Package de.aristaflow.adept2.core.client

Class ClientServiceSharedServices.ServiceAvailabilityTracker

java.lang.Object

de.aristaflow.adept2.core.client.ClientServiceSharedServices.ServiceAvailabilityTracker

All Implemented Interfaces:

Runnable

Enclosing class:

ClientServiceSharedServices

public static class ClientServiceSharedServices.ServiceAvailabilityTracker
extends Object
implements Runnable

A tracker for the availability of a specific ADEPT2Services. The service is polled regularly. If its availability changes (detected via ADEPT2Service.ping()) the registered listeners will be notified.
Note that polling will only take place if at least one listener is registered.

Field Summary

Fields

Modifier and Type	Field	Description
protected Collection<ClientService.ServiceStateListener>	listeners	The listeners which are registered for changes in the availability of the service.
protected Logger	logger	The logger for logging problems occurring when notifying listeners.
protected long	rate	The time in milliseconds between checking the service availability (at a fixed rate).
protected ScheduledExecutorService	scheduler	The executor service which runs the tracker regularly to check for the service availability.
protected ADEPT2Service	service	The service of which to check its availability.
protected Class<? extends ADEPT2Service>	serviceClass	The interfaces of the service.
protected URI[]	serviceUris	The URIs of the service the last time the service was available.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ServiceAvailabilityTracker(ADEPT2Service service, ScheduledExecutorService scheduler, long rate, Logger logger)	Creates a new tracker for the designated service using the designated executor service for checking the service availability.

Method Summary

Modifier and Type	Method	Description
boolean	addListener(ClientService.ServiceStateListener listener)	Adds the designated listener for changes in the availability of our ADEPT2Service.
boolean	removeServiceStateListener(ClientService.ServiceStateListener listener)	Removes the designated listener so that it is no longer notified for changes in the availability of our ADEPT2Service.
void	run()	Note that this method is called from the constructor!
protected long	serviceAvailable()	Checks whether our ADEPT2Service reacts to ADEPT2Service.ping() and gets the corresponding return value.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final Logger logger

The logger for logging problems occurring when notifying listeners.

service

protected final ADEPT2Service service

The service of which to check its availability.

serviceClass

protected final Class<? extends ADEPT2Service> serviceClass

The interfaces of the service.

serviceUris

protected URI[] serviceUris

The URIs of the service the last time the service was available.

listeners

protected final Collection<ClientService.ServiceStateListener> listeners

The listeners which are registered for changes in the availability of the service.

scheduler

protected final ScheduledExecutorService scheduler

The executor service which runs the tracker regularly to check for the service availability.

rate

protected final long rate

The time in milliseconds between checking the service availability (at a fixed rate).

Constructor Detail

ServiceAvailabilityTracker

protected ServiceAvailabilityTracker(ADEPT2Service service,
                                     ScheduledExecutorService scheduler,
                                     long rate,
                                     Logger logger)

Creates a new tracker for the designated service using the designated executor service for checking the service availability.

Parameters:

service - The service of which to check its availability.

scheduler - The executor service which runs the tracker regularly to check for the service availability.

rate - The time in milliseconds between checking the service availability (at a fixed rate).

logger - The logger for logging problems occurring when notifying listeners.

Method Detail

serviceAvailable

protected long serviceAvailable()

Checks whether our ADEPT2Service reacts to ADEPT2Service.ping() and gets the corresponding return value. Long.MIN_VALUE for a service that is currently not responding.
Note that this method may take some time, the communication timeout applies here.

Returns:

The value our ADEPT2Service returns for ADEPT2Service.ping() or Long.MIN_VALUE if communication failed.

run

public void run()

Note that this method is called from the constructor! The instance may not be fully initialised.

Specified by:

run in interface Runnable

addListener

public boolean addListener(ClientService.ServiceStateListener listener)

Adds the designated listener for changes in the availability of our ADEPT2Service.

Parameters:

listener - The listener which to notify in case the availability of our ADEPT2Service changes.

Returns:

Whether our ADEPT2Service is currently available.

removeServiceStateListener

public boolean removeServiceStateListener(ClientService.ServiceStateListener listener)

Removes the designated listener so that it is no longer notified for changes in the availability of our ADEPT2Service. If this is the last listener, the availability check will be disabled.

Parameters:

listener - The listener which to remove.

Returns:

Whether the designated listener was the last listener.