java.util

Class Timer

java.lang.Object

java.util.Timer

public class Timer
extends Object

Class to schedule tasks in a separate thread.

Each timer is associated with precisely one “execution thread”, which it uses to run TimerTask instances serially. Scheduled TimerTask instances may either be one-shot or recurring. Recurring tasks can be scheduled as fixed-period with schedule(java.util.TimerTask, java.util.Date) or as fixed-rate with scheduleAtFixedRate(java.util.TimerTask, long, long).

Timers are thread safe in the sense that several threads can operate on one instance at the same time.

Constructor Summary

Constructors

Constructor and Description
Timer() Equivalent to this(false)
Timer(boolean isDaemon) Creates a new timer with a default (unique) name.
Timer(String name) Equivalent to this(name, false).
Timer(String name, boolean isDaemon) Create a new timer with name name.

Method Summary

Modifier and Type	Method and Description
void	cancel() Cancels all remaining tasks on the timer.
protected void	finalize() Make sure the thread is stopped when the timer is garbage-collected.
int	purge() Removes all references held by this instance to cancelled timer-tasks.
void	schedule(TimerTask task, Date when) Schedules a one-shot task at a fixed time when.
void	schedule(TimerTask task, Date when, long period) Schedules a recurring fixed-period task after a fixed time when with period period.
void	schedule(TimerTask task, long delay) Schedules a one-shot task after a fixed delay delay, specified in milliseconds.
void	schedule(TimerTask task, long delay, long period) Schedules a recurring fixed-period task after a fixed delay delay with period period.
void	scheduleAtFixedRate(TimerTask task, Date when, long period) Schedules a recurring fixed-rate task after a fixed time when with period period.
void	scheduleAtFixedRate(TimerTask task, long delay, long period) Schedules a recurring fixed-rate task after a fixed delay delay with period period.

Methods inherited from class java.lang.Object

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

Constructor Detail

Timer

public Timer(String name,
             boolean isDaemon)

Create a new timer with name name. isDaemon specifies whether the execution thread is a daemon or not.

Timer

public Timer(String name)

Equivalent to this(name, false).

Timer

public Timer(boolean isDaemon)

Creates a new timer with a default (unique) name.

Timer

public Timer()

Equivalent to this(false)

Method Detail

finalize

protected void finalize()
                 throws Throwable

Make sure the thread is stopped when the timer is garbage-collected.

Overrides:

finalize in class Object

Throws:

Throwable

cancel

public void cancel()

Cancels all remaining tasks on the timer.

The task that’s currently running (if any) must be allowed to complete. No further tasks can be enqueued on this timer. Also, releases all resources associated with this timer. All subsequent calls to methods on this instance must be no-ops.

purge

public int purge()

Removes all references held by this instance to cancelled timer-tasks.

Those tasks will be collectible at the end of this method if no other references to them exist. Returns the number of tasks purged.

schedule

public void schedule(TimerTask task,
                     Date when)

Schedules a one-shot task at a fixed time when.

schedule

public void schedule(TimerTask task,
                     long delay)

Schedules a one-shot task after a fixed delay delay, specified in milliseconds.

schedule

public void schedule(TimerTask task,
                     long delay,
                     long period)

Schedules a recurring fixed-period task after a fixed delay delay with period period.

Both delay and period are specified in milliseconds.

schedule

public void schedule(TimerTask task,
                     Date when,
                     long period)

Schedules a recurring fixed-period task after a fixed time when with period period.

Period is specified in milliseconds.

scheduleAtFixedRate

public void scheduleAtFixedRate(TimerTask task,
                                long delay,
                                long period)

Schedules a recurring fixed-rate task after a fixed delay delay with period period.

Both delay and period are specified in milliseconds.

scheduleAtFixedRate

public void scheduleAtFixedRate(TimerTask task,
                                Date when,
                                long period)

Schedules a recurring fixed-rate task after a fixed time when with period period.

Period is specified in milliseconds.