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  1. #1
    jkhoa is offline Member
    Join Date
    Aug 2007
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    Default How come multi thread don't look like it?

    Hi I'm still realtively new to java and really new to threads, so please bear with me.

    I'm basically making a an applet that has a jtextpane, and when you type stuff in it changes the color of the numbers from the standard black to red. Im trying to make however a seperate thread that searches and colors the jtextpane. It seems to work right now but it is extremely slow, I just wondering if this setup is really making the system run multi threads.

    public class TEV3 extends JApplet implements ActionListener{
    public void init() {
    final sh_Brackets setsThread = new sh_Brackets();
    TA.getDocument().addDocumentListener(new DocumentListener(){

    // This method is called after an insert into the document
    public void insertUpdate(DocumentEvent evt) {
    setsThread.displayText = rawString;

    and then the other class basically is this

    public class sh_Brackets extends Thread{
    public void run(){
    //displayText do whatever here to color

    thanks in advance for any help

  2. #2
    hardwired's Avatar
    hardwired is offline Senior Member
    Join Date
    Jul 2007
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    Default DocumentFilter

    With a continuously–running loop that is busy styling all of the text in the textPane, called by a DocumentListener, I would say that your app could run very slow.
    A lighter–weight way to do this is with a simple DocumentFilter. Here's one way you could put it together:
    Java Code:
    //  <applet code="TEV3Rx" width="400" height="400"></applet>
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
    import javax.swing.text.*;
    public class TEV3Rx extends JApplet {
        public void init() {
            JTextPane textPane = new JTextPane();
            Style style = textPane.addStyle("basic", null);
            StyleConstants.setFontSize(style, 18);
            StyleConstants.setFontFamily(style, "Lucida Sans Unicode");
            style = textPane.addStyle("redDigits", null);
            AbstractDocument doc = (AbstractDocument)textPane.getDocument();
            doc.setDocumentFilter(new DigitFilter(style));
        public static void main(String[] args) {
            JApplet applet = new TEV3Rx();
            JFrame f = new JFrame();
    class DigitFilter extends DocumentFilter {
        String domain = "0123456789";
        Style digitStyle;
        public DigitFilter(Style style) {
            digitStyle = style;
        public void insertString(DocumentFilter.FilterBypass fb,
                                 int offset,
                                 String str,
                                 AttributeSet attrs) throws BadLocationException {
            replace(fb, offset, 0, str, attrs);
        public void replace(DocumentFilter.FilterBypass fb,
                            int offset,
                            int length,               // selected text
                            String str,               // incoming string
                            AttributeSet attrs) throws BadLocationException {
            char[] source = str.toCharArray();
            char[] result = new char[source.length + 2];
            int k = 0;
            for(int j = 0; j < source.length; j++) {
                result[k++] = source[j];
                fb.replace(offset, length, new String(result, 0, k), attrs);
                if(domain.indexOf(source[j]) != -1) {
                    StyledDocument doc = (StyledDocument)fb.getDocument();
                    doc.setCharacterAttributes(offset, 1, digitStyle, false);

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