org.eclipse.gemini.blueprint.util

Class OsgiListenerUtils

java.lang.Object

org.eclipse.gemini.blueprint.util.OsgiListenerUtils

public abstract class OsgiListenerUtils
extends java.lang.Object

Utility class for dealing with various OSGi listeners, mainly ServiceListeners. This class contains common functionality such as broadcasting events or safely registering an OSGi listener.

Field Summary

Fields

Modifier and Type	Field and Description
private static org.apache.commons.logging.Log	log

Constructor Summary

Constructors

Constructor and Description
OsgiListenerUtils()

Method Summary

Modifier and Type	Method and Description
static void	addServiceListener(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceListener listener, org.osgi.framework.Filter filter) Adds a service listener to the given bundle context under the specified filter.
static void	addServiceListener(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceListener listener, java.lang.String filter) Adds a service listener to the given bundle context under the specified filter given as a String.
static void	addSingleServiceListener(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceListener listener, org.osgi.framework.Filter filter) Adds a service listener to the given bundle context, under the specified filter.
static void	addSingleServiceListener(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceListener listener, java.lang.String filter) Adds a service listener to the given application context, under the specified filter given as a String.
private static void	dispatchServiceRegistrationEvents(org.osgi.framework.ServiceReference[] alreadyRegistered, org.osgi.framework.ServiceListener listener)
private static void	registerListener(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceListener listener, java.lang.String filter)
static boolean	removeServiceListener(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceListener listener) Removes a service listener from the given bundle context.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

private static final org.apache.commons.logging.Log log

Constructor Detail

OsgiListenerUtils

public OsgiListenerUtils()

Method Detail

addServiceListener

public static void addServiceListener(org.osgi.framework.BundleContext context,
                                      org.osgi.framework.ServiceListener listener,
                                      org.osgi.framework.Filter filter)

Adds a service listener to the given bundle context under the specified filter. This method will deliver synthetic events of type REGISTERED for all existing services (that match the given filter) as if the services were registered after the listener registration.

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

Parameters:

context - bundle context to register the listener with

listener - service listener to be registered

filter - OSGi filter (given as a Filter) for registering the listener (can be null)

See Also:

addServiceListener(BundleContext, ServiceListener, String)

addServiceListener

public static void addServiceListener(org.osgi.framework.BundleContext context,
                                      org.osgi.framework.ServiceListener listener,
                                      java.lang.String filter)

Adds a service listener to the given bundle context under the specified filter given as a String. The method will also retrieve all the services registered before the listener registration (that match the given filter) and will inform the listener through service events of type REGISTERED.

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

Parameters:

context - bundle context to register the listener with

listener - service listener to be registered

filter - OSGi filter (given as a String) for registering the listener (can be null)

See Also:

BundleContext.getServiceReference(String), BundleContext.getServiceReferences(String, String)

registerListener

private static void registerListener(org.osgi.framework.BundleContext context,
                                     org.osgi.framework.ServiceListener listener,
                                     java.lang.String filter)

dispatchServiceRegistrationEvents

private static void dispatchServiceRegistrationEvents(org.osgi.framework.ServiceReference[] alreadyRegistered,
                                                      org.osgi.framework.ServiceListener listener)

addSingleServiceListener

public static void addSingleServiceListener(org.osgi.framework.BundleContext context,
                                            org.osgi.framework.ServiceListener listener,
                                            org.osgi.framework.Filter filter)

Adds a service listener to the given bundle context, under the specified filter. This method will deliver at most one synthetic event of type REGISTERED for the best matching existing service as if the services were registered after the listener registration.

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

Parameters:

context - bundle context to register the listener with

listener - service listener to be registered

filter - OSGi filter (given as a Filter) for registering the listener (can be null)

See Also:

addSingleServiceListener(BundleContext, ServiceListener, String)

addSingleServiceListener

public static void addSingleServiceListener(org.osgi.framework.BundleContext context,
                                            org.osgi.framework.ServiceListener listener,
                                            java.lang.String filter)

Adds a service listener to the given application context, under the specified filter given as a String. The method will also retrieve the best matching service registered before the listener registration and will inform the listener through a service event of type REGISTERED. This is the only difference from addServiceListener(BundleContext, ServiceListener, Filter) which considers all services, not just the best match.

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

Parameters:

context - bundle context to register the listener with

listener - service listener to be registered

filter - OSGi filter (given as a String) for registering the listener (can be null)

See Also:

BundleContext.getServiceReference(String), BundleContext.getServiceReferences(String, String)

removeServiceListener

public static boolean removeServiceListener(org.osgi.framework.BundleContext context,
                                            org.osgi.framework.ServiceListener listener)

Removes a service listener from the given bundle context. This method simply takes care of any exceptions that might be thrown (in case the context is invalid).

Parameters:

context - bundle context to unregister the listener from

listener - service listener to unregister

Returns:

true if the listener unregistration has succeeded, false otherwise (for example if the bundle context is invalid)