/**
* Adds a service listener to the given bundle context under the specified filter given as a
* String. The method will also retrieve <em>all</em> the services registered before the listener
* registration (that match the given filter) and will inform the listener through service events
* of type <code>REGISTERED</code>.
*
* <p>This might cause problems if a service is registered between the listener registration and
* the retrieval of existing services since the listener will receive two events for the same
* service. For most listeners implementations however, this should not be a problem
*
* @param context bundle context to register the listener with
* @param listener service listener to be registered
* @param filter OSGi filter (given as a String) for registering the listener (can be <code>null
* </code>)
* @see BundleContext#getServiceReference(String)
* @see BundleContext#getServiceReferences(String, String)
*/
public static void addServiceListener(
BundleContext context, ServiceListener listener, String filter) {
registerListener(context, listener, filter);
// now get the already registered services and call the listener
// (the listener should be able to handle duplicates)
dispatchServiceRegistrationEvents(
OsgiServiceReferenceUtils.getServiceReferences(context, filter), listener);
}
/**
* Adds a service listener to the given application context, under the specified filter given as a
* String. The method will also retrieve the <em>best matching</em> service registered before the
* listener registration and will inform the listener through a service event of type <code>
* REGISTERED</code>. This is the only difference from {@link #addServiceListener(BundleContext,
* ServiceListener, Filter)} which considers all services, not just the best match.
*
* <p>This might cause problems if a service is registered between the listener registration and
* the retrieval of existing services since the listener will receive two events for the same
* service. For most listeners implementations however, this should not be a problem
*
* @param context bundle context to register the listener with
* @param listener service listener to be registered
* @param filter OSGi filter (given as a String) for registering the listener (can be <code>null
* </code>)
* @see BundleContext#getServiceReference(String)
* @see BundleContext#getServiceReferences(String, String)
*/
public static void addSingleServiceListener(
BundleContext context, ServiceListener listener, String filter) {
registerListener(context, listener, filter);
// now get the already registered services and call the listener
// (the listener should be able to handle duplicates)
ServiceReference ref = OsgiServiceReferenceUtils.getServiceReference(context, filter);
ServiceReference[] refs = (ref == null ? null : new ServiceReference[] {ref});
dispatchServiceRegistrationEvents(refs, listener);
}