org.rapidcontext.core.task

Class Task

java.lang.Object

java.util.TimerTask

org.rapidcontext.core.task.Task

All Implemented Interfaces:

java.lang.Runnable

public abstract class Task
extends java.util.TimerTask

A scheduled background task. This class handles execution of a single task and provides some simple accessors for information about it.

Version:

1.0

Author:

Per Cederberg

Field Summary

Fields

Modifier and Type	Field and Description
java.lang.String	id The unique task identifier.
long	lastExecutionTime The last execution time (in milliseconds since Epoch) of the task.
long	nextExecutionTime The next scheduled execution time (in milliseconds since Epoch) of the task.
long	schedulerPeriod The recurring scheduler period.

Constructor Summary

Constructors

Constructor and Description
Task(java.lang.String id) Creates a new scheduler task with the provided unique id.

Method Summary

Modifier and Type	Method and Description
boolean	cancel() Cancels this scheduled task.
abstract void	execute() Executes this task.
void	run() Executes this task and updates the scheduling timers.

Methods inherited from class java.util.TimerTask

scheduledExecutionTime

Methods inherited from class java.lang.Object

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

Field Detail

id

public java.lang.String id

The unique task identifier. This is used to prevent scheduling multiple instances of the same task.

lastExecutionTime

public long lastExecutionTime

The last execution time (in milliseconds since Epoch) of the task. This value is set each time the task execution begins. Before the first run, this value will be zero (0).

nextExecutionTime

public long nextExecutionTime

The next scheduled execution time (in milliseconds since Epoch) of the task. This is an approximate value, adjusted both when task execution begins and when it terminates. The value will be set to zero (0) when a single-run task begins execution or when a recurring task is canceled.

schedulerPeriod

public long schedulerPeriod

The recurring scheduler period. This is non-zero if this task is scheduled for recurring execution.

Constructor Detail

Task

public Task(java.lang.String id)

Creates a new scheduler task with the provided unique id. The identifier is used to prevent scheduling multiple versions of the same task.

Parameters:

id - the unique task identifier

Method Detail

run

public final void run()

Executes this task and updates the scheduling timers. This method also ensures proper logging of exceptions, etc.

Specified by:

run in interface java.lang.Runnable

Specified by:

run in class java.util.TimerTask

execute

public abstract void execute()
                      throws java.lang.Exception

Executes this task.

Throws:

java.lang.Exception - if an error occurred during the execution

cancel

public boolean cancel()

Cancels this scheduled task. This method is safe to call multiple times.

Overrides:

cancel in class java.util.TimerTask

Returns:

true if the task was canceled, or false if it were no longer scheduled (already canceled)