import javax.swing.*;

import java.awt.Dimension;

import java.awt.GridLayout;

import java.awt.event.*;

// Example with implementing multiple listeners -- since this is a lot more

// clean if you have multiple components that requires event listeners

public class BasicJFrameWithMultipleListeners {

JFrame frame;

JPanel myPanel;

JLabel prompt1, prompt2, prompt3, stat;

JTextField grade1, grade2, grade3;

JButton avgButton, minButton, maxButton;

public BasicJFrameWithMultipleListeners () {

frame = new JFrame ("Basic JFrame With Multiple Listeners Example");

frame.setPreferredSize(new Dimension(400, 250));

frame.setLocation(200, 200);

myPanel = new JPanel ();

myPanel.setLayout(new GridLayout (0,2,10,5));

myPanel.setBorder (BorderFactory.createEmptyBorder (10,10,10,10));

prompt1 = new JLabel ("Enter the first grade: ");

grade1 = new JTextField (10);

prompt2 = new JLabel ("Enter the second grade: ");

grade2 = new JTextField (10);

prompt3 = new JLabel ("Enter the third grade: ");

grade3 = new JTextField (10);

avgButton = new JButton ("Average");

avgButton.addActionListener (new AvgListener ());

minButton = new JButton ("Min");

minButton.addActionListener (new MinMaxListener ());

minButton.setActionCommand ("Min");

maxButton = new JButton ("Max");

maxButton.addActionListener (new MinMaxListener ());

maxButton.setActionCommand ("Max");

stat = new JLabel (" ");

stat.setBorder (BorderFactory.createEmptyBorder (10,0,10,10));

myPanel.add (prompt1);

myPanel.add (grade1);

myPanel.add (prompt2);

myPanel.add (grade2);

myPanel.add (prompt3);

myPanel.add (grade3);

myPanel.add (avgButton);

myPanel.add (minButton);

myPanel.add (maxButton);

myPanel.add (stat);

frame.add (myPanel);

frame.pack ();

frame.setVisible (true);

}

class AvgListener implements ActionListener {

public void actionPerformed (ActionEvent event) {

double avgGrade;

String m1 = grade1.getText ();

String m2 = grade2.getText ();

String m3 = grade3.getText ();

avgGrade = Double.parseDouble(m1) + Double.parseDouble (m2) + Double.parseDouble(m3);

avgGrade /= 3;

stat.setText(Double.toString (avgGrade));

}

}

class MinMaxListener implements ActionListener {

public void actionPerformed (ActionEvent event) {

String eventName = event.getActionCommand ();

double minGrade = 999;

double maxGrade = 0;

double [] grades = new double [3];

grades [0] = Double.parseDouble(grade1.getText ());

grades [1] = Double.parseDouble(grade2.getText ());

grades [2] = Double.parseDouble(grade3.getText ());

if (eventName.equals ("Min")) {

for (int i=0; i < 3; i++)

if (minGrade > grades [i])

minGrade = grades [i];

stat.setText(Double.toString(minGrade));

}

else if (eventName.equals ("Max")) {

for (int i=0; i < 3; i++)

if (maxGrade < grades [i])

maxGrade = grades [i];

stat.setText(Double.toString(maxGrade));

}

}

}

public static void main (String [] args){

new BasicJFrameWithMultipleListeners ();

}

}