org.osgi.util.tracker
Interface ServiceTrackerCustomizer

All Known Implementing Classes:

ServiceTracker

public interface ServiceTrackerCustomizer

The ServiceTrackerCustomizer interface allows a ServiceTracker object to customize the service objects that are tracked. The ServiceTrackerCustomizer object is called when a service is being added to the ServiceTracker object. The ServiceTrackerCustomizer can then return an object for the tracked service. The ServiceTrackerCustomizer object is also called when a tracked service is modified or has been removed from the ServiceTracker object.

The methods in this interface may be called as the result of a ServiceEvent being received by a ServiceTracker object. Since ServiceEvent s are synchronously delivered by the Framework, it is highly recommended that implementations of these methods do not register (BundleContext.registerService), modify ( ServiceRegistration.setProperties) or unregister ( ServiceRegistration.unregister) a service while being synchronized on any object.

The ServiceTracker class is thread-safe. It does not call a ServiceTrackerCustomizer object while holding any locks. ServiceTrackerCustomizer implementations must also be thread-safe.

ThreadSafe

Method Summary

java.lang.Object	addingService(ServiceReference reference) A service is being added to the ServiceTracker object.
void	modifiedService(ServiceReference reference, java.lang.Object service) A service tracked by the ServiceTracker object has been modified.
void	removedService(ServiceReference reference, java.lang.Object service) A service tracked by the ServiceTracker object has been removed.

Method Detail

addingService

public java.lang.Object addingService(ServiceReference reference)

A service is being added to the ServiceTracker object.

This method is called before a service which matched the search parameters of the ServiceTracker object is added to it. This method should return the service object to be tracked for this ServiceReference object. The returned service object is stored in the ServiceTracker object and is available from the getService and getServices methods.

Parameters:

reference - Reference to service being added to the ServiceTracker object.

Returns:

The service object to be tracked for the ServiceReference object or null if the ServiceReference object should not be tracked.

modifiedService

public void modifiedService(ServiceReference reference,
                            java.lang.Object service)

A service tracked by the ServiceTracker object has been modified.

This method is called when a service being tracked by the ServiceTracker object has had it properties modified.

Parameters:

reference - Reference to service that has been modified.

service - The service object for the modified service.

removedService

public void removedService(ServiceReference reference,
                           java.lang.Object service)

A service tracked by the ServiceTracker object has been removed.

This method is called after a service is no longer being tracked by the ServiceTracker object.

Parameters:

reference - Reference to service that has been removed.

service - The service object for the removed service.