Question

Generics Program

In the following problem you will illustrate how we determine the greatest of 3 arguments using a single Generic method. You'll want to restrict the kinds of types that are allowed to be passed to Comparable objects. Create a GUI application which tests a method called maximum by calling the method 3 times; first with 3 ints, then with 3 doubles, and finally with 3 string objects as parameters. Your method maximum will determine the greatest of the 3 comparable objects. Clicking on the Display button will generate output to the JTextArea. You must write a single generic method declaration that can be called with arguments of different types You may simply hard code the data for the arguments when you call method maximum. You may wish to use the Fahrenheit example from module 1 as a guide

Answer 1

PROGRAM CODE:

package GUI;

import java.awt.BorderLayout;

import java.awt.Dimension;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextArea;

public class MaximumThreeGeneric {

   //Generic method for fins the maximum of three values

   public static <T extends Comparable<T>> String maximum(T arg1, T arg2, T arg3)

   {

       String result = "";

       if(arg1.compareTo(arg2) > 0)

       {

           if(arg1.compareTo(arg3) > 0)

               result = arg1.toString();

           else

               result = arg3.toString();

       }

       else if(arg2.compareTo(arg3) > 0)

       {

           if(arg2.compareTo(arg1) > 0)

               result = arg2.toString();

           else result = arg1.toString();

       }

       else result = arg3.toString();

       return result;

   }

  

  

  

   public static void main(String[] args) {

       JFrame frame = new JFrame("Maximum");

       JPanel pane = new JPanel();

       //creating a textarea to display the result

       String result1 = maximum(3, 4, 5);

       String result2 = maximum(6.6, 8.8, 7.7);

       String result3 = maximum("apple", "pear", "orange");

       JTextArea area = new JTextArea(5, 20);

       area.setEditable(false);

      

       //creating a button to handle the displaying part

       JButton display = new JButton("Display");

       display.setSize(100, 30);

       display.addActionListener(new ActionListener() {

          

           @Override

           public void actionPerformed(ActionEvent e) {

               // TODO Auto-generated method stub

               area.setText("Max of 3, 4, 5: " + result1 + "\n");

               area.append("Max of 6.6, 8.8, 7.7: " + result2 + "\n");

               area.append("Max of apple, pear and orange: " + result3);

           }

       });

      

       //settings for the frame

       pane.setLayout(new BorderLayout());

       pane.add(display, BorderLayout.NORTH);

       pane.add(area, BorderLayout.CENTER);

       frame.setContentPane(pane);

       frame.setVisible(true);

       frame.setMinimumSize(new Dimension(400, 400));

       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

       frame.pack();

      

   }

  

}

OUTPUT:

Maximum Display Max of 3, 4, 5: 5 Max of 6.6, 8.8, 7.7: 8.8 Max of apple, pear and orange: pear