public class TaskEngine extends Object
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.| Modifier and Type | Method and Description |
|---|---|
void |
cancelScheduledTask(TimerTask task)
Cancels the execution of a scheduled task.
|
static TaskEngine |
getInstance()
Returns a task engine instance (singleton).
|
void |
schedule(TimerTask task,
Date time)
Schedules the specified task for execution at the specified time.
|
void |
schedule(TimerTask task,
Date firstTime,
long period)
Schedules the specified task for repeated fixed-delay execution,
beginning at the specified time.
|
void |
schedule(TimerTask task,
long delay)
Schedules the specified task for execution after the specified delay.
|
void |
schedule(TimerTask task,
long delay,
long period)
Schedules the specified task for repeated fixed-delay execution,
beginning after the specified delay.
|
void |
scheduleAtFixedRate(TimerTask task,
Date firstTime,
long period)
Schedules the specified task for repeated fixed-rate execution,
beginning at the specified time.
|
void |
scheduleAtFixedRate(TimerTask task,
long delay,
long period)
Schedules the specified task for repeated fixed-rate execution,
beginning after the specified delay.
|
void |
shutdown()
Shuts down the task engine service.
|
Future<?> |
submit(Runnable task)
Submits a Runnable task for execution and returns a Future
representing that task.
|
public static TaskEngine getInstance()
public Future<?> submit(Runnable task)
task - the task to submit.RejectedExecutionException - if task cannot be scheduled
for execution.NullPointerException - if task null.public void schedule(TimerTask task, long delay)
task - task to be scheduled.delay - delay in milliseconds before task is to be executed.IllegalArgumentException - if delay is negative, or
delay + System.currentTimeMillis() is negative.IllegalStateException - if task was already scheduled or
cancelled, or timer was cancelled.public void schedule(TimerTask task, Date time)
task - task to be scheduled.time - time at which task is to be executed.IllegalArgumentException - if time.getTime() is negative.IllegalStateException - if task was already scheduled or
cancelled, timer was cancelled, or timer thread terminated.public void schedule(TimerTask task, long delay, long 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.
task - task to be scheduled.delay - delay in milliseconds before task is to be executed.period - time in milliseconds between successive task executions.IllegalArgumentException - if delay is negative, or
delay + System.currentTimeMillis() is negative.IllegalStateException - if task was already scheduled or
cancelled, timer was cancelled, or timer thread terminated.public void schedule(TimerTask task, Date firstTime, long 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.
task - task to be scheduled.firstTime - First time at which task is to be executed.period - time in milliseconds between successive task executions.IllegalArgumentException - if time.getTime() is negative.IllegalStateException - if task was already scheduled or
cancelled, timer was cancelled, or timer thread terminated.public void scheduleAtFixedRate(TimerTask task, long delay, long 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.
task - task to be scheduled.delay - delay in milliseconds before task is to be executed.period - time in milliseconds between successive task executions.IllegalArgumentException - if delay is negative, or
delay + System.currentTimeMillis() is negative.IllegalStateException - if task was already scheduled or
cancelled, timer was cancelled, or timer thread terminated.public void scheduleAtFixedRate(TimerTask task, Date firstTime, long 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.
task - task to be scheduled.firstTime - First time at which task is to be executed.period - time in milliseconds between successive task executions.IllegalArgumentException - if time.getTime() is negative.IllegalStateException - if task was already scheduled or
cancelled, timer was cancelled, or timer thread terminated.public void cancelScheduledTask(TimerTask task)
TimerTask.cancel()task - the scheduled task to cancel.public void shutdown()
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