/** * Represent a location in a rectangular grid. *  * @author David J. Barnes and Michael Kolling * @version 2006.03.30 */public class Location{    // Row and column positions.    private int row;    private int col;    /**     * Represent a row and column.     * @param row The row.     * @param col The column.     */    public Location(int row, int col)    {        this.row = row;        this.col = col;    }        /**     * Implement content equality.     */    public boolean equals(Object obj)    {        if(obj instanceof Location) {            Location other = (Location) obj;            return row == other.getRow() && col == other.getCol();        }        else {            return false;        }    }        /**     * Return a string of the form row,column     * @return A string representation of the location.     */    public String toString()    {        return row + "," + col;    }        /**     * Use the top 16 bits for the row value and the bottom for     * the column. Except for very big grids, this should give a     * unique hash code for each (row, col) pair.     * @return A hashcode for the location.     */    public int hashCode()    {        return (row << 16) + col;    }        /**     * @return The row.     */    public int getRow()    {        return row;    }        /**     * @return The column.     */    public int getCol()    {        return col;    }}