Using JAI

[Jennifer Sohl]

I have downloaded JAI so I have the ability to view .tif images in an application. I somehow need to use JAI to create an image preview in a JFileChooser, but I'm not really sure how to go about it. I don't really understand the imaging stuff very well yet, but I'm trying!
This is currently the ImagePreview class used to display images in the JFileChooser (From sun's tutorial):

public class ImageFilePreview extends JComponent
                          implements PropertyChangeListener {
    ImageIcon thumbnail = null;
    File file = null;
 
    public ImageFilePreview(JFileChooser fc) {
        setPreferredSize(new Dimension(500, 500));
        fc.addPropertyChangeListener(this);
    }
 
    public void loadImage() {
        if (file == null) {
            thumbnail = null;
            return;
        }
 
        //Don't use createImageIcon (which is a wrapper for getResource)
        //because the image we're trying to load is probably not one
        //of this program's own resources.
        ImageIcon tmpIcon = new ImageIcon(file.getPath());
        if (tmpIcon != null) {
            if (tmpIcon.getIconWidth() > 500) {
                thumbnail = new ImageIcon(tmpIcon.getImage().
                                          getScaledInstance(500, -1,
                                                      Image.SCALE_DEFAULT));
            } else { //no need to miniaturize
                thumbnail = tmpIcon;
            }
        }
    }
    public void propertyChange(PropertyChangeEvent e) {
        boolean update = false;
        String prop = e.getPropertyName();
 
        //If the directory changed, don't show an image.
        if (JFileChooser.DIRECTORY_CHANGED_PROPERTY.equals(prop)) {
            file = null;
            update = true;
 
        //If a file became selected, find out which one.
        } else if (JFileChooser.SELECTED_FILE_CHANGED_PROPERTY.equals(prop)) {
            file = (File) e.getNewValue();
            update = true;
        }
 
        //Update the preview accordingly.
        if (update) {
            thumbnail = null;
            if (isShowing()) {
                loadImage();
                repaint();
            }
        }
    }
 
    protected void paintComponent(Graphics g) {
        if (thumbnail == null) {
            loadImage();
        }
        if (thumbnail != null) {
            int x = getWidth()/2 - thumbnail.getIconWidth()/2;
            int y = getHeight()/2 - thumbnail.getIconHeight()/2;
 
            if (y < 0) {
                y = 0;
            }
 
            if (x < 5) {
                x = 5;
            }
            thumbnail.paintIcon(this, g, x, y);
        }
    }
}  

It currently only displays .jpg and .gif images. How do I incorporate JAI into this class I already have, so .tif images can be previewed?
(If anyone knows of a good book on the imaging stuff in java, please let me know!)

Thanks for any help!