/**	A Book that can be compared to another Book by comparing their isbn
	numbers using the compareTo() function. */
public class ComparableBook extends Book implements Comparable
{
	/**	Constructor. */
	public ComparableBook(String t, String a, String i)
	{
		super(t, a, i);
	}

	/**	Is the current Book less than `other'? 
		Analysis: Time = O(1) */
	public int compareTo(Object other)
	{
		return isbn.compareTo(((Book)other).isbn);
	}

	/**	Is the current Book equal to `other' using isbn for comparison? 
		Analysis: Time = O(1) */
	public boolean equals(Object other)
	{
		return (compareTo(other) == 0);
	}
}