
this.startImpl(context);
- brokerRef = context.getServiceReference(Broker.class);
- broker = context.getService(brokerRef);
- broker.registerConsumer(this,context);
+ tracker = new ServiceTracker<>(context, Broker.class, this);
+ tracker.open();
}
public final void stop(BundleContext context) throws Exception {
stopImpl(context);
broker = null;
- if(brokerRef != null) {
- context.ungetService(brokerRef);
- }
+ tracker.close();
}
protected void startImpl(BundleContext context) {
return Collections.emptySet();
}
+
+ @Override
+ public Broker addingService(ServiceReference<Broker> reference) {
+ if(broker == null) {
+ broker = context.getService(reference);
+ broker.registerConsumer(this, context);
+ return broker;
+ }
+
+ return null;
+ }
+
+ @Override
+ public void modifiedService(ServiceReference<Broker> reference, Broker service) {
+ // NOOP
+ }
+
+ @Override
+ public void removedService(ServiceReference<Broker> reference, Broker service) {
+ stopImpl(context);
+ }
}