MainWindow.java

package javanotepad;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JOptionPane;

public class MainWindow extends javax.swing.JFrame {
    String contents;
    Clipboard clipboard = getToolkit().getSystemClipboard();
    File openFile;
    public MainWindow() {
        initComponents();
        setLocationRelativeTo(null);
    }
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jFileChooser1 = new javax.swing.JFileChooser();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();
        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        openMenu = new javax.swing.JMenuItem();
        saveMenu = new javax.swing.JMenuItem();
        saveAsMenu = new javax.swing.JMenuItem();
        exitMenu = new javax.swing.JMenuItem();
        jMenu2 = new javax.swing.JMenu();
        cut = new javax.swing.JMenuItem();
        copy = new javax.swing.JMenuItem();
        paste = new javax.swing.JMenuItem();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Java Notepad");

        jTextArea1.setColumns(20);
        jTextArea1.setRows(5);
        jScrollPane1.setViewportView(jTextArea1);

        jMenu1.setText("File");

        openMenu.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_O, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        openMenu.setText("Open");
        openMenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                openMenuActionPerformed(evt);
            }
        });
        jMenu1.add(openMenu);

        saveMenu.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_S, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        saveMenu.setText("Save");
        saveMenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                saveMenuActionPerformed(evt);
            }
        });
        jMenu1.add(saveMenu);

        saveAsMenu.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_W, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        saveAsMenu.setText("Save As");
        saveAsMenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                saveAsMenuActionPerformed(evt);
            }
        });
        jMenu1.add(saveAsMenu);

        exitMenu.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_E, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        exitMenu.setText("Exit");
        exitMenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                exitMenuActionPerformed(evt);
            }
        });
        jMenu1.add(exitMenu);

        jMenuBar1.add(jMenu1);

        jMenu2.setText("Edit");

        cut.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_X, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        cut.setText("Cut");
        cut.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                cutActionPerformed(evt);
            }
        });
        jMenu2.add(cut);

        copy.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_C, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        copy.setText("Copy");
        copy.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                copyActionPerformed(evt);
            }
        });
        jMenu2.add(copy);

        paste.setAccelerator(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_V, java.awt.event.InputEvent.CTRL_DOWN_MASK));
        paste.setText("Paste");
        paste.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                pasteActionPerformed(evt);
            }
        });
        jMenu2.add(paste);

        jMenuBar1.add(jMenu2);

        setJMenuBar(jMenuBar1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 763, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 448, Short.MAX_VALUE)
        );

        pack();
    }// </editor-fold>                        

    private void openMenuActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        jFileChooser1.showOpenDialog(null);
        openFile = jFileChooser1.getSelectedFile();
        System.out.println(openFile.getAbsolutePath());
        
        try {
            RandomAccessFile f = new RandomAccessFile(openFile,"r");
            long size = openFile.length();
            contents = "";
            while(true)
            {
             String s = null;
             
                try {
                    s = f.readLine();
                } catch (IOException ex) {
                    Logger.getLogger(MainWindow.class.getName()).log(Level.SEVERE, null, ex);
                }
             
             if(s==null)
             {
                break;
             }
             contents += s + "\n"; 
            }
            jTextArea1.setText(contents);
            this.setTitle(this.getTitle()+" : "+ openFile.getName());
            
        } catch (FileNotFoundException ex) {
            Logger.getLogger(MainWindow.class.getName()).log(Level.SEVERE, null, ex);
        }
    }                                        

    private void saveMenuActionPerformed(java.awt.event.ActionEvent evt) {                                         
          
        if(openFile==null)
        {
            System.out.println("File Does Not Exist....");
            jFileChooser1.showSaveDialog(null);
            openFile = jFileChooser1.getSelectedFile();
            System.out.println("Name Of File Should Be Saved With " + openFile);
            try {
                FileWriter fw = new FileWriter(openFile);
                contents = jTextArea1.getText();
                fw.write(contents);
                this.setTitle(this.getTitle()+" : "+ openFile.getName());
                fw.close();
            } catch (IOException ex) {
                Logger.getLogger(MainWindow.class.getName()).log(Level.SEVERE, null, ex);
            }
            
        }
        else
            {
                 FileWriter fw;
            try {
                fw = new FileWriter(openFile);
                contents = jTextArea1.getText();
                fw.write(contents);
                fw.close();
            } catch (IOException ex) {
                Logger.getLogger(MainWindow.class.getName()).log(Level.SEVERE, null, ex);
            }
            }
    }                                        

    private void saveAsMenuActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
            jFileChooser1.showSaveDialog(null);
            File tempFile = jFileChooser1.getSelectedFile();
         
            try {
                FileWriter fw = new FileWriter(tempFile);
                contents = jTextArea1.getText();
                fw.write(contents);
                fw.close();
            } catch (IOException ex) {
                Logger.getLogger(MainWindow.class.getName()).log(Level.SEVERE, null, ex);
            }
    }                                          

    private void exitMenuActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        contents = jTextArea1.getText();
        if(openFile==null)
        {
         int choice = JOptionPane.showConfirmDialog(rootPane,"Do You Want To Save Yout File!!");
         System.out.println(choice);
         if(choice==1)
         {
           System.exit(0);
         }
         else if(choice==0 && contents != null)
         {
            jFileChooser1.showSaveDialog(null);
            File tempFile = jFileChooser1.getSelectedFile();
            try {
                FileWriter fw = new FileWriter(tempFile);
                contents = jTextArea1.getText();
                fw.write(contents);
                fw.close();
            } catch (IOException ex) {
                Logger.getLogger(MainWindow.class.getName()).log(Level.SEVERE, null, ex);
            }
            System.exit(0);
            
         }
        }
    }                                        

    private void cutActionPerformed(java.awt.event.ActionEvent evt) {                                    
        String cutString = jTextArea1.getSelectedText();
        StringSelection cutSelection = new StringSelection(cutString); 
        clipboard.setContents(cutSelection, cutSelection);
        jTextArea1.replaceRange("", jTextArea1.getSelectionStart(), jTextArea1.getSelectionEnd());
    }                                   

    private void copyActionPerformed(java.awt.event.ActionEvent evt) {                                     
        String copyText = jTextArea1.getSelectedText();
        StringSelection copySelection = new StringSelection(copyText);
        clipboard.setContents(copySelection, copySelection);
    }                                    

    private void pasteActionPerformed(java.awt.event.ActionEvent evt) {                                      
        try {
             Transferable pasteText = clipboard.getContents(jTextArea1);
             String se1 = (String) pasteText.getTransferData(DataFlavor.stringFlavor);
             jTextArea1.replaceRange(se1, jTextArea1.getSelectionStart(), jTextArea1.getSelectionEnd());
        } catch (Exception e) {
            System.out.println("Errrrrror :( ");
        }
    }                                     

    public static void main(String args[]) {
        
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new MainWindow().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JMenuItem copy;
    private javax.swing.JMenuItem cut;
    private javax.swing.JMenuItem exitMenu;
    private javax.swing.JFileChooser jFileChooser1;
    private javax.swing.JMenu jMenu1;
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenuBar jMenuBar1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea jTextArea1;
    private javax.swing.JMenuItem openMenu;
    private javax.swing.JMenuItem paste;
    private javax.swing.JMenuItem saveAsMenu;
    private javax.swing.JMenuItem saveMenu;
    // End of variables declaration                   
}