public class Timer extends Object
tasks for execution.
Prefer ScheduledThreadPoolExecutor for new code.
Each timer has one thread on which tasks are executed sequentially. When this thread is busy running a task, runnable tasks may be subject to delays.
One-shot are scheduled to run at an absolute time or after a relative delay.
Recurring tasks are scheduled with either a fixed period or a fixed rate:
period.
When a timer is no longer needed, users should call cancel(), which
releases the timer's thread and other resources. Timers not explicitly
cancelled may hold resources indefinitely.
This class does not offer guarantees about the real-time nature of task scheduling. Multiple threads can share a single timer without synchronization.
| Constructor and Description |
|---|
Timer()
Creates a new non-daemon
Timer. |
Timer(boolean isDaemon)
Creates a new
Timer which may be specified to be run as a daemon thread. |
Timer(String name)
Creates a new named
Timer which does not run as a daemon thread. |
Timer(String name,
boolean isDaemon)
Creates a new named
Timer which may be specified to be run as a
daemon thread. |
| Modifier and Type | Method and Description |
|---|---|
void |
cancel()
Cancels the
Timer and all scheduled tasks. |
int |
purge()
Removes all canceled tasks from the task queue.
|
void |
schedule(TimerTask task,
Date when)
Schedule a task for single execution.
|
void |
schedule(TimerTask task,
Date when,
long period)
Schedule a task for repeated fixed-delay execution after a specific time
has been reached.
|
void |
schedule(TimerTask task,
long delay)
Schedule a task for single execution after a specified delay.
|
void |
schedule(TimerTask task,
long delay,
long period)
Schedule a task for repeated fixed-delay execution after a specific delay.
|
void |
scheduleAtFixedRate(TimerTask task,
Date when,
long period)
Schedule a task for repeated fixed-rate execution after a specific time
has been reached.
|
void |
scheduleAtFixedRate(TimerTask task,
long delay,
long period)
Schedule a task for repeated fixed-rate execution after a specific delay
has passed.
|
public Timer(String name, boolean isDaemon)
Timer which may be specified to be run as a
daemon thread.name - the name of the Timer.isDaemon - true if Timer's thread should be a daemon thread.NullPointerException - is name is nullpublic Timer(String name)
Timer which does not run as a daemon thread.name - the name of the Timer.NullPointerException - is name is nullpublic Timer(boolean isDaemon)
Timer which may be specified to be run as a daemon thread.isDaemon - true if the Timer's thread should be a daemon thread.public Timer()
Timer.public void cancel()
Timer and all scheduled tasks. If there is a
currently running task it is not affected. No more tasks may be scheduled
on this Timer. Subsequent calls do nothing.public int purge()
public void schedule(TimerTask task, Date when)
when is less than the
current time, it will be scheduled to be executed as soon as possible.task - the task to schedule.when - time of execution.IllegalArgumentException - if when.getTime() < 0.IllegalStateException - if the Timer has been canceled, or if the task has been
scheduled or canceled.public void schedule(TimerTask task, long delay)
task - the task to schedule.delay - amount of time in milliseconds before execution.IllegalArgumentException - if delay < 0.IllegalStateException - if the Timer has been canceled, or if the task has been
scheduled or canceled.public void schedule(TimerTask task, long delay, long period)
task - the task to schedule.delay - amount of time in milliseconds before first execution.period - amount of time in milliseconds between subsequent executions.IllegalArgumentException - if delay < 0 or period <= 0.IllegalStateException - if the Timer has been canceled, or if the task has been
scheduled or canceled.public void schedule(TimerTask task, Date when, long period)
task - the task to schedule.when - time of first execution.period - amount of time in milliseconds between subsequent executions.IllegalArgumentException - if when.getTime() < 0 or period <= 0.IllegalStateException - if the Timer has been canceled, or if the task has been
scheduled or canceled.public void scheduleAtFixedRate(TimerTask task, long delay, long period)
task - the task to schedule.delay - amount of time in milliseconds before first execution.period - amount of time in milliseconds between subsequent executions.IllegalArgumentException - if delay < 0 or period <= 0.IllegalStateException - if the Timer has been canceled, or if the task has been
scheduled or canceled.public void scheduleAtFixedRate(TimerTask task, Date when, long period)
task - the task to schedule.when - time of first execution.period - amount of time in milliseconds between subsequent executions.IllegalArgumentException - if when.getTime() < 0 or period <= 0.IllegalStateException - if the Timer has been canceled, or if the task has been
scheduled or canceled.