org.opennms.core.tasks

Class AbstractTask

java.lang.Object

org.opennms.core.tasks.AbstractTask

All Implemented Interfaces:

Task

Direct Known Subclasses:

AsyncTask, ContainerTask, SyncTask

public abstract class AbstractTask
extends Object
implements Task

AbstractTask - Currently a collection of 'dependency' tasks defines the set of tasks that are dependents of another. - When a task completes, the set of dependency tasks are the ones that need to be considered to be run. - When a task is considered, it removes the just-completed prerequisite task from its 'prerequisites' list i.e. the set of tasks that must complete before it can run. - If the set of prerequisites for the task becomes empty, then the task can be run.

Author:

Seth, brozow

Nested Class Summary

Nested classes/interfaces inherited from interface org.opennms.core.tasks.Task

Task.State

Constructor Summary

Constructors

Constructor and Description
AbstractTask(TaskCoordinator coordinator, ContainerTask<?> parent) Constructor for Task.

Method Summary

Modifier and Type	Method and Description
protected void	addDependent(AbstractTask dependent) Adds dependent as a dependent of this task.
protected void	addPrerequisite(AbstractTask prereq) Adds prereq as a Prerequisite of this task.
protected void	completeSubmit() This method exists to allow a task to have no processing
protected void	doSubmit() This method submits a task to be executed and is called when all dependencies are completed for that task This method should place a runnable on an executor or submit the task in some other way so that it will run as soon as possible.
TaskCoordinator	getCoordinator() getCoordinator
TaskMonitor	getMonitor() getMonitor
protected boolean	isScheduled() This task has be sent to the TaskCoordinator to be run
protected void	postSchedule() postSchedule
protected void	preSchedule() preSchedule
void	schedule() This is called to add the task to the queue of tasks that can be considered to be runnable
String	toString() toString
void	waitFor() Wait for this task to complete.
boolean	waitFor(long timeout, TimeUnit unit) Wait for this task to complete or until a timeout occurs

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractTask

public AbstractTask(TaskCoordinator coordinator,
                    ContainerTask<?> parent)

Constructor for Task.

Parameters:

coordinator - a TaskCoordinator object.

parent - a ContainerTask object.

Method Detail

getCoordinator

public final TaskCoordinator getCoordinator()

getCoordinator

Specified by:

getCoordinator in interface Task

Returns:

a TaskCoordinator object.

getMonitor

public final TaskMonitor getMonitor()

getMonitor

Specified by:

getMonitor in interface Task

Returns:

a TaskMonitor object.

doSubmit

protected void doSubmit()

This method submits a task to be executed and is called when all dependencies are completed for that task This method should place a runnable on an executor or submit the task in some other way so that it will run as soon as possible. Tasks that have no processing to be done may override completeSubmit to notify the Task coordinator that the task is done.

completeSubmit

protected void completeSubmit()

This method exists to allow a task to have no processing

schedule

public final void schedule()

This is called to add the task to the queue of tasks that can be considered to be runnable

Specified by:

schedule in interface Task

preSchedule

protected void preSchedule()

preSchedule

postSchedule

protected void postSchedule()

postSchedule

isScheduled

protected final boolean isScheduled()

This task has be sent to the TaskCoordinator to be run

Returns:

a boolean.

addPrerequisite

protected void addPrerequisite(AbstractTask prereq)

Adds prereq as a Prerequisite of this task. In other words, this task cannot run until prereq has been completed.

Parameters:

prereq - a AbstractTask object.

addDependent

protected final void addDependent(AbstractTask dependent)

Adds dependent as a dependent of this task. The dependent will not be able to run until this task has been completed. TODO: Unused?

Parameters:

dependent - a AbstractTask object.

waitFor

public final void waitFor()
                   throws InterruptedException,
                          ExecutionException

Wait for this task to complete. The current thread will block until this task has been completed.

Specified by:

waitFor in interface Task

Throws:

InterruptedException - if any.

ExecutionException - if any.

waitFor

public final boolean waitFor(long timeout,
                             TimeUnit unit)
                      throws InterruptedException

Wait for this task to complete or until a timeout occurs

Specified by:

waitFor in interface Task

Parameters:

timeout - a long.

unit - a TimeUnit object.

Throws:

InterruptedException - if any.

toString

public String toString()

toString

Overrides:

toString in class Object

Returns:

a String object.