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.
ReloadingController
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. |
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.
|
public PeriodicReloadingTrigger(ReloadingController ctrl, Object ctrlParam, long triggerPeriod, TimeUnit unit, ScheduledExecutorService exec)
PeriodicReloadingTrigger
and sets all parameters.ctrl
- the ReloadingController
(must not be null)ctrlParam
- the optional parameter to be passed to the controller when doing reloading checkstriggerPeriod
- the period in which the controller is triggeredunit
- the time unit for the periodexec
- the executor service to use (can be null, then a default executor service is createdIllegalArgumentException
- if a required argument is missingpublic PeriodicReloadingTrigger(ReloadingController ctrl, Object ctrlParam, long triggerPeriod, TimeUnit unit)
PeriodicReloadingTrigger
with a default executor service.ctrl
- the ReloadingController
(must not be null)ctrlParam
- the optional parameter to be passed to the controller when doing reloading checkstriggerPeriod
- the period in which the controller is triggeredunit
- the time unit for the periodIllegalArgumentException
- if a required argument is missingpublic void start()
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.public void stop()
ReloadingController
is no more triggered. If this trigger is already
stopped, this invocation has no effect.public boolean isRunning()
public void shutdown(boolean shutdownExecutor)
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.shutdownExecutor
- a flag whether the associated ScheduledExecutorService
is to be shut downpublic void shutdown()
ScheduledExecutorService
. This is a shortcut for shutdown(true)
.shutdown(boolean)
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