Known Direct Subclasses
CountedTimerTask |
A TimerTask subclass that keeps a count of the number of executions
of the task. |
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Class Overview
A task that can be scheduled for one-time or repeated execution by a Timer.
Summary
Protected Constructors |
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TimerTask()
Creates a new timer task.
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Public Methods |
boolean
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cancel()
Cancels this timer task.
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abstract
void
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run()
The action to be performed by this timer task.
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long
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scheduledExecutionTime()
Returns the scheduled execution time of the most recent
actual execution of this task.
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[Expand]
Inherited Methods |
From class
java.lang.Object
Object
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clone()
Creates and returns a copy of this object.
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boolean
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equals(Object obj)
Indicates whether some other object is "equal to" this one.
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void
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finalize()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
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final
Class<?>
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getClass()
Returns the runtime class of this Object .
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int
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hashCode()
Returns a hash code value for the object.
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final
void
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notify()
Wakes up a single thread that is waiting on this object's
monitor.
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final
void
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notifyAll()
Wakes up all threads that are waiting on this object's monitor.
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String
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toString()
Returns a string representation of the object.
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final
void
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wait()
Causes the current thread to wait until another thread invokes the
notify() method or the
notifyAll() method for this object.
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final
void
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wait(long timeout, int nanos)
Causes the current thread to wait until another thread invokes the
notify() method or the
notifyAll() method for this object, or
some other thread interrupts the current thread, or a certain
amount of real time has elapsed.
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final
void
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wait(long timeout)
Causes the current thread to wait until either another thread invokes the
notify() method or the
notifyAll() method for this object, or a
specified amount of time has elapsed.
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From interface
java.lang.Runnable
abstract
void
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run()
When an object implementing interface Runnable is used
to create a thread, starting the thread causes the object's
run method to be called in that separately executing
thread.
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Protected Constructors
protected
TimerTask
()
Creates a new timer task.
Public Methods
public
boolean
cancel
()
Cancels this timer task. If the task has been scheduled for one-time
execution and has not yet run, or has not yet been scheduled, it will
never run. If the task has been scheduled for repeated execution, it
will never run again. (If the task is running when this call occurs,
the task will run to completion, but will never run again.)
Note that calling this method from within the run method of
a repeating timer task absolutely guarantees that the timer task will
not run again.
This method may be called repeatedly; the second and subsequent
calls have no effect.
Returns
- true if this task is scheduled for one-time execution and has
not yet run, or this task is scheduled for repeated execution.
Returns false if the task was scheduled for one-time execution
and has already run, or if the task was never scheduled, or if
the task was already cancelled. (Loosely speaking, this method
returns true if it prevents one or more scheduled
executions from taking place.)
public
abstract
void
run
()
The action to be performed by this timer task.
public
long
scheduledExecutionTime
()
Returns the scheduled execution time of the most recent
actual execution of this task. (If this method is invoked
while task execution is in progress, the return value is the scheduled
execution time of the ongoing task execution.)
This method is typically invoked from within a task's run method, to
determine whether the current execution of the task is sufficiently
timely to warrant performing the scheduled activity:
public void run() {
if (System.currentTimeMillis() - scheduledExecutionTime() >=
MAX_TARDINESS)
return; // Too late; skip this execution.
// Perform the task
}
This method is typically
not used in conjunction with
fixed-delay execution repeating tasks, as their scheduled
execution times are allowed to drift over time, and so are not terribly
significant.
Returns
- the time at which the most recent execution of this task was
scheduled to occur, in the format returned by Date.getTime().
The return value is undefined if the task has yet to commence
its first execution.