JTextPane Colour Highlighting

Question

Im doing up a prototype of a compiler, i have certain keywords like "if"s and "elses" etc etc which i would like to be colour coded differently!!! My problem is when i have big files the time it takes to colour code and display is horrendous!!! I just want to know am i going about the right way in highlighting my keywords?? is there a better way or how can i improve my current code!!! any suggestions at all are welcome!! heres a sample of code..
public class MyDoc extends DefaultStyledDocument
static MutableAttributeSet setAttr, ifAttr, defaultAttr;
public MyDoc()
setAttr = new SimpleAttributeSet();
StyleConstants.setForeground(setAttr, Color.red);
ifAttr = new SimpleAttributeSet();
StyleConstants.setForeground(ifAttr, Color.blue);
defaultAttr = new SimpleAttributeSet();
StyleConstants.setForeground(defaultAttr, Color.black);
public void insertString(int offs, String str, AttributeSet a) throws
BadLocationException
if (str == null) return;
StringTokenizer tokenizer = new StringTokenizer(str," \n",true);
try
while( tokenizer.hasMoreTokens())
String token = (String)tokenizer.nextElement();
if(token.length() == 0)
continue;
if (token.compareTo("set") == 0)
super.insertString(offs, token, setAttr);
} else if (token.compareTo("if") == 0)
super.insertString(offs, token, ifAttr);
} else
super.insertString(offs,token, defaultAttr);
offs = offs + token.length();
} catch (BadLocationException ble)
System.err.println("MyDoc::insertString()"+ble.toString());
}catch(Exception e)
System.err.println("MyDoc::insertString()"+e.toString());
bottom line is that im looking for some other way, more elegant way of getting keywords highlighted, the above is nasty!!!
cheers people,
JB.

Answer 1

I have tried a couple of different approaches for using threads:
1) Load the data into the text pane and then use a thread for highlighting. The highlighting got messed up if you type data in the text pane while the highlighting thread is working. This approach won't work with the current structure of the SyntaxDocument.
2) Load data into the text pane in smaller pieces. This approach shows a little more promise as the text pane is shown with initial data in a couple of seconds. However, the entire load time goes from 15 to 26 seconds. During this 26 second load time you can type data and scroll, but the text pane reacts very slowly. I haven't verified that data inserted into the document by typing does not cause problems with data being loaded into the document by the background thread. (Swing components are not thread safe, but hopefully insertion of data into the document is). Here is the test class:
import java.awt.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;
public class LoadTextPane extends JFrame
     char[] data;
     JTextPane textPane;
     public LoadTextPane(String fileName)
          EditorKit editorKit = new StyledEditorKit()
               public Document createDefaultDocument()
                    return new SyntaxDocument();
          textPane = new JTextPane();
         textPane.setEditorKitForContentType("text/java", editorKit);
         textPane.setContentType("text/java");
          JScrollPane sp = new JScrollPane(textPane);
          getContentPane().add( sp );
          long startTime = new Date().getTime();
          try
               File f = new File( fileName );
               FileReader in = new FileReader( f );
               int size = (int) f.length();
               data = new char[ size ];
               int chars_read = 0;
               while( chars_read < size )
                    chars_read += in.read( data, chars_read, size - chars_read );
               in.close();
               long endTime=new Date().getTime();
               System.out.println( "File size: " + chars_read );
               // System.out.println( data );
          catch (IOException sse)
               System.out.println("Error has occured"+sse);
          System.out.println( "Time to read file: " + (new Date().getTime() - startTime ));
          if (data.length > 8092)
               Thread load = new LoadThread(data, textPane.getDocument());
               load.start();
          else
               textPane.setText( new String(data, 0, data.length) );
     public static void main( String[] args )
          String fileName = "c:/java/jdk1.3/src/java/awt/Component.java";
          JFrame f = new LoadTextPane(fileName);
          f.setDefaultCloseOperation( EXIT_ON_CLOSE );
          f.setSize( 1000, 600);
          f.setVisible(true);
     class LoadThread extends Thread
          char[] data;
          Document doc;
          LoadThread(char[] data, Document doc)
               this.data = data;
               this.doc = doc;
          public void run()
              int start = 0;
              int end = data.length;
              int increment = 8192;
               long begin = System.currentTimeMillis();
              while ( start < end )
                   if (start + increment > end)
                        increment = end - start;
                   String text = new String(data, start, increment);
                   try
                        doc.insertString(doc.getLength(), text, null);
                   catch(BadLocationException e)
                        System.out.println(e);
                   start += increment;
                    //  allow some time for the gui to process typed text, scrolling etc
//                    try { Thread.sleep(300); }
//                    catch (Exception e) {}
               System.out.println( "Load Text Pane: " + (System.currentTimeMillis() - begin) );
}