org.apache.commons.configuration2.reloading

Class PeriodicReloadingTrigger

java.lang.Object

org.apache.commons.configuration2.reloading.PeriodicReloadingTrigger

public class PeriodicReloadingTrigger
extends Object

A timer-based trigger for reloading checks.

An instance of this class is constructed with a reference to a ReloadingController and a period. After calling the start() method a periodic task is started which calls ReloadingController.checkForReloading(Object) on the associated reloading controller. This way changes on a configuration source can be detected without client code having to poll actively. The ReloadingController will perform its checks and generates events if it detects the need for a reloading operation.

Triggering of the controller can be disabled by calling the stop() method and later be resumed by calling start() again. When the trigger is no more needed its shutdown() method should be called.

When creating an instance a ScheduledExecutorService can be provided which is then used by the object. Otherwise, a default executor service is created and used. When shutting down this object it can be specified whether the ScheduledExecutorService should be shut down, too.

Since:

2.0

See Also:

ReloadingController

Constructor Summary

Constructors

Constructor and Description
PeriodicReloadingTrigger(ReloadingController ctrl, Object ctrlParam, long triggerPeriod, TimeUnit unit) Creates a new instance of PeriodicReloadingTrigger with a default executor service.
PeriodicReloadingTrigger(ReloadingController ctrl, Object ctrlParam, long triggerPeriod, TimeUnit unit, ScheduledExecutorService exec) Creates a new instance of PeriodicReloadingTrigger and sets all parameters.

Method Summary

Modifier and Type	Method and Description
boolean	isRunning() Returns a flag whether this trigger is currently active.
void	shutdown() Shuts down this trigger and its ScheduledExecutorService.
void	shutdown(boolean shutdownExecutor) Shuts down this trigger and optionally shuts down the ScheduledExecutorService used by this object.
void	start() Starts this trigger.
void	stop() Stops this trigger.

Methods inherited from class java.lang.Object

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

Constructor Detail

PeriodicReloadingTrigger

public PeriodicReloadingTrigger(ReloadingController ctrl,
                                Object ctrlParam,
                                long triggerPeriod,
                                TimeUnit unit,
                                ScheduledExecutorService exec)

Creates a new instance of PeriodicReloadingTrigger and sets all parameters.

Parameters:

ctrl - the ReloadingController (must not be null)

ctrlParam - the optional parameter to be passed to the controller when doing reloading checks

triggerPeriod - the period in which the controller is triggered

unit - the time unit for the period

exec - the executor service to use (can be null, then a default executor service is created

Throws:

IllegalArgumentException - if a required argument is missing

PeriodicReloadingTrigger

public PeriodicReloadingTrigger(ReloadingController ctrl,
                                Object ctrlParam,
                                long triggerPeriod,
                                TimeUnit unit)

Creates a new instance of PeriodicReloadingTrigger with a default executor service.

Parameters:

ctrl - the ReloadingController (must not be null)

ctrlParam - the optional parameter to be passed to the controller when doing reloading checks

triggerPeriod - the period in which the controller is triggered

unit - the time unit for the period

Throws:

IllegalArgumentException - if a required argument is missing

Method Detail

start

public void start()

Starts this trigger. The associated ReloadingController will be triggered according to the specified period. The first triggering happens after a period. If this trigger is already started, this invocation has no effect.

stop

public void stop()

Stops this trigger. The associated ReloadingController is no more triggered. If this trigger is already stopped, this invocation has no effect.

isRunning

public boolean isRunning()

Returns a flag whether this trigger is currently active.

Returns:

a flag whether this trigger is running

shutdown

public void shutdown(boolean shutdownExecutor)

Shuts down this trigger and optionally shuts down the ScheduledExecutorService used by this object. This method should be called if this trigger is no more needed. It ensures that the trigger is stopped. If the parameter is true, the executor service is also shut down. This should be done if this trigger is the only user of this executor service.

Parameters:

shutdownExecutor - a flag whether the associated ScheduledExecutorService is to be shut down

shutdown

public void shutdown()

Shuts down this trigger and its ScheduledExecutorService. This is a shortcut for shutdown(true).

See Also:

shutdown(boolean)