org.lsst.ccs.services

Class AgentPeriodicTaskService

java.lang.Object

org.lsst.ccs.services.AgentPeriodicTaskService

All Implemented Interfaces:

AlertHandler, ClearAlertHandler, HasLifecycle, ServiceLifecycle, AgentMonitor, AgentService

public final class AgentPeriodicTaskService
extends Object
implements ServiceLifecycle, HasLifecycle, AgentMonitor, ClearAlertHandler, AgentService

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

Nested Class Summary

Nested classes/interfaces inherited from interface org.lsst.ccs.framework.ClearAlertHandler

ClearAlertHandler.ClearAlertCode

Constructor Summary

Constructors

Constructor and Description
AgentPeriodicTaskService()

Method Summary

Modifier and Type	Method and Description
ClearAlertHandler.ClearAlertCode	canClearAlert(Alert alert, AlertState state) Callback to clear an Alert instance.
void	createScheduler(String name, int nThreads) Create a scheduler by name and the default number of threads.
String	getAgentMonitorDescription() Get the description for this AgentMonitor.
String	getAgentMonitorStatus(boolean useCcsBuses) This method should return the string "OK" if everything is working as expected.
List<String>	getAgentPeriodicTaskNames() Get the list of names of the scheduled tasks.
String	getAgentServiceName() Get the name of this service.
Duration	getPeriodicTaskPeriod(String taskName) Get the period of a PeriodicTaks.
List<org.lsst.ccs.services.PeriodicTaskComponent.PeriodicTaskWithScheduler>	getPeriodicTasks()
void	preBuild()
void	preInit()
void	scheduleAgentPeriodicTask(AgentPeriodicTask task) Schedule a PeriodicTask.
void	scheduleAgentPeriodicTask(AgentPeriodicTask task, String schedulerName)
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.ServiceLifecycle

afterInit, afterStart, preShutdown, preStart

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

build, init, postBuild, postInit, postShutdown, postStart, shutdown, start

Methods inherited from interface org.lsst.ccs.services.AgentService

startForAgent

Constructor Detail

AgentPeriodicTaskService

public AgentPeriodicTaskService()

Method Detail

getAgentServiceName

public String getAgentServiceName()

Description copied from interface: AgentService

Get the name of this service. This name will be used to add the given service to the lookup tree.

Specified by:

getAgentServiceName in interface AgentService

Returns:

the AgentService name.

preBuild

public void preBuild()

Specified by:

preBuild in interface ServiceLifecycle

preInit

public void preInit()

Specified by:

preInit in interface ServiceLifecycle

createScheduler

public void createScheduler(String name,
                            int nThreads)

Create a scheduler by name and the default number of threads. This scheduler can be then used to schedule periodic tasks. The number of threads allocated for this scheduler can be changed via a configuration parameter.

Parameters:

name -

nThreads -

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

scheduleAgentPeriodicTask

public void scheduleAgentPeriodicTask(AgentPeriodicTask task,
                                      String schedulerName)

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.

getPeriodicTasks

public List<org.lsst.ccs.services.PeriodicTaskComponent.PeriodicTaskWithScheduler> getPeriodicTasks()

getAgentMonitorStatus

public String getAgentMonitorStatus(boolean useCcsBuses)

Description copied from interface: AgentMonitor

This method should return the string "OK" if everything is working as expected. Otherwise it should return a message explaining the problem. This method is meant to be invoked from two places: - by a JMX environment - by a periodic task within the Agent It should be quick at evaluating the Agent status. In an attempt to de-couple the status of an Agent from the status of the buses, when this method is invoked from JMX there should be no attempt at using the CCS buses. The provided boolean parameter tells if the method is being invoked form jmx or from the periodic task. Specific implementations should make sure that access to this method is synchronized.

Specified by:

getAgentMonitorStatus in interface AgentMonitor

Parameters:

useCcsBuses - a boolean to tell if the CCS buses should be used: for example to raise an Alert. This is true when the method is invoked from the periodic task. If it's invoked form JMX its value is false.

Returns:

The Status of the AgentMonitor.

getAgentMonitorDescription

public String getAgentMonitorDescription()

Description copied from interface: AgentMonitor

Get the description for this AgentMonitor. This will be used when logging check information.

Specified by:

getAgentMonitorDescription in interface AgentMonitor

Returns:

The description for this AgentMonitor.

canClearAlert

public ClearAlertHandler.ClearAlertCode canClearAlert(Alert alert,
                                                      AlertState state)

Description copied from interface: ClearAlertHandler

Callback to clear an Alert instance. Return a ClearAlertCode for the provided Alert.

Specified by:

canClearAlert in interface ClearAlertHandler

Parameters:

alert - The Alert instance to clear.

state - The AlertState for the provided Alert.

Returns:

A ClearAlertCode to indicate which action is to be taken by the framework.