効率の良い描画方法とは？

import java.awt.*;
import java.awt.image.*;
import java.awt.geom.*;
import java.awt.event.*;

public class MyApp {
    public static void main(String[] inArgs) {
        final Frame f = new Frame();
		
		Panel panel = new Panel() {
			public void update(Graphics g) {
				paint(g);
			}
		};
		
		f.add(panel);
		
		panel.setLayout(new GridLayout(2, 1));
		panel.add(new MyPanel("No. 1"));
		panel.add(new MyPanel("No. 2"));
		
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
		
        f.pack();
        f.show();
    }
}

class MyPanel extends Component {
    private static final Font sFont = new Font("Serif", Font.BOLD, 32);

    private final String mText;
    private Rectangle mBounds;
    private Image mOffImage;
	private Graphics mOffGraphics;
	private int mOffsetX = 0;
	private int mOffsetY;
	private Object mLock = new Object();
	private boolean mModified;
	
    public MyPanel(String text) {
        mText = text;

		addFocusListener(new FocusHandler());
		addMouseListener(new MouseHandler());
        
        setFont(sFont);
        FontMetrics fm = getFontMetrics(sFont);
        mOffsetY = fm.getAscent();
        
        Rectangle2D aBounds = fm.getStringBounds(mText, getGraphics());
        mBounds = new Rectangle((int)aBounds.getX(), (int)aBounds.getY(), (int)aBounds.getWidth(), (int)aBounds.getHeight());
		mBounds.translate(0, mOffsetY);
		
        setBounds(mBounds);
        
        setModified(true);
    }
		
	public Dimension getPreferredSize() {
		return new Dimension(mBounds.width, mBounds.height);
	}
	
    public void paint(Graphics g) {
    	if (null == mOffImage) {
    		mOffImage = createImage(mBounds.width, mBounds.height);
	        if (null == mOffImage) {
	      		mOffImage = new BufferedImage(mBounds.width, mBounds.height, BufferedImage.TYPE_INT_RGB);
	      	}
  			mOffGraphics = mOffImage.getGraphics();
    	}
    	
    	synchronized(mLock) {
    		if (isModified()) {
	    		mOffGraphics.setColor(Color.white);
	    		mOffGraphics.fillRect(mBounds.x, mBounds.y, mBounds.width, mBounds.height);
	    		mOffGraphics.setColor(Color.black);
       			mOffGraphics.drawString(mText, mOffsetX, mOffsetY);
	        }
	        
	        g.drawImage(mOffImage, 0, 0, this);
	        
	        setModified(false);
	    }
    }

    private boolean isModified() {
    	return mModified;
    }
    
    private void setModified(final boolean inModified) {
    	mModified = inModified;
    }
    
    private class FocusHandler implements FocusListener {
    	private AnimateRunner mRunner;
    	
    	public void focusGained(FocusEvent inEvent) {
    		System.out.println(MyPanel.this.getClass() + " : " + mText + " (gained)");
    		mRunner = new AnimateRunner();
    		new Thread(mRunner, "animate").start();
    	}
    	
    	public void focusLost(FocusEvent inEvent) {
    		System.out.println(MyPanel.this.getClass() + " : " + mText + " (lost)");
    		mRunner.stop();
    	}
    }
	
	private class AnimateRunner implements Runnable {
		private boolean mStoped = false;
		
		public void run() {
			synchronized(mLock) {
				while(! isStoped() || mOffsetX != 0) {
					long aStartTime = System.currentTimeMillis();
					
					try {
						// Thread.sleep()がmonitorの所有権を離さないって書かれていたので、
						// wait()で指定した時間待ってみるようにした。
						long aTime = 0;
						do {
							mLock.wait(1);
							aTime = System.currentTimeMillis();
						}
						while (aTime - aStartTime < 30);
				
						mOffsetX = mBounds.width > mOffsetX ? ++mOffsetX : -mBounds.width;
						setModified(true);
						repaint(mBounds.x, mBounds.y, mBounds.width, mBounds.height);
					}
					catch (InterruptedException e) {
					}
				}
			}
		}
		
		synchronized void stop() {
			mStoped = true;
		}
		
		synchronized boolean isStoped() {
			return mStoped;
		}
	}
	
	private class MouseHandler implements MouseListener {
		public void mousePressed(MouseEvent inEvent) {
			FocusEvent aEvent = new FocusEvent(MyPanel.this, FocusEvent.FOCUS_GAINED);
			Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(aEvent);
		}
		
		public void mouseClicked(MouseEvent inEvent) {}
		public void mouseReleased(MouseEvent inEvent) {}
		public void mouseEntered(MouseEvent inEvent) {}
		public void mouseExited(MouseEvent inEvent) {}
	}
}

package test;



import java.awt.*;

import java.awt.event.*;



class MeApp

{

    public static void main(String[] args)

    {

        final MeFrame f = new MeFrame();



        f.addWindowListener(new WindowAdapter()

        {

            public void windowClosing(WindowEvent e)

            {

                System.exit(0);

            }

        });



        f.pack();

        f.show();

    }

}



class MeFrame extends Frame

{

    public MeFrame()

    {

        setLayout(new GridLayout(2, 5, 5, 5));



        for (int i = 0; i < 10; ++i)

        {

            add(new MePanel("Panel#" + i));

        }

    }

}



class MePanel extends Component

{

    private static final Font _font = new Font("Serif", Font.BOLD, 20);



    private final Image _image1;

    private final Image _image2;

    private final String _text;



    private Image _currentImage;

    private String _currentText;



    public MePanel(String text)

    {

        enableEvents(AWTEvent.MOUSE_EVENT_MASK | AWTEvent.FOCUS_EVENT_MASK);



        _text = text;



        _image1 =

            Toolkit.getDefaultToolkit().createImage(

                getClass().getResource("1.jpg"));



        _image2 =

            Toolkit.getDefaultToolkit().createImage(

                getClass().getResource("2.jpg"));



        final MediaTracker tracker = new MediaTracker(this);

        tracker.addImage(_image1, 0);

        tracker.addImage(_image2, 0);



        try

        {

            tracker.waitForID(0);

        }

        catch (InterruptedException e)

        {

            throw new Error(e.getMessage());

        }



        handleFocus(false);

    }



    public Dimension getPreferredSize()

    {

        return new Dimension(94, 100);

    }



    public void paint(Graphics g)

    {

        g.setFont(_font);

        g.drawImage(_currentImage, 0, 0, 94, 100, null);

        g.drawString(_currentText, 15, 50);

    }



    private void handleFocus(boolean value)

    {

        if (value) // focus gained

        {

            _currentImage = _image2;

            _currentText = "Focus";

        }

        else // focus lost

        {

            _currentImage = _image1;

            _currentText = _text;

        }



        repaint();

    }



    /////////////////////////////////

    // focus



    public boolean isFocusTraversable() // after 1.4 deprecated (replace by isFocusable())

    {

        return true;

    }



    protected void processMouseEvent(MouseEvent e)

    {

        if (e.getID() == MouseEvent.MOUSE_PRESSED)

        {

            requestFocus();

        }



        super.processMouseEvent(e);

    }



    protected void processFocusEvent(FocusEvent e)

    {

        switch (e.getID())

        {

            case FocusEvent.FOCUS_GAINED:

                handleFocus(true);

                break;

            case FocusEvent.FOCUS_LOST:

                handleFocus(false);

                break;

        }

        

        super.processFocusEvent(e);

    }

}