xletviewjmfexample.java

middleware

/**
 * A JMF example xlet for XleTView.  PLease note that due to the nature of JMF
 * support in XleTView, this example will NOT work on a normal MHP 
 * implementation without a few changes.
 *
 * This is based on an example xlet posted to the XleTView forums by Martin
 * Sveden.  A couple of changes have been made to his original version in
 * order to fix minor bugs, and comments have been added.
 *
 * Thanks to Martin and the rest of the XleTView team for their work in helping 
 * newcomers to the MHP community to get started with an easy way of developing 
 * xlets.  It's appreciated, guys, and not just by the newbies!
 * -- Steve Morris
 */

import java.awt.Component; 
import java.awt.Rectangle; 
import java.io.IOException; 

import javax.media.*; 
import javax.media.protocol.*;
import javax.tv.xlet.*; 
import org.havi.ui.*; 

public class XletviewJMFExample 
	extends HContainer
	implements Xlet, ControllerListener { 
 
	// The URL of the video that we will display.  For XleTView we must use a
	// file:// URL because we don't have a broadcast interface.
	//
	// This will NOT work in a real MHP or OCAP implementation because MHP and
	//  OCAP do not support playing a video from a file.  In a real
	// implementation, this URL should be a dvb:// or ocap:// URL, depending
	// on the platform.
	private static final String VIDEO_URL 
		= "file://d://ch1.avi";
	
	private static final String VIDEO_URL_2 
		= "file://d://ch2.avi";
	
	// Instance variables
	private HScene scene; 
	private XletContext context; 
	private Player player; 
 
	public void initXlet(XletContext ctx)
		throws XletStateChangeException { 

		// Store our XletXontext because we will need it later.
		this.context = context; 

		// Get an HScene so that we can display ourselves.

		// First we get a reference to the HSceneFactory that will create our 
		// HScene.
		HSceneFactory factory = HSceneFactory.getInstance(); 

		// Build a full-screen HSceneTemplate.
		HSceneTemplate hst = new HSceneTemplate();
		hst.setPreference(HSceneTemplate.SCENE_SCREEN_DIMENSION,
		                  new org.havi.ui.HScreenDimension(1, 1),
		                  HSceneTemplate.REQUIRED);
		hst.setPreference(HSceneTemplate.SCENE_SCREEN_LOCATION, 
		                  new org.havi.ui.HScreenPoint(0, 0),
		                  HSceneTemplate.REQUIRED);

		// Now get our HScene.
		scene = factory.getBestScene(hst);
		
		// If we can't get an HScene that meets our needs, die.
		if (scene == null) 
			throw new XletStateChangeException("Can't create HScene");

		// If we have got a suitable HScene, set our size to be the full size of
		// the HScene and add ourselves to it.
		Rectangle rect = scene.getBounds(); 
		setBounds(rect); 

		scene.setVisible(false); 
		scene.add(this); 
	} 
 
	public void startXlet() {  
		// first, create a MediaLocator for the video we want to play.  In a
		// normal MHP or OCAP implementation this would be created from a 
		// dvb:// or ocap:// URL respectively.
		javax.media.MediaLocator locator;

		//Set our scene to be visible.  Later in the Xlet we will put the video 
		// in an HComponent, so we need a visible HScene in which to display it.
		scene.setVisible(true);

		while (true) {
		try { 
			// Create a data source for our locator.  We could create the player
			// directly by calling Manager.createPlayer() with the MediaLocator if we
			// preferred - the effect is the same.
			locator = new javax.media.MediaLocator(VIDEO_URL); 
			DataSource playingDataSource = Manager.createDataSource(locator); 
			// Now create the player
			player = Manager.createPlayer(playingDataSource); 
			
			// Add ourselves as a listener for events from the player
			player.addControllerListener(this); 
			
			// Start the player.  At this point, any video would be played in the 
			// background on a normal MHP or OCAP receiver.
			player.start(); 
			
			System.out.println("sleeping...");
			Thread.sleep(10000);
			
			System.out.println("stopping video 1")
			player.stop();
			
			Thread.sleep(5000);
			System.out.println("deallocating video 1")
			player.deallocate();
			
			Thread.sleep(5000);
			System.out.println("closing video 1")
			player.close();

			Thread.sleep(5000);
			System.out.println("starting video 2")
			locator = new javax.media.MediaLocator(VIDEO_URL_2); 
			playingDataSource = Manager.createDataSource(locator); 
			player = Manager.createPlayer(playingDataSource); 
			player.addControllerListener(this); 
			player.start(); 
			
			System.out.println("started video 2")
			Thread.sleep(10000);
			
		} 
		catch (IOException e) { 
			e.printStackTrace(); 
		} 
		catch (MediaException e) { 
			e.printStackTrace(); 
		} 

		}
		
	} 
 
	public void pauseXlet() { 
		// Pausing ur Xlet should free any scarce resources.  Since the MPEG decoder
		// is usually a scarce resource (but not in XleTView), we will stop our 
		// player and destroy it.
		player.stop();
		player.close();
		player = null;
	} 
 
	public void destroyXlet(boolean unconditional) { 
		// Stop and destroy the player.
		player.stop();
		player.close();
		player = null;

		// Destroy our HScene.  We must remember to do this because the middleware
		// may be storing references to our HScene.  If we do not dispose of the
		// HScene (and any other graphics objects, etc.) then these references will
		// continue to exist, the object may not get garbage collected and we leak
		// memory.
		if (scene != null) { 
			scene.setVisible(false); 
			scene.remove(this); 
			HSceneFactory.getInstance().dispose(scene); 
		} 
		scene = null; 
	} 

	/**
	 * Handle events from the JMF Player.  
	 *
	 * In this case we only care about two events and ignore any others.
	 */
	public void controllerUpdate(ControllerEvent event) { 
		// Print out the event we have received on the debug console.
		System.out.println("" + event); 
		
		// Has the player finished realizing?
		if (event instanceof RealizeCompleteEvent) {
			// Try to display the video in a window (admittedly, a full-screen window)
			Component comp; 
			// Calling getVisualComponent() will convert the player from a
			// 'background player' (which plays its video in the video plane)
			// to a 'component player' (which plays its video in an AWT component).
			// This is a one-way operation, so the only way to go back is to
			// destroy the current player and create a new one.  If the operation 
			// fails, then the player will remain as a background player.
			if ((comp = player.getVisualComponent()) != null) { 
				add(comp); 
				System.out.println("Added " + comp + " as a video component"); 
				
				// Set the size and position (full screen, placed in the top left corner)
				// and draw it.
				comp.setSize(720, 576); 
				setSize(720, 576); 
				validate(); 
				repaint(); 
			} 
		} 
		else if (event instanceof EndOfMediaEvent) { 
			// We've reached the end of the media; rewind and 
			// start over.
			
			// Note that setMediaTime() will NOT work in this way on a real MHP
			// implementation.  The concept of 'media time' has no real meaning in a
			// broadcast environment, and so xlets can only set the media time of
			// audio clips that are played from a file.
			player.setMediaTime(new Time(0)); 
			player.start(); 
		} 
	} 
}