Name
TimerTask
Synopsis
This
abstract Runnable
class represents a task that is
scheduled with a Timer
object for one-time or
repeated execution in the future. You can define a task by
subclassing TimerTask
and implementing the
abstract run( )
method. Schedule the task for
future execution by passing an instance of your subclass to one of
the schedule( )
or scheduleAtFixedRate(
)
methods of Timer
. The
Timer
object will then invoke the run(
)
method at the scheduled time or times.
Call cancel( )
to cancel the one-time or repeated execution of a TimerTask(
)
. This method returns true
if a pending
execution was actually canceled. It returns false
if the task has already been canceled, was never scheduled, or was
scheduled for one-time execution and has already been executed.
scheduledExecutionTime( )
returns the time in
milliseconds at which the most recent execution of the
TimerTask
was scheduled to occur. When the host
system is heavily loaded, the run( )
method may
not be invoked exactly when scheduled. Some tasks may choose to do
nothing if they are not invoked on time. The run(
)
method can compare the return values of
scheduledExecutionTime( )
and
System.currentTimeMillis( )
to determine whether
the current invocation is sufficiently timely.
Figure 16-60. java.util.TimerTask
public abstract class TimerTask implements Runnable { // Protected Constructors protected TimerTask( );
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