org.lsst.ccs.services

Class AgentPeriodicTaskService

java.lang.Object

org.lsst.ccs.services.AgentPeriodicTaskService

All Implemented Interfaces:

HasLifecycle

public final class AgentPeriodicTaskService
extends Object
implements HasLifecycle

A service to schedule periodic tasks. This service is responsible to manage the Agent's periodic tasks: - allow components to schedule periodic tasks - starts all the scheduled tasks once the Agent has started - stops the tasks upon shutdown It also provides utility methods to set/get the period of a task.

Author:

The LSST CCS Team

Constructor Summary

Constructors

Constructor and Description
AgentPeriodicTaskService(Agent a) Create an instance of the AgentPeriodicTaskService for a given Agent.

Method Summary

Modifier and Type	Method and Description
List<String>	getAgentPeriodicTaskNames() Get the list of names of the scheduled tasks.
Duration	getPeriodicTaskPeriod(String taskName) Get the period of a PeriodicTaks.
void	init() Called from the enclosing Subsystem at construction phase.
void	postShutdown() Called from the enclosing Subsystem when Agent.shutdown() has been called after shtudownNow has been invoked on all the children.
void	scheduleAgentPeriodicTask(AgentPeriodicTask task) Schedule a PeriodicTask.
void	setPeriodicTaskPeriod(String taskName, Duration period) Change the period of a PeriodicTask.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.lsst.ccs.framework.HasLifecycle

postInit, postStart, shutdownNow, start

Constructor Detail

AgentPeriodicTaskService

public AgentPeriodicTaskService(Agent a)

Create an instance of the AgentPeriodicTaskService for a given Agent.

Parameters:

a - The Agent this Service belongs to.

Method Detail

init

public void init()

Description copied from interface: HasLifecycle

Called from the enclosing Subsystem at construction phase.

This method is called before the children components of this object have their init method called.

At the time it is called, connection to the messaging layer is not yet done, so there should be no attempt to send messages in the body of this method. Configuration for message listening can nevertheless be done here, such as adding MessageListener objects.

It is unnecessary to call super.init()

Specified by:

init in interface HasLifecycle

postShutdown

public void postShutdown()

Description copied from interface: HasLifecycle

Called from the enclosing Subsystem when Agent.shutdown() has been called after shtudownNow has been invoked on all the children. At the time it is called :

• PhaseState is CLOSING.
• HardwareController.checkStopped() has been called

It should be overridden to free non hardware related resources.

Specified by:

postShutdown in interface HasLifecycle

scheduleAgentPeriodicTask

public void scheduleAgentPeriodicTask(AgentPeriodicTask task)

Schedule a PeriodicTask. Any CCS component can schedule an AgentPeriodicTask for execution. This method is available only using the init period of . Any invocation of this method at a later stage will result in a RuntimeException.

Parameters:

task - The PeriodicTask to schedule

getPeriodicTaskPeriod

public Duration getPeriodicTaskPeriod(String taskName)

Get the period of a PeriodicTaks.

Parameters:

taskName - The name of the task

Returns:

The periodic task period in milliseconds.

setPeriodicTaskPeriod

public void setPeriodicTaskPeriod(String taskName,
                                  Duration period)

Change the period of a PeriodicTask. If the Subsystem configuration Environment has been initialized and the Subsystem is not in INITAIL_SAFE configuration we use the configuration environment to change the period. Otherwise we simply change the AgentPeriodicTask directly.

Parameters:

taskName - The name of the task

period - The period Duration

getAgentPeriodicTaskNames

@Command(name="getAgentPeriodicTaskNames",
         description="Get the list of the names of the scheduled tasks",
         type=QUERY,
         category=SYSTEM)
public List<String> getAgentPeriodicTaskNames()

Get the list of names of the scheduled tasks.

Returns:

the Enumeration of task names.