Class ServiceTracker<S, T, U extends org.osgi.framework.ServiceEvent>

java.lang.Object

org.apache.felix.scr.impl.manager.ServiceTracker<S,T,U>

Type Parameters:

S -

T -

public class ServiceTracker<S, T, U extends org.osgi.framework.ServiceEvent>
extends Object

changes from osgi service tracker: - included AbstractTracked as an inner class. - addedService method on customizer called after the object is tracked. - we always track all matching services.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) class	ServiceTracker.AbstractTracked<S,T,R>	Abstract class to track items.
private class	ServiceTracker.Tracked	Inner class which subclasses AbstractTracked.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	active	whether the DependencyManager is getting the service immediately.
protected final org.osgi.framework.BundleContext	context	The Bundle Context used by this ServiceTracker.
(package private) final ServiceTrackerCustomizer<S,T,U>	customizer	The ServiceTrackerCustomizer for this tracker.
(package private) static final boolean	DEBUG
private ExtendedServiceListenerContext<U>	extendedServiceListenerContext
(package private) final String	initialReferenceFilterString	Filter string for use when adding the ServiceListener.
private ServiceTracker<S,T,U>.Tracked	tracked	Tracked services: ServiceReference -> customized Object and ServiceListener object

Constructor Summary

Constructors

Constructor	Description
ServiceTracker(org.osgi.framework.BundleContext context, ServiceTrackerCustomizer<S,T,U> customizer, boolean initialActive, ExtendedServiceListenerContext<U> bundleComponentActivator, String initialReferenceFilterString)	Create a ServiceTracker on the specified Filter object.

Method Summary

Modifier and Type	Method	Description
T	addingService(org.osgi.framework.ServiceReference<S> reference, int trackingCount)	Default implementation of the ServiceTrackerCustomizer.addingService method.
SortedMap<org.osgi.framework.ServiceReference<S>, T>	close(AtomicInteger trackingCount)	Close this ServiceTracker.
void	completeClose(Map<org.osgi.framework.ServiceReference<S>, T> toUntrack)
(package private) void	deactivate()
private org.osgi.framework.ServiceReference<S>[]	getInitialReferences(String className, String filterString)	Returns the list of initial ServiceReferences that will be tracked by this ServiceTracker.
T	getService(org.osgi.framework.ServiceReference<S> reference)	Returns the service object for the specified ServiceReference if the specified referenced service is being tracked by this ServiceTracker.
int	getServiceCount()
org.osgi.framework.ServiceReference<S>[]	getServiceReferences()	Return an array of ServiceReferences for all services being tracked by this ServiceTracker.
Object[]	getServices()	Return an array of service objects for all services being tracked by this ServiceTracker.
T[]	getServices(T[] array)	Return an array of service objects for all services being tracked by this ServiceTracker.
SortedMap<org.osgi.framework.ServiceReference<S>, T>	getTracked(Boolean activate, AtomicInteger trackingCount)	Return a SortedMap of the ServiceReferences and service objects for all services being tracked by this ServiceTracker.
int	getTrackingCount()	Returns the tracking count for this ServiceTracker.
boolean	isActive()
boolean	isEmpty()	Return if this ServiceTracker is empty.
(package private) void	modified()	Called by the Tracked object whenever the set of tracked services is modified.
void	modifiedService(org.osgi.framework.ServiceReference<S> reference, T service, int trackingCount)	Default implementation of the ServiceTrackerCustomizer.modifiedService method.
void	open(boolean trackAllServices, AtomicInteger trackingCount)	Open this ServiceTracker and begin tracking services.
void	open(AtomicInteger trackingCount)	Open this ServiceTracker and begin tracking services.
void	remove(org.osgi.framework.ServiceReference<S> reference)	Remove a service from this ServiceTracker.
void	removedService(org.osgi.framework.ServiceReference<S> reference, T service, int trackingCount)	Default implementation of the ServiceTrackerCustomizer.removedService method.
int	size()	Return the number of services being tracked by this ServiceTracker.
ServiceTracker<S,T,U>.Tracked	tracked()	Accessor method for the current Tracked object.

Methods inherited from class Object

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

Field Details

DEBUG

static final boolean DEBUG

See Also:

• Constant Field Values

context

protected final org.osgi.framework.BundleContext context

The Bundle Context used by this ServiceTracker.

customizer

final ServiceTrackerCustomizer<S, T, U extends org.osgi.framework.ServiceEvent> customizer

The ServiceTrackerCustomizer for this tracker.

initialReferenceFilterString

final String initialReferenceFilterString

Filter string for use when adding the ServiceListener. If this field is set, then certain optimizations can be taken since we don't have a user supplied filter.

tracked

private volatile ServiceTracker<S, T, U extends org.osgi.framework.ServiceEvent>.Tracked tracked

Tracked services: ServiceReference -> customized Object and ServiceListener object

active

private boolean active

whether the DependencyManager is getting the service immediately.

extendedServiceListenerContext

private ExtendedServiceListenerContext<U extends org.osgi.framework.ServiceEvent> extendedServiceListenerContext

Constructor Details

ServiceTracker

public ServiceTracker(org.osgi.framework.BundleContext context,
 ServiceTrackerCustomizer<S,T,U> customizer,
 boolean initialActive,
 ExtendedServiceListenerContext<U> bundleComponentActivator,
 String initialReferenceFilterString)

Create a ServiceTracker on the specified Filter object.

Services which match the specified Filter object will be tracked by this ServiceTracker.

Parameters:

context - The BundleContext against which the tracking is done.

customizer - The customizer object to call when services are added, modified, or removed in this ServiceTracker. If customizer is null, then this ServiceTracker will be used as the ServiceTrackerCustomizer and this ServiceTracker will call the ServiceTrackerCustomizer methods on itself.

initialActive - Initial active state of the tracker.

bundleComponentActivator - TODO

initialReferenceFilterString - TODO

Since:

1.1

Method Details

tracked

public ServiceTracker<S,T,U>.Tracked tracked()

Accessor method for the current Tracked object. This method is only intended to be used by the unsynchronized methods which do not modify the tracked field.

Returns:

The current Tracked object.

open

public void open(AtomicInteger trackingCount)

Open this ServiceTracker and begin tracking services.

This implementation calls open(false).

Parameters:

trackingCount -

Throws:

IllegalStateException - If the BundleContext with which this ServiceTracker was created is no longer valid.

See Also:

• open(boolean, java.util.concurrent.atomic.AtomicInteger)

open

public void open(boolean trackAllServices,
 AtomicInteger trackingCount)

Open this ServiceTracker and begin tracking services.

Services which match the search criteria specified when this ServiceTracker was created are now tracked by this ServiceTracker.

Parameters:

trackAllServices - If true, then this ServiceTracker will track all matching services regardless of class loader accessibility. If false, then this ServiceTracker will only track matching services which are class loader accessible to the bundle whose BundleContext is used by this ServiceTracker.

trackingCount -

Throws:

IllegalStateException - If the BundleContext with which this ServiceTracker was created is no longer valid.

Since:

1.3

getInitialReferences

private org.osgi.framework.ServiceReference<S>[] getInitialReferences(String className,
 String filterString)
                                                               throws org.osgi.framework.InvalidSyntaxException

Returns the list of initial ServiceReferences that will be tracked by this ServiceTracker.

Parameters:

className - The class name with which the service was registered, or null for all services.

filterString - The filter criteria or null for all services.

Returns:

The list of initial ServiceReferences.

Throws:

org.osgi.framework.InvalidSyntaxException - If the specified filterString has an invalid syntax.

close

public SortedMap<org.osgi.framework.ServiceReference<S>, T> close(AtomicInteger trackingCount)

Close this ServiceTracker.

This method should be called when this ServiceTracker should end the tracking of services.

This implementation calls getServiceReferences() to get the list of tracked services to remove.

Parameters:

trackingCount -

completeClose

public void completeClose(Map<org.osgi.framework.ServiceReference<S>, T> toUntrack)

addingService

public T addingService(org.osgi.framework.ServiceReference<S> reference,
 int trackingCount)

Default implementation of the ServiceTrackerCustomizer.addingService method.

This method is only called when this ServiceTracker has been constructed with a null ServiceTrackerCustomizer argument.

This implementation returns the result of calling getService on the BundleContext with which this ServiceTracker was created passing the specified ServiceReference.

This method can be overridden in a subclass to customize the service object to be tracked for the service being added. In that case, take care not to rely on the default implementation of removedService to unget the service.

Parameters:

reference - The reference to the service being added to this ServiceTracker.

Returns:

The service object to be tracked for the service added to this ServiceTracker.

modifiedService

public void modifiedService(org.osgi.framework.ServiceReference<S> reference,
 T service,
 int trackingCount)

Default implementation of the ServiceTrackerCustomizer.modifiedService method.

This method is only called when this ServiceTracker has been constructed with a null ServiceTrackerCustomizer argument.

This implementation does nothing.

Parameters:

reference - The reference to modified service.

service - The service object for the modified service.

See Also:

• ServiceTrackerCustomizer.modifiedService(org.osgi.framework.ServiceReference, Object, int, ServiceEvent)

removedService

public void removedService(org.osgi.framework.ServiceReference<S> reference,
 T service,
 int trackingCount)

Default implementation of the ServiceTrackerCustomizer.removedService method.

This method is only called when this ServiceTracker has been constructed with a null ServiceTrackerCustomizer argument.

This implementation calls ungetService, on the BundleContext with which this ServiceTracker was created, passing the specified ServiceReference.

This method can be overridden in a subclass. If the default implementation of addingService method was used, this method must unget the service.

Parameters:

reference - The reference to removed service.

service - The service object for the removed service.

See Also:

• ServiceTrackerCustomizer.removedService(org.osgi.framework.ServiceReference, Object, int, ServiceEvent)

getServiceReferences

public org.osgi.framework.ServiceReference<S>[] getServiceReferences()

Return an array of ServiceReferences for all services being tracked by this ServiceTracker.

Returns:

Array of ServiceReferences or null if no services are being tracked.

getService

public T getService(org.osgi.framework.ServiceReference<S> reference)

Returns the service object for the specified ServiceReference if the specified referenced service is being tracked by this ServiceTracker.

Parameters:

reference - The reference to the desired service.

Returns:

A service object or null if the service referenced by the specified ServiceReference is not being tracked.

getServices

public Object[] getServices()

Return an array of service objects for all services being tracked by this ServiceTracker.

This implementation calls getServiceReferences() to get the list of references for the tracked services and then calls getService(ServiceReference) for each reference to get the tracked service object.

Returns:

An array of service objects or null if no services are being tracked.

remove

public void remove(org.osgi.framework.ServiceReference<S> reference)

Remove a service from this ServiceTracker. The specified service will be removed from this ServiceTracker. If the specified service was being tracked then the ServiceTrackerCustomizer.removedService method will be called for that service.

Parameters:

reference - The reference to the service to be removed.

size

public int size()

Return the number of services being tracked by this ServiceTracker.

Returns:

The number of services being tracked.

getTrackingCount

public int getTrackingCount()

Returns the tracking count for this ServiceTracker. The tracking count is initialized to 0 when this ServiceTracker is opened. Every time a service is added, modified or removed from this ServiceTracker, the tracking count is incremented.

The tracking count can be used to determine if this ServiceTracker has added, modified or removed a service by comparing a tracking count value previously collected with the current tracking count value. If the value has not changed, then no service has been added, modified or removed from this ServiceTracker since the previous tracking count was collected.

Returns:

The tracking count for this ServiceTracker or -1 if this ServiceTracker is not open.

Since:

1.2

modified

void modified()

Called by the Tracked object whenever the set of tracked services is modified. Clears the cache.

getTracked

public SortedMap<org.osgi.framework.ServiceReference<S>, T> getTracked(Boolean activate,
 AtomicInteger trackingCount)

Return a SortedMap of the ServiceReferences and service objects for all services being tracked by this ServiceTracker. The map is sorted in reverse natural order of ServiceReference. That is, the first entry is the service with the highest ranking and the lowest service id.

Parameters:

activate -

trackingCount -

Returns:

A SortedMap with the ServiceReferences and service objects for all services being tracked by this ServiceTracker. If no services are being tracked, then the returned map is empty.

Since:

1.5

deactivate

void deactivate()

isEmpty

public boolean isEmpty()

Return if this ServiceTracker is empty.

Returns:

true if this ServiceTracker is not tracking any services.

Since:

1.5

getServiceCount

public int getServiceCount()

isActive

public boolean isActive()

getServices

public T[] getServices(T[] array)

Return an array of service objects for all services being tracked by this ServiceTracker. The runtime type of the returned array is that of the specified array.

This implementation calls getServiceReferences() to get the list of references for the tracked services and then calls getService(ServiceReference) for each reference to get the tracked service object.

Parameters:

array - An array into which the tracked service objects will be stored, if the array is large enough.

Returns:

An array of service objects being tracked. If the specified array is large enough to hold the result, then the specified array is returned. If the specified array is longer then necessary to hold the result, the array element after the last service object is set to null. If the specified array is not large enough to hold the result, a new array is created and returned.

Since:

1.5