File	Doc	Category	Size	Date	Package
TimerTask.java	API Doc	Java SE 5 API	4847	Fri Aug 26 14:57:24 BST 2005	java.util

TimerTask

• java.lang.Object

Fields Summary
final Object	lock This object is used to control access to the TimerTask internals.
int	state The state of this task, chosen from the constants below.
static final int	VIRGIN This task has not yet been scheduled.
static final int	SCHEDULED This task is scheduled for execution. If it is a non-repeating task, it has not yet been executed.
static final int	EXECUTED This non-repeating task has already executed (or is currently executing) and has not been cancelled.
static final int	CANCELLED This task has been cancelled (with a call to TimerTask.cancel).
long	nextExecutionTime Next execution time for this task in the format returned by System.currentTimeMillis, assuming this task is scheduled for execution. For repeating tasks, this field is updated prior to each task execution.
long	period Period in milliseconds for repeating tasks. A positive value indicates fixed-rate execution. A negative value indicates fixed-delay execution. A value of 0 indicates a non-repeating task.

Constructors Summary
protected TimerTask() Creates a new timer task.

Methods Summary
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. return 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.) synchronized(lock) { boolean result = (state == SCHEDULED); state = CANCELLED; return result; }
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. return 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. see Date#getTime() synchronized(lock) { return (period < 0 ? nextExecutionTime + period : nextExecutionTime - period); }