How to keep formatting while reading files

[Hunter McMillen]

I'm trying to read a .java file into a JTextArea and no matter what method I use to read in the file the formatting is never preserved. The actual code is ok but the comments always get messed up. Here are my attempts.

Scanner:

   	//reads an input file and displays it in the text area
      public void readFileData(File file)
      {
         Scanner fileScanner = null;
            	
         try
         {
            fileScanner = new Scanner(file);
				while(fileScanner.hasNextLine())
				{
					String line = fileScanner.nextLine();
					
					//output is a JTextArea
					output.append(line + newline);
				}
         	
         }
            catch(FileNotFoundException fnfe)
            {
               System.err.println(fnfe.getMessage());
            }
      }

Scanner reading the full text at once:

   	//reads an input file and displays it in the text area
      public void readFileData(File file)
      {
         Scanner fileScanner = null;
            	
         try
         {
            fileScanner = new Scanner(file);

            fileScanner.useDelimiter("\\Z");
            String fullText = fileScanner.next(); 
         	
         	//print to text area
            output.append(fullText + newline);
         	
         }
            catch(FileNotFoundException fnfe)
            {
               System.err.println(fnfe.getMessage());
            }
      }

BufferedReader:

  	//reads an input file and displays it in the text area
      public void readFileData(File file)
      {
         //Scanner fileScanner = null;
            	
         try
         {
            BufferedReader reader = new BufferedReader(new InputStreamReader(file));
         	
            String line = "";
            while((line = reader.readLine()) != null)
            {
               output.append(line + newline);
            }        	
         }

Is there anyway to keep the formatting the same??

PS - also posted at http://stackoverflow.com/questions/6157294/how-to-keep-formatting-while-reading-files

Hunter

[Carey Brown]

Use a fixed width font.

[Hunter McMillen]

Formatting marks exist regardless of the type of font I am using.

Hunter

[Paul Clapham]

"Messed up"?

"Formatting marks"?

I think we need a better description of the problem. I can't tell from those phrases what the problem is. Can you show us an example?

By the way I wouldn't have written any of that code. Here's the code I would have written:

output.read(new FileReader(file), null);

[Hunter McMillen]

Sure, I have a .java that looks like this with comments organized the way I want them:

   import java.awt.*;
   import java.awt.event.*;
   import javax.swing.*;
	
   import java.io.*;
   import java.util.*;
	
   public class JTextEditor implements ActionListener
   {
      private JTextArea output;
      private JScrollPane scrollPane;
      private final String newline = "\n";
      private boolean saved  = false;
      private boolean opened = false;
      private boolean isNew  = false;
		private File currentFile;
		
   	
   	/**
   	 * Creates and configures the JMenuBar 
   	 * object for the JText editor
   	 *
   	 * @return The customized JMenuBar
   	 */
      public JMenuBar createMenuBar() 
      {
         JMenuBar menuBar;
         JMenu fileMenu, menu, submenu;
         JMenuItem newMenuItem, openMenuItem, saveMenuItem, exitMenuItem;
      
        //Create the menu bar.
         menuBar = new JMenuBar();
      
        //Build the File menu.
         fileMenu = new JMenu("File");
         fileMenu.setMnemonic(KeyEvent.VK_F);
         fileMenu.getAccessibleContext().setAccessibleDescription(
                "This is the File menu, users can create, open, " + 
            	 "and save documents, as well as exit the program");
         menuBar.add(fileMenu);
      
        //create the menu items for the fileMenu
         fileMenu.add(createMenuItem("New.." ,    "Lets users create a new document", true));
         fileMenu.add(createMenuItem("Open..",    "Lets users open a document"      , true));
         fileMenu.add(createMenuItem("Save..",    "Lets users save a document"      , true));
         fileMenu.add(createMenuItem("Save As..", "Lets users save a document"      , true));	
         fileMenu.add(createMenuItem("Exit..",    "Lets users exit the program"     , true));
      	      
         return menuBar;
      }
   	
   	/**
   	 * Creates a new JMenuItem object
   	 * 
   	 * @param name			    The name of the JMenuItem
   	 * @param description		The description of the JMenuItem
   	 * @param actionListener	Whether or not this JMenuItem will need to register an
   	 *							ActionListener (yes, most of the time)
   	 * @return 					A new JMenuItem object
   	 */
      public JMenuItem createMenuItem(String name, String description, boolean actionListener)
      {
         JMenuItem menuItem = new JMenuItem(name);
         menuItem.getAccessibleContext().setAccessibleDescription(description);
      	
         if(actionListener)
            menuItem.addActionListener(this);
      		
         return menuItem;
      }
   	
      public void openFile()
      {
         File			 file;
         JFileChooser fc = new JFileChooser();
      	
         int returnVal = 0; 
      	
      	//prompt the user with the open file dialog
         returnVal = fc.showOpenDialog(output);
      	
         if(returnVal == JFileChooser.APPROVE_OPTION) //user selected and file and hit 'open'
         {
         	//store the file
            currentFile = file = fc.getSelectedFile();
            JOptionPane.showMessageDialog(null, "Opening " + file.getName() + ".");
            readFileData(file);
            opened = true;
         }
         else
         {
            JOptionPane.showMessageDialog(null, "Open command cancelled by user.");
         }
      
      }
   	
   	//reads an input file and displays it in the text area
      public void readFileData(File file)
      {
         Scanner fileScanner = null;
            	
         try
         {
            fileScanner = new Scanner(file);
            while(fileScanner.hasNextLine())
            {
               String line = fileScanner.nextLine();
                     	
               //output is a JTextArea
               output.append(line + newline);
            }       	
         }
            catch(FileNotFoundException fnfe)
            {
               System.err.println(fnfe.getMessage());
            }
      }
   	
      public void writeFileData(File directory, File file)
      {
         BufferedWriter writer;
      	BufferedReader	reader;
			String line = "";
			
         try
         {
				reader = new BufferedReader(new InputStreamReader(new FileInputStream(currentFile)));
            writer = new BufferedWriter(new FileWriter(file));
				System.out.println(file);
				while((line = reader.readLine()) != null)
				{
					writer.write(line);
					writer.newLine();
				}
         	
         }       	
            catch(FileNotFoundException fnfe)
            {
               System.err.println(fnfe.getMessage());
            }
            catch(IOException ioe)
            {
               System.err.println(ioe.getMessage());
            }
      	
         JOptionPane.showMessageDialog(null, "Writing " + file.getName() + " to " + directory); 
      	
      }
   	
      public void saveFile()
      {
         File file;
         File directory;
         JFileChooser fc = new JFileChooser();
         int returnVal = 0;
      	
         if(opened)
         {
            returnVal = fc.showSaveDialog(output);
         	
            if(returnVal == JFileChooser.APPROVE_OPTION)
            {
            	//get the file the user selected to save
               file = fc.getSelectedFile();
               directory = fc.getCurrentDirectory();
               JOptionPane.showMessageDialog(null, "Saving " + file.getName() + ".");
               writeFileData(directory, file);
            }
            else
            {
               JOptionPane.showMessageDialog(null, "Save command cancelled by user.");
            }
         }
         else if(isNew)
         {
         	//saveFileAs();
         }
         else
         {
            JOptionPane.showMessageDialog(null, "You must create or open a document before saving.");
         }
      }
   
      public Container createContentPane() 
      {
        //Create the content-pane-to-be.
         JPanel contentPane = new JPanel(new BorderLayout());
         contentPane.setOpaque(true);
      
        //Create a scrolled text area.
         output = new JTextArea(5, 30);
         //output = new JTextPane();
         output.setFont(new Font("Monospaced", Font.PLAIN, 12));
         output.setEditable(false);
         scrollPane = new JScrollPane(output);
      
        //Add the text area to the content pane.
         contentPane.add(scrollPane, BorderLayout.CENTER);
      
         return contentPane;
      }
   	
      public void actionPerformed(ActionEvent ae) 
      {
         String command = ae.getActionCommand();
      
         String s = " command: " + command;
         JOptionPane.showMessageDialog(null, s);
         output.setCaretPosition(output.getDocument().getLength());
      	
         if(command.equals("New..")) //the New file option was selected
         {
            output.setEditable(true);
         	//createNewFile();
            isNew = true;
         }
         else if(command.equals("Open.."))//the Open file option was selected
         {
            output.setEditable(true);
            openFile();
         }
         else if(command.equals("Save.."))//the Save file option was selected
         {
            saveFile();
         }
         else if(command.equals("Save As.."))//the Save file option was selected
         {
         	//saveFileAs();
         }
         else if(command.equals("Exit.."))//the Exit program option was selected
         {
            String answer = "";
            if(opened && !saved)
            {
               answer = JOptionPane.showInputDialog(null, 
                  "You have not saved changes to this file, would you like to save your changes?");
            	
            	//if the user wants to save, call the save file method
               if(answer.equalsIgnoreCase("y") || answer.equalsIgnoreCase("yes"))
                  saveFile();
            }
            System.exit(0);
         }
      }   	
   	
   	// Returns just the class name -- no package info.
      protected String getClassName(Object o) 
      {
         String classString = o.getClass().getName();
         int dotIndex       = classString.lastIndexOf(".");
         return classString.substring(dotIndex+1);
      }
   
    /** Returns an ImageIcon, or null if the path was invalid. */
      protected static ImageIcon createImageIcon(String path) 
      {
         java.net.URL imgURL = JTextEditor.class.getResource(path);
         if (imgURL != null) {
            return new ImageIcon(imgURL);
         } 
         else {
            System.err.println("Couldn't find file: " + path);
            return null;
         }
      }
   	
      public void createPopupMenu() 
      {
         JMenuItem menuItem;
      
        //Create the popup menu.
         JPopupMenu popup = new JPopupMenu();
         menuItem = new JMenuItem("A popup menu item");
         menuItem.addActionListener(this);
         popup.add(menuItem);
         menuItem = new JMenuItem("Another popup menu item");
         menuItem.addActionListener(this);
         popup.add(menuItem);
      
        //Add listener to the text area so the popup menu can come up.
         MouseListener popupListener = new PopupListener(popup);
         output.addMouseListener(popupListener);
      
      }
   
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
      private static void createAndShowGUI() 
      {
        //Create and set up the window.
         JFrame frame = new JFrame("JTextEditor");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      
        //Create and set up the content pane.
         JTextEditor jText = new JTextEditor();
         frame.setJMenuBar(jText.createMenuBar());
         frame.setContentPane(jText.createContentPane());
         jText.createPopupMenu();
      
        //Display the window.
         frame.setSize(450, 450);
         frame.setExtendedState(Frame.MAXIMIZED_BOTH);
         frame.setVisible(true);
      }
   
   	/**
   	 * Entry point into the application 
   	 * Starts the program in the event dispatch thread
   	 *
   	 * @param	args	The command line arguments
   	 */
      public static void main(String[] args) 
      {
         SwingUtilities.invokeLater(
               new Runnable() 
               {
                  public void run() 
                  {
                     createAndShowGUI();
                  }
               });
      }
   	
      private class PopupListener extends MouseAdapter 
      {
         JPopupMenu popup;
      
         PopupListener(JPopupMenu popupMenu) 
         {
            popup = popupMenu;
         }
      
         public void mousePressed(MouseEvent e) 
         {
            maybeShowPopup(e);
         }
      
         public void mouseReleased(MouseEvent e) 
         {
            maybeShowPopup(e);
         }
      
         private void maybeShowPopup(MouseEvent e) 
         {
            if (e.isPopupTrigger()) 
            {
               popup.show(e.getComponent(),
                           e.getX(), e.getY());
            }
         }
      }
   }

Then I use the readFileData() method to read this file into a JTextArea and the comments are organized the way I had them in the original file. This is what is in the JTextArea:

 import java.awt.*;
   import java.awt.event.*;
   import javax.swing.*;
	
   import java.io.*;
   import java.util.*;
	
   public class JTextEditor implements ActionListener
   {
      private JTextArea output;
      private JScrollPane scrollPane;
      private final String newline = "\n";
      private boolean saved  = false;
      private boolean opened = false;
      private boolean isNew  = false;
		private File currentFile;
		
   	
   	/**
   	 * Creates and configures the JMenuBar 
   	 * object for the JText editor
   	 *
   	 * @return The customized JMenuBar
   	 */
      public JMenuBar createMenuBar() 
      {
         JMenuBar menuBar;
         JMenu fileMenu, menu, submenu;
         JMenuItem newMenuItem, openMenuItem, saveMenuItem, exitMenuItem;
      
        //Create the menu bar.
         menuBar = new JMenuBar();
      
        //Build the File menu.
         fileMenu = new JMenu("File");
         fileMenu.setMnemonic(KeyEvent.VK_F);
         fileMenu.getAccessibleContext().setAccessibleDescription(
                "This is the File menu, users can create, open, " + 
            	 "and save documents, as well as exit the program");
         menuBar.add(fileMenu);
      
        //create the menu items for the fileMenu
         fileMenu.add(createMenuItem("New.." ,    "Lets users create a new document", true));
         fileMenu.add(createMenuItem("Open..",    "Lets users open a document"      , true));
         fileMenu.add(createMenuItem("Save..",    "Lets users save a document"      , true));
         fileMenu.add(createMenuItem("Save As..", "Lets users save a document"      , true));	
         fileMenu.add(createMenuItem("Exit..",    "Lets users exit the program"     , true));
      	      
         return menuBar;
      }
   	
   	/**
   	 * Creates a new JMenuItem object
   	 * 
   	 * @param name					The name of the JMenuItem
   	 * @param description		The description of the JMenuItem
   	 * @param actionListener	Whether or not this JMenuItem will need to register an
   	 *									ActionListener (yes, most of the time)
   	 * @return 						A new JMenuItem object
   	 */
      public JMenuItem createMenuItem(String name, String description, boolean actionListener)
      {
         JMenuItem menuItem = new JMenuItem(name);
         menuItem.getAccessibleContext().setAccessibleDescription(description);
      	
         if(actionListener)
            menuItem.addActionListener(this);
      		
         return menuItem;
      }
   	
      public void openFile()
      {
         File			 file;
         JFileChooser fc = new JFileChooser();
      	
         int returnVal = 0; 
      	
      	//prompt the user with the open file dialog
         returnVal = fc.showOpenDialog(output);
      	
         if(returnVal == JFileChooser.APPROVE_OPTION) //user selected and file and hit 'open'
         {
         	//store the file
            currentFile = file = fc.getSelectedFile();
            JOptionPane.showMessageDialog(null, "Opening " + file.getName() + ".");
            readFileData(file);
            opened = true;
         }
         else
         {
            JOptionPane.showMessageDialog(null, "Open command cancelled by user.");
      
      }
   	
   	//reads an input file and displays it in the text area
      public void readFileData(File file)
      {
         Scanner fileScanner = null;
            	
         try
         {
            fileScanner = new Scanner(file);
            while(fileScanner.hasNextLine())
            {
               String line = fileScanner.nextLine();
                     	
               //output is a JTextArea
               output.append(line + newline);
            }       	
         }
            catch(FileNotFoundException fnfe)
            {
               System.err.println(fnfe.getMessage());
            }
      }
   	
      public void writeFileData(File directory, File file)
      {
         BufferedWriter writer;
      	BufferedReader	reader;
			String line = "";
			
         try
         {
				reader = new BufferedReader(new InputStreamReader(new FileInputStream(currentFile)));
            writer = new BufferedWriter(new FileWriter(file));
				System.out.println(file);
				while((line = reader.readLine()) != null)
				{
					writer.write(line);
					writer.newLine();
				}
         	
         }       	
            catch(FileNotFoundException fnfe)
            {
               System.err.println(fnfe.getMessage());
            }
            catch(IOException ioe)
            {
               System.err.println(ioe.getMessage());
            }
      	
         JOptionPane.showMessageDialog(null, "Writing " + file.getName() + " to " + directory); 
      	
      }
   	
      public void saveFile()
      {
         File file;
         File directory;
         JFileChooser fc = new JFileChooser();
         int returnVal = 0;
      	
         if(opened)
         {
            returnVal = fc.showSaveDialog(output);
         	
            if(returnVal == JFileChooser.APPROVE_OPTION)
            {
            	//get the file the user selected to save
               file = fc.getSelectedFile();
               directory = fc.getCurrentDirectory();
               JOptionPane.showMessageDialog(null, "Saving " + file.getName() + ".");
               writeFileData(directory, file);
            }
            else
            {
               JOptionPane.showMessageDialog(null, "Save command cancelled by user.");
            }
         }
         else if(isNew)
         {
         	//saveFileAs();
         }
         else
         {
            JOptionPane.showMessageDialog(null, "You must create or open a document before saving.");
         }
      }
   
      public Container createContentPane() 
      {
        //Create the content-pane-to-be.
         JPanel contentPane = new JPanel(new BorderLayout());
         contentPane.setOpaque(true);
      
        //Create a scrolled text area.
         output = new JTextArea(5, 30);
         //output = new JTextPane();
         output.setFont(new Font("Monospaced", Font.PLAIN, 12));
         output.setEditable(false);
         scrollPane = new JScrollPane(output);
      
        //Add the text area to the content pane.
         contentPane.add(scrollPane, BorderLayout.CENTER);
      
         return contentPane;
      }
   	
      public void actionPerformed(ActionEvent ae) 
      {
         String command = ae.getActionCommand();
      
         String s = " command: " + command;
         JOptionPane.showMessageDialog(null, s);
         output.setCaretPosition(output.getDocument().getLength());
      	
         if(command.equals("New..")) //the New file option was selected
         {
            output.setEditable(true);
         	//createNewFile();
            isNew = true;
         }
         else if(command.equals("Open.."))//the Open file option was selected
         {
            output.setEditable(true);
            openFile();
         }
         else if(command.equals("Save.."))//the Save file option was selected
         {
            saveFile();
         }
         else if(command.equals("Save As.."))//the Save file option was selected
         {
         	//saveFileAs();
         }
         else if(command.equals("Exit.."))//the Exit program option was selected
         {
            String answer = "";
            if(opened && !saved)
            {
               answer = JOptionPane.showInputDialog(null, 
                  "You have not saved changes to this file, would you like to save your changes?");
            	
            	//if the user wants to save, call the save file method
               if(answer.equalsIgnoreCase("y") || answer.equalsIgnoreCase("yes"))
                  saveFile();
            }
            System.exit(0);
         }
      }   	
   	
   	// Returns just the class name -- no package info.
      protected String getClassName(Object o) 
      {
         String classString = o.getClass().getName();
         int dotIndex       = classString.lastIndexOf(".");
         return classString.substring(dotIndex+1);
      }
   
    /** Returns an ImageIcon, or null if the path was invalid. */
      protected static ImageIcon createImageIcon(String path) 
      {
         java.net.URL imgURL = JTextEditor.class.getResource(path);
         if (imgURL != null) {
            return new ImageIcon(imgURL);
         } 
         else {
            System.err.println("Couldn't find file: " + path);
            return null;
         }
      }
   	
      public void createPopupMenu() 
      {
         JMenuItem menuItem;
      
        //Create the popup menu.
         JPopupMenu popup = new JPopupMenu();
         menuItem = new JMenuItem("A popup menu item");
         menuItem.addActionListener(this);
         popup.add(menuItem);
         menuItem = new JMenuItem("Another popup menu item");
         menuItem.addActionListener(this);
         popup.add(menuItem);
      
        //Add listener to the text area so the popup menu can come up.
         MouseListener popupListener = new PopupListener(popup);
         output.addMouseListener(popupListener);
      
      }
   
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
      private static void createAndShowGUI() 
      {
        //Create and set up the window.
         JFrame frame = new JFrame("JTextEditor");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      
        //Create and set up the content pane.
         JTextEditor jText = new JTextEditor();
         frame.setJMenuBar(jText.createMenuBar());
         frame.setContentPane(jText.createContentPane());
         jText.createPopupMenu();
      
        //Display the window.
         frame.setSize(450, 450);
         frame.setExtendedState(Frame.MAXIMIZED_BOTH);
         frame.setVisible(true);
      }
   
   	/**
   	 * Entry point into the application 
   	 * Starts the program in the event dispatch thread
   	 *
   	 * @param	args	The command line arguments
   	 */
      public static void main(String[] args) 
      {
         SwingUtilities.invokeLater(
               new Runnable() 
               {
                  public void run() 
                  {
                     createAndShowGUI();
                  }
               });
      }
   	
      private class PopupListener extends MouseAdapter 
      {
         JPopupMenu popup;
      
         PopupListener(JPopupMenu popupMenu) 
         {
            popup = popupMenu;
         }
      
         public void mousePressed(MouseEvent e) 
         {
            maybeShowPopup(e);
         }
      
         public void mouseReleased(MouseEvent e) 
         {
            maybeShowPopup(e);
         }
      
         private void maybeShowPopup(MouseEvent e) 
         {
            if (e.isPopupTrigger()) 
            {
               popup.show(e.getComponent(),
                           e.getX(), e.getY());
            }
         }
      }
   }  
 }

As you can see the comments come out not lined up in the way they were in the original file. I am referring to the block comments at line 55+.

Hunter

[Paul Clapham]

Did you use tabs in those comments? If so, have you got the tab handling set up to work the same in the JTextPane and in wherever you created this text?

[Hunter McMillen]

I'm not sure if I used tabs or not, that seems like a likely reason. Also I didn't know that I could specify how tabs were read. Is that a JTextPane only setting? or will I be able to do that is JTextArea, which is what I am using.

Edit: I looked at the API closer and there is a setTabSize() method in the JTextArea class. I will look into that, thanks for the help everyone.

Hunter

[Rob Spoor]

Paul Clapham wrote:By the way I wouldn't have written any of that code. Here's the code I would have written:

output.read(new FileReader(file), null);

Surely you mean this:

Reader reader = new FileReader(file);
try
{
    output.read(reader, null);
}
finally
{
    reader.close();
}

After all, you should always close your resources.

[Campbell Ritchie]

Paul Clapham wrote:Did you use tabs . . .

Yes. some of the indentation is done with tabs and some with spaces.

You could have found that out, as I did, because you could use the "edit" button to inspect the code.

[Campbell Ritchie]

You can also copy the code from the "view plain" window onto a word-processor and use the "view non-printing characters" option.

[Hunter McMillen]

Rob Spoor wrote:

Paul Clapham wrote:By the way I wouldn't have written any of that code. Here's the code I would have written:

output.read(new FileReader(file), null);

Surely you mean this:

Reader reader = new FileReader(file);
try
{
    output.read(reader, null);
}
finally
{
    reader.close();
}

After all, you should always close your resources.

I had seen the read() method in the JTextComponent method list, but didn't use it immediately. The overall goal of this is for me to be able to create a text editor for .java and other files. Swing is also an area of Java where I am very weak, which is another reason I am doing this project. Thank you all for your advice. I am sure that I will have more questions as I make progress in this project.

Hunter