Timer Template : Timer « J2ME « Java

1. Java
2. J2ME
3. Timer

Timer Template

/*--------------------------------------------------
* TimerTemplate.java
*
* Test all six Timer scheduling options
*
* Example from the book:     Core J2ME Technology
* Copyright John W. Muchow   http://www.CoreJ2ME.com
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import java.util.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class TimerTemplate extends MIDlet implements CommandListener
{
  private Display display;      // Our display
  private Form fmMain;         // Main form
  private Command cmExit;      // Exit midlet
  private Command cmStop;      // Stop the timer
  private Timer tm;          // Timer
  private TestTimerTask tt;       // Task
  private int count = 0;        // How many times has task run

  public TimerTemplate()
  {
    display = Display.getDisplay(this);

    // Create main form
    fmMain = new Form("Timer Test");
    fmMain.append("waiting...\n");

    // Create commands and add to form
    cmExit = new Command("Exit", Command.EXIT, 1);
    cmStop= new Command("Stop", Command.STOP, 2);
    fmMain.addCommand(cmExit);
    fmMain.addCommand(cmStop);
    fmMain.setCommandListener(this);
    
    //------------------------------------------------------
    // Option #1 - One time task with delayed start
    // Create a timer that will go off in 5 seconds
    //------------------------------------------------------
    tm = new Timer();
    tt = new TestTimerTask();
    tm.schedule(tt,5000);    

    //------------------------------------------------------
    // Option #2 - Fixed-delay repeating task with delayed start
    // Create a timer that will go off in 5 seconds
    // Repeating every 3 seconds
    //------------------------------------------------------
//    tm = new Timer();
//    tt = new TestTimerTask();
//    tm.schedule(tt,5000, 3000);    

    //------------------------------------------------------
    // Option #3 - Fixed-rate repeating task with delayed start
    // Create a timer that will go off in 5 seconds
    // Repeating every 3 seconds
    //------------------------------------------------------
//    timer = new Timer();
//    tt = new TestTimerTask();
//    timer.scheduleAtFixedRate(tt,5000, 3000);    

    //------------------------------------------------------
    // Option #4 - One time task at specified date
    // Create timer that starts at current date
    //------------------------------------------------------
//    timer = new Timer();
//    tt = new TestTimerTask();
//    timer.schedule(tt, new Date());    

    //------------------------------------------------------
    // Option #5 - Fixed-delay repeating task starting 
    //             at a specified date
    // Create timer that starts at current date
    // Repeating every 3 seconds
    //------------------------------------------------------
//    timer = new Timer();
//    tt = new TestTimerTask();
//    timer.schedule(tt, new Date(), 3000);    

    //------------------------------------------------------
    // Option #6 - Fixed-rate repeating task starting
    //             at a specified date
    // Create timer that starts at current date
    // Repeating every 3 seconds
    //------------------------------------------------------
//    timer = new Timer();
//    tt = new TestTimerTask();
//    timer.scheduleAtFixedRate(tt, new Date(), 3000);    
  }

  /*--------------------------------------------------
  * Show the main Form
  *-------------------------------------------------*/
  public void startApp ()
  {
    display.setCurrent(fmMain);
  }

  /*--------------------------------------------------
  * Shutting down. Cleanup all we created
  *-------------------------------------------------*/
  public void destroyApp (boolean unconditional)
  {
  }

  /*--------------------------------------------------
  * No pause code necessary
  *-------------------------------------------------*/
  public void pauseApp ()
  { }

  /*--------------------------------------------------
  * Process events for the main form
  *-------------------------------------------------*/
  public void commandAction(Command c, Displayable d)
  {
    if (c == cmStop)
    {
      tm.cancel();
    }
    else if (c == cmExit)
    {
      destroyApp(false);
      notifyDestroyed();
    }
  }

  /*--------------------------------------------------
  * TestTimerTask Class - Run the task
  *-------------------------------------------------*/  
  private class TestTimerTask extends TimerTask
  {
    public final void run()
    {
      fmMain.append("run count: " + ++count + "\n");
    }
  }
}



           
       

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