de.aristaflow.adept2.core.client

Class ClientServiceSharedServices.ServiceAvailabilityTracker

java.lang.Object

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

All Implemented Interfaces:

java.lang.Runnable

Enclosing class:

ClientServiceSharedServices

public static class ClientServiceSharedServices.ServiceAvailabilityTracker
extends java.lang.Object
implements java.lang.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 and Description
protected java.util.Collection<ClientService.ServiceStateListener>	listeners The listeners which are registered for changes in the availability of the service.
protected java.util.logging.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 java.util.concurrent.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 java.lang.Class<? extends ADEPT2Service>	serviceClass The interfaces of the service.
protected java.net.URI[]	serviceUris The URIs of the service the last time the service was available.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ServiceAvailabilityTracker(ADEPT2Service service, java.util.concurrent.ScheduledExecutorService scheduler, long rate, java.util.logging.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 and 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()
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 java.util.logging.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 java.lang.Class<? extends ADEPT2Service> serviceClass

The interfaces of the service.

serviceUris

protected java.net.URI[] serviceUris

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

listeners

protected final java.util.Collection<ClientService.ServiceStateListener> listeners

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

scheduler

protected final java.util.concurrent.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,
                                     java.util.concurrent.ScheduledExecutorService scheduler,
                                     long rate,
                                     java.util.logging.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()

Specified by:

run in interface java.lang.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.