GridImages skeleton

import java.util.HashMap;
import javax.swing.ImageIcon;
import java.awt.image.*;
import java.awt.*;
import java.io.*;
import java.util.List;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.GrayFilter;

/**
 * GridImages represents the images to be used for pieces and backgrounds in
 * a grid game.  GridImages acts like a map between piece names and their
 * corresponding images.  The key values do NOT contain actual filenames.
 * In most cases the plugin author will want to use an enum name as the key.
 *
 * GridImages is a Singleton.
 */
public final class GridImages
{
    /** The name of the directory containing the images */
    public final static String kImageDir = "Images";
    /** The prefix for background images */
    public final static String kBackgroundPrefix = "background";
    /** The prefix for piece images */
    public final static String kPiecePrefix = "piece";
    /** The prefixes for all desired files to be loaded. */
    public final static String[] kImagePrefixes =
    {
        kBackgroundPrefix, kPiecePrefix
    };
    private final String imagePath = kImageDir + System.getProperty(
            "file.separator");

    /** Initialize and return the one allowed instance of this class.
     * The instance contains images loaded from <code>kImageDir</code>,
     * whose names begin with the <code>kImagePrefixes</code>.  For example,
     * if <code>kPiecePrefix</code> contains "piece" then all images whose filenames
     * begin with "piece" will be loaded from <code>kImageDir</code>:
     * piecehidden.jpg, pieceflagged.png, pieceflower.jpg and so on.
     *
     * @param gamePrefix is the folder in which to find <code>kImageDir</code>
     * @return an instance of this class.
     * @post An error message will be displayed if there are no files with
     * the given prefix in the specified directory.  Hint: use FilenameFilter.
     */
    public static GridImages createInstance(String gamePrefix)

    /** Retrieve an image.
     * @param name the name of the desired image (usually the <code>name()</code>
     * of a piece enum)
     * @return ImageIcon the image associated with the specified name
     */
    public ImageIcon getImage(String name)

    /** Constructor is private to defeat instantiation */
    private GridImages(String prefix)

}