finished

Author: czeigler

src/Application.java

@@ -6,89 +6,102 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-/**
+/**=====================================================================================================================
  * User: chris
  * Date: 3/8/13
  * Time: 4:01 PM
  * CIS 611 Assignment #5
  *
  * The GUI for the calculator application
- */
+ =====================================================================================================================*/
 
-public class Application implements ActionListener {
+public class Application extends JFrame implements ActionListener {
 
     public static final String BUTTON_TEXT_ADD = "Add";
     public static final String BUTTON_TEXT_SUBTRACT = "Subtract";
     public static final String BUTTON_TEXT_MULTIPLY = "Multiply";
     public static final String BUTTON_TEXT_DIVIDE = "Divide";
-    JTextField resultsField;
-    JTextField num1Field;
-    JTextField num2Field;
+    private JTextField resultsField;
+    private JTextField num1Field;
+    private JTextField num2Field;
     private JLabel num1Label;
     private JLabel num2Label;
     private JLabel resultsLabel;
 
-    // the main method for setting up the GUI
+    //==================================================================================================================
+    // the constructor is the main method for setting up the GUI
     public Application() {
 
-        JFrame frame = new JFrame("My Calculator");
-
-        frame.setSize(550,100);
-        frame.setLocationRelativeTo(null);
-        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
-
-
-        doTheLayout(frame);
-        frame.pack();
-        frame.setVisible(true);
+        // call our method to create and add all the controls to the window
+        makeTheObjects();
+        doTheLayout(this);
 
     }
 
+    //==================================================================================================================
     private void doTheLayout(JFrame frame) {
+        // create a panel with the buttons on it the panels allow me to
+        // layout the controls at a more granular level add the panel to the frame
         JPanel buttonsPanel = getButtonsPanel();
+
+        // create a panel with the fields on it
         JPanel fieldsPanel = getFieldsPanel();
+
+        // this layout lets you put components around the outside of the frame
         BorderLayout calculatorLayout = new BorderLayout();
         frame.setLayout(calculatorLayout);
 
+        // the north position is just at the top of the layout
         frame.add(fieldsPanel, BorderLayout.NORTH);
+        // center puts the panel in the frame and allows it to expand to fit the available space
         frame.add(buttonsPanel, BorderLayout.CENTER);
     }
 
+    //==================================================================================================================
     private JPanel getFieldsPanel() {
         JPanel fieldsPanel = new JPanel();
-        FlowLayout gridLayout = new FlowLayout();
-        fieldsPanel.setLayout(gridLayout);
-        makeTheObjects();
+        // create a layout for the fields that will just place them left to right
+        FlowLayout flowLayout = new FlowLayout();
+        fieldsPanel.setLayout(flowLayout);
+
 
+        // add the fields that we created to the panel in the correct order
         fieldsPanel.add(num1Label);
         fieldsPanel.add(num1Field);
         fieldsPanel.add(num2Label);
         fieldsPanel.add(num2Field);
         fieldsPanel.add(resultsLabel);
         fieldsPanel.add(resultsField);
 
-
         return fieldsPanel;
     }
 
+    //==================================================================================================================
+    // create the form controls
     private void makeTheObjects() {
+        // this method creates the labels and the text fields for the input
         num1Label = new JLabel("Number 1:");
         num2Label = new JLabel("Number 2:");
         resultsLabel = new JLabel("Results:");
+        // create and set the sizes of the text fields
         num1Field = new JTextField(5);
         num2Field = new JTextField(5);
+        // create the results field and make it read only
         resultsField = new JTextField(15);
         resultsField.setEditable(false);
     }
 
-
+    //==================================================================================================================
     // create the buttons for the calculator
     private JPanel getButtonsPanel() {
         JPanel numbersPanel = new JPanel();
+
+        // make a layout that is one component high and four wide
         GridLayout gridLayout = new GridLayout(1, 4);
         numbersPanel.setLayout(gridLayout);
 
-
+        // put the buttons in the panel in the order that they should
+        // be displayed left to right
         addCalculatorButton(numbersPanel, BUTTON_TEXT_ADD);
         addCalculatorButton(numbersPanel, BUTTON_TEXT_SUBTRACT);
         addCalculatorButton(numbersPanel, BUTTON_TEXT_MULTIPLY);
@@ -97,20 +110,32 @@ private JPanel getButtonsPanel() {
 
     }
 
+    //==================================================================================================================
+    // create a button and set up the action listener for it
     private void addCalculatorButton(JPanel numbersPanel, String buttonText) {
         JButton button = new JButton(buttonText);
+        // make the first letter of the caption a keyboard shortcut
         button.setMnemonic(buttonText.charAt(0));
+        // the Application class implements ActionListener so add this as
+        // the listener
         button.addActionListener(this);
         numbersPanel.add(button);
     }
 
+    //==================================================================================================================
+    // the action listener will be called when an action on a control that is associated
+    // with the listener takes place
     @Override
     public void actionPerformed(ActionEvent actionEvent) {
 
+        // make sure that the user typed in a valid number for our purposes
         if (validateNumberFields()) {
+
+            // parse the string that's in the text field to a double precision floating point number
             double number1 = Double.parseDouble(num1Field.getText());
             double number2 = Double.parseDouble(num2Field.getText());
 
+            // do the correct operation and display the results in the appropriate field
             if(actionEvent.getActionCommand().equals(BUTTON_TEXT_ADD)) {
                     resultsField.setText(String.valueOf(number1 + number2));
 
@@ -121,28 +146,36 @@ public void actionPerformed(ActionEvent actionEvent) {
                 resultsField.setText(String.valueOf(number1 * number2));
 
             } else if(actionEvent.getActionCommand().equals(BUTTON_TEXT_DIVIDE)) {
+                // we definitely don't want to divide by zero!
                 if(number2 != 0) {
                     resultsField.setText(String.valueOf(number1 / number2));
                 } else {
-                    JOptionPane.showMessageDialog(null, "Number 2 cannot be zero if you are dividing.", "Error", JOptionPane.ERROR_MESSAGE);
+                    JOptionPane.showMessageDialog(null, "Number 2 cannot be zero if you are dividing.", "Error"
+                            , JOptionPane.ERROR_MESSAGE);
 
                 }
 
             }
         }
-
     }
 
+    //==================================================================================================================
+    // use a regular expression to validate that the number is in the correct format.
+    // display an error message if it is not
     private boolean validateNumberFields() {
-        Pattern regexPattern = Pattern.compile("[0-9.]+");
+
+
+        Pattern regexPattern = Pattern.compile("[\\-0-9.]+");
         Matcher matcher = regexPattern.matcher(num1Field.getText());
         if(! matcher.matches()) {
-            JOptionPane.showMessageDialog(null, "Number 1 must be a whole or decimal number.  Do not include any other symbols or punctuation ", "Error", JOptionPane.ERROR_MESSAGE);
+            JOptionPane.showMessageDialog(null, "Number 1 must be a whole or decimal number.  Do not include" +
+                    " any other symbols or punctuation ", "Error", JOptionPane.ERROR_MESSAGE);
             return false;
         }
         matcher = regexPattern.matcher(num2Field.getText());
         if(! matcher.matches()) {
-            JOptionPane.showMessageDialog(null, "Number 2 must be a whole or decimal number.  Do not include any other symbols or punctuation", "Error", JOptionPane.ERROR_MESSAGE);
+            JOptionPane.showMessageDialog(null, "Number 2 must be a whole or decimal number.  Do not include" +
+                    " any other symbols or punctuation", "Error", JOptionPane.ERROR_MESSAGE);
             return false;
         }
         return true;

src/Calculator.java

@@ -1,3 +1,5 @@
+import javax.swing.*;
+
 /**
  * User: chris
  * Date: 3/8/13
@@ -9,10 +11,22 @@
 public class Calculator {
 
     public static void main(String[] args) {
-        Application application = new Application();
 
-    }
+        JFrame f = new Application();
+        // set the desired size for the frame
+        f.setSize(550,120);
+
+        // set the window in relation to nothing - center it
+        f.setLocationRelativeTo(null);
 
+        // what to do with the application when this frame is closed - exit the application
+        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
+        f.setTitle("My Calculator");
 
+        // size the frame so that all the components are the desired size
+        f.pack();
+
+        f.setVisible(true);
+    }
 }