Question

Java language

(a) Create a class HexEditor with a constructor which creates a 5x10 text area in a Frame. Also add a pull-down menu with a menu item "Load". Copy the class as the answer to this part.

- 10x File Load

(b) Create another class TestHexEditor with a main() method which creates an object anEditor of the class HexEditor and displays the frame in part (a) using setVisible(true). Copy the class as the answer to this part.

(c) Make changes to the class HexEditor so that it implements ActionListener. In the constructor of the class HexEditor, add the current object as the action listener of the "Load" menu item. Write the corresponding method actionPerformed() which displays a dialog box asking for a file name and load content of the file to the text area using FileInputStream. You can assume the file is a byte file and it exists. Copy the changed/added lines and the new method as the answers to this part.

(d) We will use the BorderLayout manager. Modify the constructor to put the text area on the left, add a label containing a space in the middle, add a new text area (with width 20) on the right, and a button at the bottom. The resulting window is showed below (after a file is loaded). Copy the changed/added lines as the answers to this part.

(e) Modify the method actionPerformed() so that when the update button is pressed, a hexidecimal version of the file is displayed on the right, in which each byte is represented by two hexidecimal digits and followed by a space. You can use Integer.toHexString('B') to convert a byte 'B' to a hexidecimal string. A sample window is shown below (where '0A' on the hex window corresponds to a newline character). Copy the changed/added lines as the answers to this part.

(f) In the pull-down menu, add a "Save" menu item so that the original file can be replaced by the content of the text area on the left. You need to modify the method actionPerformed() to achieve this. If no file was loaded but the user directly type something on the left text area, ask for the file name using a dialog box and replace any existing file. Copy the changed/added lines as the answers to this part.

Answer 1

1. Class HexEditor

   import java.awt.*;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileNotFoundException;
   import java.io.IOException;
   
   
   public class HexEditor  extends javax.swing.JFrame implements ActionListener{
       // Variables declaration - do not modify
       private javax.swing.JMenu jMenu1;
       private javax.swing.JMenuBar jMenuBar1;
       private javax.swing.JMenuItem jmItemLoad;
       private javax.swing.JTextArea txtPlainTextData;
       private javax.swing.JTextArea txtHexData;
       private javax.swing.JLabel lblSeparator;
       private javax.swing.JButton btnUpdateHex;
   
       public HexEditor() {
           initComponents();
           jmItemLoad.addActionListener(this);
       }
   
   
       @SuppressWarnings("unchecked")
       // <editor-fold defaultstate="collapsed" desc="Generated Code">
       private void initComponents() {
           this.setSize(450,300);
           txtPlainTextData = new javax.swing.JTextArea();
           txtHexData = new javax.swing.JTextArea();
           jMenuBar1 = new javax.swing.JMenuBar();
           jMenu1 = new javax.swing.JMenu();
           jmItemLoad = new javax.swing.JMenuItem();
           lblSeparator = new javax.swing.JLabel();
           btnUpdateHex = new javax.swing.JButton();
           setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
           setResizable(true);
   
           txtPlainTextData.setColumns(10);
           txtPlainTextData.setRows(5);
           txtHexData.setColumns(20);
           txtHexData.setRows(5);
           lblSeparator.setText(" ");
           jMenu1.setText("File");
           jMenu1.setHorizontalAlignment(javax.swing.SwingConstants.LEFT);
           jMenu1.setHorizontalTextPosition(javax.swing.SwingConstants.LEFT);
   
           jmItemLoad.setText("Load");
           jMenu1.add(jmItemLoad);
           btnUpdateHex.setText("Update hex");
   
           jMenuBar1.add(jMenu1);
   
           setJMenuBar(jMenuBar1);
   
           this.add(txtPlainTextData, BorderLayout.LINE_START);
           this.add(lblSeparator, BorderLayout.CENTER);
           this.add(txtHexData,BorderLayout.LINE_END);
           this.add(btnUpdateHex,BorderLayout.PAGE_END);
   
           pack();
       }
   
   
   
       @Override
       public void actionPerformed(ActionEvent e) {
           NewJDialog getFileDialog = new NewJDialog(this, true);
           fileName = getFileDialog.showDialog();
           // File reading
           File file = new File(fileName);
           FileInputStream fStream = null;
           StringBuffer fileData = new StringBuffer("");
           StringBuffer hexData = new StringBuffer("");
           int ch;
           try
           {
               fStream = new FileInputStream(file);
               while((ch=fStream.read()) != -1)
               {
                   fileData.append((char)ch);
                   hexData.append(String.format("%02X",ch)+" ");
               }
               fStream.close();
           } catch (FileNotFoundException ex) {
               ex.printStackTrace();
           } catch (IOException ex) {
               ex.printStackTrace();
           }
           // Load data to text area
           this.txtPlainTextData.setText(fileData.toString());
           this.txtHexData.setText(hexData.toString());
       }
   
       private String fileName;
   }
   

2. Class TestHexEditor

   public class TestHexEditor {
       public static void main(String[] args) {
           HexEditor hexEditor = new HexEditor();
           hexEditor.setVisible(true);
       }
   }
   

3. Dialog Box Class

   import javax.swing.border.Border;
   import java.awt.*;
   
   public class NewJDialog extends javax.swing.JDialog {
   
   
       public NewJDialog(java.awt.Frame parent, boolean modal) {
           super(parent, modal);
           initComponents();
       }
   
   
       @SuppressWarnings("unchecked")
   
       private void initComponents() {
           this.setSize(300,200);
           this.setTitle("Load File");
   
           jLabel1 = new javax.swing.JLabel();
           jtxtFile = new javax.swing.JTextField();
           jbtnLoadFile = new javax.swing.JButton();
           setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
           setResizable(false);
           jtxtFile.setColumns(30);
           jtxtFile.setText("Byte File Path");
           jLabel1.setText("Enter a file to load");
   
           jbtnLoadFile.setText("Load");
           jbtnLoadFile.addActionListener(new java.awt.event.ActionListener() {
               public void actionPerformed(java.awt.event.ActionEvent evt) {
                   fileName = jtxtFile.getText();
                   dispose();
               }
           });
           this.add(jLabel1, BorderLayout.PAGE_START);
           this.add(jtxtFile,BorderLayout.CENTER);
           this.add(jbtnLoadFile,BorderLayout.LINE_END);
   
   
           pack();
       }
       String showDialog()
       {
           setVisible(true);
           return fileName;
       }
       private javax.swing.JButton jbtnLoadFile;
       private javax.swing.JLabel jLabel1;
       private javax.swing.JTextField jtxtFile;
       private String fileName;
   }
   
   

Note: I haven't added update logic in this. You will have to do that your own. Let me know if you face any issues with above class.

when you provide file name, provide fully qualified path

Screen shots

$wNbGGDkkZGlRQAAAABJRU5ErkJggg==$