package horstmann.ch10_proxy;
import java.awt.Component;
import java.awt.Graphics;

import javax.swing.Icon;
import javax.swing.ImageIcon;

/**
   A proxy for delayed loading of image icons.
 */
public class ImageProxy implements Icon
{
	/**
      Constructs a proxy for delayed loading of an image file.
      @param name the file name
	 */
	public ImageProxy(String name)
	{
		this.name = name;
		image = null;
	}

	public void paintIcon(Component c, Graphics g, int x, int y)
	{
		ensureImageLoaded();
		image.paintIcon(c, g, x, y);
	}

	public int getIconWidth()
	{
		ensureImageLoaded();
		return image.getIconWidth();
	}

	public int getIconHeight()
	{
		ensureImageLoaded();
		return image.getIconHeight();
	}

	/**
      Loads the image if it hasn't been loaded yet. Prints
      a message when the image is loaded.
	 */
	private void ensureImageLoaded()
	{
		if (image == null)
		{
			System.out.println("Loading " + name);
			image = new ImageIcon(name);
		}
	}

	private String name;
	private ImageIcon image;
}