1 /* CSC 120 Lecture 32
  2  *
  3  * Examples of Object Scope differences
  4  *
  5  */
  6 import java.awt.*;
  7 import java.text.DecimalFormat;
  8 import javax.swing.*;
  9 
 10 public class MUPanel extends JPanel {
 11 
 12     Double tax = 0.07;    
 13     DecimalFormat currency;
 14     
 15 
 16     // constructor method
 17     public MUPanel() {
 18         setLayout(null);
 19         setPreferredSize(new Dimension(800, 600));
 20         setName("CSC 120 Lecture 32:  Scope Examples");
 21         setUp();
 22         setUpGUI();
 23         setBackground(Color.GREEN);
 24         
 25 
 26         currency = new DecimalFormat("#.00");
 27         
 28         Double amtDue = calculateCost(100.00);
 29         System.out.println( "You owe $"
 30                + currency.format(amtDue) + " using a tax rate of "
 31                + tax );
 32         outputArea.append("First version (does not use this.tax in the method):\n");
 33         outputArea.append( "\n  You owe $" + currency.format(amtDue) + " using a tax rate of " + tax + "\n\n\n");
 34         
 35         
 36         
 37         Double amtDue2nd = calculateCost2ndVersion(100.00);
 38         System.out.println( "You owe $"
 39                + currency.format(amtDue2nd) + " using a tax rate of "
 40                + tax );
 41 
 42         outputArea.append("Second version (uses this.tax in the method):\n");
 43         outputArea.append( "\n  You owe $" + currency.format(amtDue2nd) + " using a tax rate of " + tax + "\n\n\n");
 44         
 45         
 46         
 47     } // end of constructor
 48     
 49     
 50     public Double calculateCost(Double beforeTaxAmt) {
 51         Double tax = 0.10;
 52         Double total;
 53         total = beforeTaxAmt + beforeTaxAmt*tax;
 54         return total;
 55     } // end of calculateCost
 56     
 57     
 58     
 59     
 60     public Double calculateCost2ndVersion(Double beforeTaxAmt) {
 61         Double tax = 0.10;
 62         Double total;
 63         total = beforeTaxAmt + beforeTaxAmt*this.tax;
 64         return total;
 65     } // end of calculateCost
 66     
 67     
 68     
 69     
 70     
 71     @Override
 72     public void paintComponent(Graphics g) {
 73         super.paintComponent(g); // This line must be first in this method!
 74     } // end of paintComponent()
 75     
 76     
 77     
 78        
 79     
 80     
 81     
 82     /***********************************************
 83      * Do NOT change or delete anything below here!
 84      ***********************************************/
 85     public void setUp() {
 86         for (Component c: getComponents())
 87             c.setSize(c.getPreferredSize());
 88         JFrame f = new JFrame(getName());
 89         f.setContentPane(this);
 90         f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 91         f.pack();
 92         f.setVisible(true);    
 93     }
 94 
 95     public TextArea outputArea;
 96     
 97     public void setUpGUI() {
 98         outputArea = new TextArea();
 99         outputArea.setBounds(15, 15, 770, 570);
100         outputArea.setFont(new Font("Monospaced", Font.PLAIN, 18));
101         add(outputArea);
102     }
103     
104     public static void main(String args[]){new MUPanel();}
105 
106 } // end of class MUPanel
107