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Summary: Ctors | Methods | Inherited Methods | [Expand All]

Since: API Level 1

public class

Timer

extends Object

java.lang.Object
↳	java.util.Timer

Class Overview

Timers schedule one-shot or recurring 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:

With the default fixed-period execution, each successive run of a task is scheduled relative to the start time of the previous run, so two runs are never fired closer together in time than the specified period.
With fixed-rate execution, the start time of each successive run of a task is scheduled without regard for when the previous run took place. This may result in a series of bunched-up runs (one launched immediately after another) if delays prevent the timer from starting tasks on time.

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.

Summary

Public Constructors
	Timer(String name, boolean isDaemon) Creates a new named `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(boolean isDaemon) Creates a new `Timer` which may be specified to be run as a daemon thread.
	Timer() Creates a new non-daemon `Timer`.

Public Methods
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, long period) Schedule a task for repeated fixed-delay execution after a specific time has been reached.
void	schedule(TimerTask task, long delay, long period) Schedule a task for repeated fixed-delay execution after a specific delay.
void	schedule(TimerTask task, Date when) Schedule a task for single execution.
void	schedule(TimerTask task, long delay) Schedule a task for single execution after a specified delay.
void	scheduleAtFixedRate(TimerTask task, long delay, long period) Schedule a task for repeated fixed-rate execution after a specific delay has passed.
void	scheduleAtFixedRate(TimerTask task, Date when, long period) Schedule a task for repeated fixed-rate execution after a specific time has been reached.

[Expand]

Inherited Methods

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

Public Constructors

public Timer (String name, boolean isDaemon)

Since: API Level 1

Creates a new named Timer which may be specified to be run as a daemon thread.

Parameters

name	the name of the `Timer`.
isDaemon	true if `Timer`'s thread should be a daemon thread.

Throws

NullPointerException	is `name` is `null`

public Timer (String name)

Since: API Level 1

Creates a new named Timer which does not run as a daemon thread.

Parameters

name	the name of the Timer.

Throws

NullPointerException	is `name` is `null`

public Timer (boolean isDaemon)

Since: API Level 1

Creates a new Timer which may be specified to be run as a daemon thread.

Parameters

isDaemon	`true` if the `Timer`'s thread should be a daemon thread.

public Timer ()

Since: API Level 1

Creates a new non-daemon Timer.

Public Methods

public void cancel ()

Since: API Level 1

Cancels the 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 ()

Since: API Level 1

Removes all canceled tasks from the task queue. If there are no other references on the tasks, then after this call they are free to be garbage collected.

Returns

the number of canceled tasks that were removed from the task queue.

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

Since: API Level 1

Schedule a task for repeated fixed-delay execution after a specific time has been reached.

Parameters

task	the task to schedule.
when	time of first execution.
period	amount of time in milliseconds between subsequent executions.

Throws

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 schedule (TimerTask task, long delay, long period)

Since: API Level 1

Schedule a task for repeated fixed-delay execution after a specific delay.

Parameters

task	the task to schedule.
delay	amount of time in milliseconds before first execution.
period	amount of time in milliseconds between subsequent executions.

Throws

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)

Since: API Level 1

Schedule a task for single execution. If when is less than the current time, it will be scheduled to be executed as soon as possible.

Parameters

task	the task to schedule.
when	time of execution.

Throws

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)

Since: API Level 1

Schedule a task for single execution after a specified delay.

Parameters

task	the task to schedule.
delay	amount of time in milliseconds before execution.

Throws

IllegalArgumentException	if `delay < 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)

Since: API Level 1

Schedule a task for repeated fixed-rate execution after a specific delay has passed.

Parameters

task	the task to schedule.
delay	amount of time in milliseconds before first execution.
period	amount of time in milliseconds between subsequent executions.

Throws

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)

Since: API Level 1

Schedule a task for repeated fixed-rate execution after a specific time has been reached.

Parameters

task	the task to schedule.
when	time of first execution.
period	amount of time in milliseconds between subsequent executions.

Throws

IllegalArgumentException	if `when.getTime() < 0` or `period <= 0`.
IllegalStateException	if the `Timer` has been canceled, or if the task has been scheduled or canceled.

Results

Interfaces

Classes

Enums

Exceptions

Errors

Timer

Class Overview

Summary

Public Constructors

public Timer (String name, boolean isDaemon)

Parameters

Throws

public Timer (String name)

Parameters

Throws

public Timer (boolean isDaemon)

Parameters

public Timer ()

Public Methods

public void cancel ()

public int purge ()

Returns

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

Parameters

Throws

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

Parameters

Throws

public void schedule (TimerTask task, Date when)

Parameters

Throws

public void schedule (TimerTask task, long delay)

Parameters

Throws

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

Parameters

Throws

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

Parameters

Throws