Create a compareTo to a Generic Class that Implements Comparable

Question

I have a Generic Class with two type variables, which implements java.lang.Comparable.

public class DoubleKey implements Comparable

        

Answer 1

First way: use hashCodes, like

 public int compareTo(DoubleKey aThat){
     getFirstKey().hashCode() + getSecondKey().hashCode() - aThat.getFirstKey().hashCode() +   aThat.getSecondKey().hashCode();
 }

(you should think more about formula)

Second way: add comparator to constructor

public DoubleKey(K key1, J key2, Comparator cmp){