COP 3530
Section U03
package spring09generics;



                                The Triple Generic Class
                                ========================


I. The class


package generics2;

public class Triple < E extends Comparable <? super E>>
{
    // the fields
    private E first;
    private E second;
    private E third;

    /** Creates a new instance of Triple with the parameters item1, item2, item3 */
    public Triple(E item1, E item2, E item3)
    {
        first = item1;
        second = item2;
        third = item3;
    }

    // sort first, second, and third such that the smallest is in first, the in between
    // in second and the largest is in third
    public void sort()
    {
        // if first > second swap them
        if (first.compareTo(second) > 0)
        {
            // swap them
            E temp = first;
            first = second;
            second = temp;
        }

        // if second > third, swap them
        if (second.compareTo(third) > 0)
        {
            // swap them
            E temp = second;
            second = third;
            third = temp;
        }

        // if first > second, swap them
        if (first.compareTo(second) > 0)
        {
            // swap them
            E temp = first;
            first = second;
            second = temp;
            
        }

    }

    // get the first field
    public E getFirst()
    {
        return first;
    }

    // get the second field
    public E getSecond()
    {
        return second;
    }

    // get the third field
    public E getThird()
    {
        return third;
    }

}


II. The driver


package generics2;

public class Generics2 
{
    // use Triple to sort 3 name and 3 integers
    public static void main(String[] args) 
    {
        // sort 3 names
        Triple<String> names = new Triple<String>("Mark","John","Bill");
        names.sort();
        System.out.println("The sorted names are : " + names.getFirst() + ", "
                + names.getSecond() + ", " + names.getThird() + ".");
        // now sort 3 integers
        Triple<Integer> ints = new Triple<>(5, 3, 4);
        ints.sort();
        System.out.println("The sorted integers are: " + ints.getFirst() + ", "
                + ints.getSecond() + ", " + ints.getThird() + ".");
    }
    
}


III. The output:

run:
The sorted names are : Bill, John, Mark.
The sorted integers are: 3, 4, 5.
BUILD SUCCESSFUL (total time: 1 second)