| java.lang.Object
 org.jivesoftware.util.TaskEngine
| TaskEngine | | public class TaskEngine (Code) | | Performs tasks using worker threads. It also allows tasks to be scheduled to be
run at future dates. This class mimics relevant methods in both
ExecutorService and
Timer . Any
TimerTask that's
scheduled to be run in the future will automatically be run using the thread
executor's thread pool. This means that the standard restriction that TimerTasks
should run quickly does not apply.
author:
Matt Tucker |
| Method Summary | |
| public void | cancelScheduledTask(TimerTask task)
Cancels the execution of a scheduled task. | | public static TaskEngine | getInstance()
Returns a task engine instance (singleton). | | public void | schedule(TimerTask task, long delay)
Schedules the specified task for execution after the specified delay. | | public void | schedule(TimerTask task, Date time)
Schedules the specified task for execution at the specified time. | | public void | schedule(TimerTask task, long delay, long period)
Schedules the specified task for repeated fixed-delay execution,
beginning after the specified delay. | | public void | schedule(TimerTask task, Date firstTime, long period)
Schedules the specified task for repeated fixed-delay execution,
beginning at the specified time. | | public void | scheduleAtFixedRate(TimerTask task, long delay, long period)
Schedules the specified task for repeated fixed-rate execution,
beginning after the specified delay. | | public void | scheduleAtFixedRate(TimerTask task, Date firstTime, long period)
Schedules the specified task for repeated fixed-rate execution,
beginning at the specified time. | | public void | shutdown()
Shuts down the task engine service. | | public Future | submit(Runnable task)
Submits a Runnable task for execution and returns a Future
representing that task.
Parameters:
task - the task to submit. |
| getInstance | | public static TaskEngine getInstance()(Code) | | Returns a task engine instance (singleton).
a task engine. |
| schedule | | public void schedule(TimerTask task, long delay)(Code) | | Schedules the specified task for execution after the specified delay.
Parameters:
task - task to be scheduled.
Parameters:
delay - delay in milliseconds before task is to be executed.
throws:
IllegalArgumentException - if delay is negative, ordelay + System.currentTimeMillis() is negative.
throws:
IllegalStateException - if task was already scheduled orcancelled, or timer was cancelled. |
| schedule | | public void schedule(TimerTask task, Date time)(Code) | | Schedules the specified task for execution at the specified time. If
the time is in the past, the task is scheduled for immediate execution.
Parameters:
task - task to be scheduled.
Parameters:
time - time at which task is to be executed.
throws:
IllegalArgumentException - if time.getTime() is negative.
throws:
IllegalStateException - if task was already scheduled orcancelled, timer was cancelled, or timer thread terminated. |
| schedule | | public void schedule(TimerTask task, long delay, long period)(Code) | | Schedules the specified task for repeated fixed-delay execution,
beginning after the specified delay. Subsequent executions take place
at approximately regular intervals separated by the specified period.
In fixed-delay execution, each execution is scheduled relative to
the actual execution time of the previous execution. If an execution
is delayed for any reason (such as garbage collection or other
background activity), subsequent executions will be delayed as well.
In the long run, the frequency of execution will generally be slightly
lower than the reciprocal of the specified period (assuming the system
clock underlying Object.wait(long) is accurate).
Fixed-delay execution is appropriate for recurring activities
that require "smoothness." In other words, it is appropriate for
activities where it is more important to keep the frequency accurate
in the short run than in the long run. This includes most animation
tasks, such as blinking a cursor at regular intervals. It also includes
tasks wherein regular activity is performed in response to human
input, such as automatically repeating a character as long as a key
is held down.
Parameters:
task - task to be scheduled.
Parameters:
delay - delay in milliseconds before task is to be executed.
Parameters:
period - time in milliseconds between successive task executions.
throws:
IllegalArgumentException - if delay is negative, ordelay + System.currentTimeMillis() is negative.
throws:
IllegalStateException - if task was already scheduled orcancelled, timer was cancelled, or timer thread terminated. |
| schedule | | public void schedule(TimerTask task, Date firstTime, long period)(Code) | | Schedules the specified task for repeated fixed-delay execution,
beginning at the specified time. Subsequent executions take place at
approximately regular intervals, separated by the specified period.
In fixed-delay execution, each execution is scheduled relative to
the actual execution time of the previous execution. If an execution
is delayed for any reason (such as garbage collection or other
background activity), subsequent executions will be delayed as well.
In the long run, the frequency of execution will generally be slightly
lower than the reciprocal of the specified period (assuming the system
clock underlying Object.wait(long) is accurate).
Fixed-delay execution is appropriate for recurring activities
that require "smoothness." In other words, it is appropriate for
activities where it is more important to keep the frequency accurate
in the short run than in the long run. This includes most animation
tasks, such as blinking a cursor at regular intervals. It also includes
tasks wherein regular activity is performed in response to human
input, such as automatically repeating a character as long as a key
is held down.
Parameters:
task - task to be scheduled.
Parameters:
firstTime - First time at which task is to be executed.
Parameters:
period - time in milliseconds between successive task executions.
throws:
IllegalArgumentException - if time.getTime() is negative.
throws:
IllegalStateException - if task was already scheduled orcancelled, timer was cancelled, or timer thread terminated. |
| scheduleAtFixedRate | | public void scheduleAtFixedRate(TimerTask task, long delay, long period)(Code) | | Schedules the specified task for repeated fixed-rate execution,
beginning after the specified delay. Subsequent executions take place
at approximately regular intervals, separated by the specified period.
In fixed-rate execution, each execution is scheduled relative to the
scheduled execution time of the initial execution. If an execution is
delayed for any reason (such as garbage collection or other background
activity), two or more executions will occur in rapid succession to
"catch up." In the long run, the frequency of execution will be
exactly the reciprocal of the specified period (assuming the system
clock underlying Object.wait(long) is accurate).
Fixed-rate execution is appropriate for recurring activities that
are sensitive to absolute time, such as ringing a chime every
hour on the hour, or running scheduled maintenance every day at a
particular time. It is also appropriate for recurring activities
where the total time to perform a fixed number of executions is
important, such as a countdown timer that ticks once every second for
ten seconds. Finally, fixed-rate execution is appropriate for
scheduling multiple repeating timer tasks that must remain synchronized
with respect to one another.
Parameters:
task - task to be scheduled.
Parameters:
delay - delay in milliseconds before task is to be executed.
Parameters:
period - time in milliseconds between successive task executions.
throws:
IllegalArgumentException - if delay is negative, ordelay + System.currentTimeMillis() is negative.
throws:
IllegalStateException - if task was already scheduled orcancelled, timer was cancelled, or timer thread terminated. |
| scheduleAtFixedRate | | public void scheduleAtFixedRate(TimerTask task, Date firstTime, long period)(Code) | | Schedules the specified task for repeated fixed-rate execution,
beginning at the specified time. Subsequent executions take place at
approximately regular intervals, separated by the specified period.
In fixed-rate execution, each execution is scheduled relative to the
scheduled execution time of the initial execution. If an execution is
delayed for any reason (such as garbage collection or other background
activity), two or more executions will occur in rapid succession to
"catch up." In the long run, the frequency of execution will be
exactly the reciprocal of the specified period (assuming the system
clock underlying Object.wait(long) is accurate).
Fixed-rate execution is appropriate for recurring activities that
are sensitive to absolute time, such as ringing a chime every
hour on the hour, or running scheduled maintenance every day at a
particular time. It is also appropriate for recurring activities
where the total time to perform a fixed number of executions is
important, such as a countdown timer that ticks once every second for
ten seconds. Finally, fixed-rate execution is appropriate for
scheduling multiple repeating timer tasks that must remain synchronized
with respect to one another.
Parameters:
task - task to be scheduled.
Parameters:
firstTime - First time at which task is to be executed.
Parameters:
period - time in milliseconds between successive task executions.
throws:
IllegalArgumentException - if time.getTime() is negative.
throws:
IllegalStateException - if task was already scheduled orcancelled, timer was cancelled, or timer thread terminated. |
| shutdown | | public void shutdown()(Code) | | Shuts down the task engine service.
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