Package com.google.gwt.user.client

Class Timer

java.lang.Object

com.google.gwt.user.client.Timer

public abstract class Timer
extends Object

A simplified, browser-safe timer class. This class serves the same purpose as java.util.Timer, but is simplified because of the single-threaded environment.

To schedule a timer, simply create a subclass of it (overriding run()) and call schedule(int) or scheduleRepeating(int).

NOTE: If you are using a timer to schedule a UI animation, use AnimationScheduler instead. The browser can optimize your animation for maximum performance.

Example

public class TimerExample implements EntryPoint, ClickHandler {

  public void onModuleLoad() {
    Button b = new Button("Click and wait 5 seconds");
    b.addClickHandler(this);

    RootPanel.get().add(b);
  }

  public void onClick(ClickEvent event) {
    // Create a new timer that calls Window.alert().
    Timer t = new Timer() {
      @Override
      public void run() {
        Window.alert("Nifty, eh?");
      }
    };

    // Schedule the timer to run once in 5 seconds.
    t.schedule(5000);
  }
}

Constructor Summary

Constructors

Constructor	Description
Timer()

Method Summary

Modifier and Type	Method	Description
void	cancel()	Cancels this timer.
(package private) final void	fire(int scheduleCancelCounter)
final boolean	isRunning()	Returns true if the timer is running.
abstract void	run()	This method will be called when a timer fires.
void	schedule(int delayMillis)	Schedules a timer to elapse in the future.
void	scheduleRepeating(int periodMillis)	Schedules a timer that elapses repeatedly.

Methods inherited from class java.lang.Object

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

Constructor Details

Timer

public Timer()

Method Details

isRunning

public final boolean isRunning()

Returns true if the timer is running. Timer is running if and only if it is scheduled but it is not expired or cancelled.

cancel

public void cancel()

Cancels this timer. If the timer is not running, this is a no-op.

run

public abstract void run()

This method will be called when a timer fires. Override it to implement the timer's logic.

schedule

public void schedule(int delayMillis)

Schedules a timer to elapse in the future. If the timer is already running then it will be first canceled before re-scheduling.

Parameters:

delayMillis - how long to wait before the timer elapses, in milliseconds

scheduleRepeating

public void scheduleRepeating(int periodMillis)

Schedules a timer that elapses repeatedly. If the timer is already running then it will be first canceled before re-scheduling.

Parameters:

periodMillis - how long to wait before the timer elapses, in milliseconds, between each repetition

fire

final void fire(int scheduleCancelCounter)