How would I edit this Dorm and Meal Plan Calculator to have one list and one combo box instead of two combo boxes?

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class DormandMealCalculator extends JFrame

{

private JLabel label;

private JPanel dormPanel;

private JPanel selectedDormPanel;

private JComboBox dormBox;

private JTextField selectedDorm;

private JPanel mealPanel;

private JPanel selectedMealPanel;

private JComboBox mealBox;

private JTextField selectedMeal;

private JPanel totalPanel;

private JTextField total;

private String[] dorm =

{

"Allen Hall $" + 1500,

"Pike Hall $ + 1600, "Farthing Hall $" + 1200,

"University Suites $" + 1800};

double[] drate = {1500, 1600, 1200, 1800};

private String[] meal =

{

"7 Meals Per Week $" + 560,

"14 meals per week $" + 1095,

"Unlimited meals $" + 1500};

double [] mrate = {560, 1095, 1500};

public DormandMealCalculator()

{

setTitle("Dorm and Meal Plan Calculator");

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setLayout(new GridLayout(3,2));

buildDormPanel();

buildMealPanel();

buildTotalPanel();

add(dormPanel);

add(mealPanel);

add(totalPanel);

pack();

setVisible(true);

}

private void buildDormPanel()

{

dormPanel = new JPanel();

dormBox = new JComboBox(dorm);

dormBox.addActionListener

(new ComboBoxListener());

dormPanel.add(dormBox);

}

private void buildMealPanel()

{

mealPanel = new JPanel();

mealBox = new JComboBox(meal);

mealBox.addActionListener

(new ComboBoxListener());

mealPanel.add(mealBox);

}

private void buildSelectedDormPanel()

{

selectedDormPanel = new JPanel();

label = new JLabel("Your Dormitory is: ");

selectedDorm = new JTextField(20);

selectedDorm.setEditable(false);

selectedDormPanel.add(label);

selectedDormPanel.add(selectedDorm);

}

private void buildSelectedMealPlanner()

{

selectedMealPanel = new JPanel();

label = new JLabel("Your Meal plan is: ");

selectedMeal = new JTextField(20);

selectedMeal.setEditable(false);

selectedMealPanel.add(label);

selectedMealPanel.add(selectedMeal);

}

private void buildTotalPanel()

{

totalPanel = new JPanel();

label = new JLabel("Your total charges for the semester is: ");

total = new JTextField(15);

totalPanel.add(label);

totalPanel.add(total);

}

private class ComboBoxListener

implements ActionListener

{

public void actionPerformed(ActionEvent e)

{

int dorm;

int meal;

double total1;

String selection1=

(String) dormBox.getSelectedItem();

dorm = dormBox.getSelectedIndex();

String selection2 =

(String) mealBox.getSelectedItem();

meal = mealBox.getSelectedIndex();

total1 = drate[dorm] + mrate[meal];

total.setText("$" + total1);

}

}

public static void main (String[] args)

{

DormandMealCalculator dmc = new DormandMealCalculator();

}

}