org.eclipse.vtp.framework.util
Class SingletonTracker

java.lang.Object
  org.osgi.util.tracker.ServiceTracker
      org.eclipse.vtp.framework.util.SingletonTracker

All Implemented Interfaces:

SingletonTrackerCustomizer, org.osgi.util.tracker.ServiceTrackerCustomizer

Direct Known Subclasses:

HttpConnectorManager, LogTracker, ProcessEngineManager

public class SingletonTracker
extends org.osgi.util.tracker.ServiceTracker
implements SingletonTrackerCustomizer

A customized ServiceTracker that tracks only the single most desirable instance of a service.

Since:

3.0

Version:

1.0

Author:

Lonnie Pryor

Field Summary

Fields inherited from class org.osgi.util.tracker.ServiceTracker

context, filter

Constructor Summary

SingletonTracker(org.osgi.framework.BundleContext context, org.osgi.framework.Filter filter, SingletonTrackerCustomizer customizer)
Creates a new SingletonTracker.

SingletonTracker(org.osgi.framework.BundleContext context, org.osgi.framework.ServiceReference reference, SingletonTrackerCustomizer customizer)
Creates a new SingletonTracker.

SingletonTracker(org.osgi.framework.BundleContext context, java.lang.String clazz, SingletonTrackerCustomizer customizer)
Creates a new SingletonTracker.

Method Summary

java.lang.Object	addingService(org.osgi.framework.ServiceReference reference)
java.lang.Object	changingSelectedService(org.osgi.framework.ServiceReference oldReference, java.lang.Object oldService, org.osgi.framework.ServiceReference newReference) Called when another service besides the currently selected singleton is selected as the new singleton.
java.lang.Object	getService()
java.lang.Object	getService(org.osgi.framework.ServiceReference ref)
org.osgi.framework.ServiceReference	getServiceReference()
org.osgi.framework.ServiceReference[]	getServiceReferences()
java.lang.Object[]	getServices()
void	modifiedService(org.osgi.framework.ServiceReference reference, java.lang.Object service)
void	releasedSelectedService(org.osgi.framework.ServiceReference reference, java.lang.Object service) Called when the selected service must be released and no replacement is available.
void	removedService(org.osgi.framework.ServiceReference reference, java.lang.Object service)
void	selectedServiceModified(org.osgi.framework.ServiceReference reference, java.lang.Object service) Called when the properties of the currently selected singleton service have changed.
java.lang.Object	selectingService(org.osgi.framework.ServiceReference reference) Called when a service is selected as the singleton.
int	size()
protected void	throwableCaught(java.lang.Throwable t) Called when a method on the customizer fails to complete normally.
java.lang.Object	waitForService(long timeout)

Methods inherited from class org.osgi.util.tracker.ServiceTracker

close, getTrackingCount, open, open, remove

Methods inherited from class java.lang.Object

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

Constructor Detail

SingletonTracker

public SingletonTracker(org.osgi.framework.BundleContext context,
                        org.osgi.framework.ServiceReference reference,
                        SingletonTrackerCustomizer customizer)

Creates a new SingletonTracker.

Parameters:

context - The context to operate under.

reference - The reference to the service to track.

customizer - The customizer for this tracker or null to use this tracker as the customizer also.

SingletonTracker

public SingletonTracker(org.osgi.framework.BundleContext context,
                        java.lang.String clazz,
                        SingletonTrackerCustomizer customizer)

Creates a new SingletonTracker.

Parameters:

context - The context to operate under.

clazz - The type of service to track.

customizer - The customizer for this tracker or null to use this tracker as the customizer also.

SingletonTracker

public SingletonTracker(org.osgi.framework.BundleContext context,
                        org.osgi.framework.Filter filter,
                        SingletonTrackerCustomizer customizer)

Creates a new SingletonTracker.

Parameters:

context - The context to operate under.

filter - A filter that identifies the services to track.

customizer - The customizer for this tracker or null to use this tracker as the customizer also.

Method Detail

throwableCaught

protected void throwableCaught(java.lang.Throwable t)

Called when a method on the customizer fails to complete normally. By default the stack trace is printed and the throwable is ignored.

Parameters:

t - The throwable that was caught.

getServiceReference

public org.osgi.framework.ServiceReference getServiceReference()

Overrides:

getServiceReference in class org.osgi.util.tracker.ServiceTracker

getService

public java.lang.Object getService()

Overrides:

getService in class org.osgi.util.tracker.ServiceTracker

getServiceReferences

public org.osgi.framework.ServiceReference[] getServiceReferences()

Overrides:

getServiceReferences in class org.osgi.util.tracker.ServiceTracker

getService

public java.lang.Object getService(org.osgi.framework.ServiceReference ref)

Overrides:

getService in class org.osgi.util.tracker.ServiceTracker

getServices

public java.lang.Object[] getServices()

Overrides:

getServices in class org.osgi.util.tracker.ServiceTracker

size

public int size()

Overrides:

size in class org.osgi.util.tracker.ServiceTracker

waitForService

public java.lang.Object waitForService(long timeout)
                                throws java.lang.InterruptedException

Overrides:

waitForService in class org.osgi.util.tracker.ServiceTracker

Throws:

java.lang.InterruptedException

addingService

public final java.lang.Object addingService(org.osgi.framework.ServiceReference reference)

Specified by:

addingService in interface org.osgi.util.tracker.ServiceTrackerCustomizer

Overrides:

addingService in class org.osgi.util.tracker.ServiceTracker

modifiedService

public final void modifiedService(org.osgi.framework.ServiceReference reference,
                                  java.lang.Object service)

Specified by:

modifiedService in interface org.osgi.util.tracker.ServiceTrackerCustomizer

Overrides:

modifiedService in class org.osgi.util.tracker.ServiceTracker

removedService

public final void removedService(org.osgi.framework.ServiceReference reference,
                                 java.lang.Object service)

Specified by:

removedService in interface org.osgi.util.tracker.ServiceTrackerCustomizer

Overrides:

removedService in class org.osgi.util.tracker.ServiceTracker

selectingService

public java.lang.Object selectingService(org.osgi.framework.ServiceReference reference)

Description copied from interface: SingletonTrackerCustomizer

Called when a service is selected as the singleton.

Specified by:

selectingService in interface SingletonTrackerCustomizer

Parameters:

reference - The selected singleton service reference.

Returns:

The singleton service object or null if the specified reference should not be selected.

changingSelectedService

public java.lang.Object changingSelectedService(org.osgi.framework.ServiceReference oldReference,
                                                java.lang.Object oldService,
                                                org.osgi.framework.ServiceReference newReference)

Description copied from interface: SingletonTrackerCustomizer

Called when another service besides the currently selected singleton is selected as the new singleton. Implementations must release the old singleton if the new singleton is accepted.

Specified by:

changingSelectedService in interface SingletonTrackerCustomizer

Parameters:

oldReference - The currently selected singleton service reference.

oldService - The currently selected singleton service object.

newReference - The newly selected singleton service reference.

Returns:

The new singleton service object or null if the new reference should not be selected and the old reference should be maintained.

selectedServiceModified

public void selectedServiceModified(org.osgi.framework.ServiceReference reference,
                                    java.lang.Object service)

Description copied from interface: SingletonTrackerCustomizer

Called when the properties of the currently selected singleton service have changed.

Specified by:

selectedServiceModified in interface SingletonTrackerCustomizer

Parameters:

reference - The currently selected singleton service reference.

service - The currently selected singleton service object.

releasedSelectedService

public void releasedSelectedService(org.osgi.framework.ServiceReference reference,
                                    java.lang.Object service)

Description copied from interface: SingletonTrackerCustomizer

Called when the selected service must be released and no replacement is available.

Specified by:

releasedSelectedService in interface SingletonTrackerCustomizer

Parameters:

reference - The currently selected singleton service reference.

service - The currently selected singleton service object.