Too much data for JTextArea

Question

Howdy people, I've been stuck on this problem for a while now. I writing a povvy hex-editor, and it works (yay!), but when I open largish files (>= 20kB) it really chokes on it. Not on the conversion from bytes to hex string, but (you guessed it) displaying it in the JTextArea. I've tried a couple of things. Make it a Thread (so it can update a pretty progress bar), I tried appending the data in sections, instead of one giant setText().... No go.
Here's what I have so far:
import javax.swing.JTextArea;
public class DisplayThread extends Thread
    private static final int BUFSIZE = 100000;
    private FileEditor parent;
    private JTextArea textArea;
    private StringBuffer data;
    private ProgressDialog pd;
    public DisplayThread(FileEditor p, JTextArea jta, StringBuffer s, ProgressDialog pr)
        parent = p;
        textArea = jta;
        data = s;
        pd = pr;
    public void run()
        System.out.println("starting DisplayThread");
        long time = System.currentTimeMillis();
        textArea.setText("");
        int len = data.length();
        for(int i=0;i<len;i+=BUFSIZE)
            int n = (i+BUFSIZE<len)?i+BUFSIZE:len;
            textArea.append(data.substring(i,n));
            pd.setProgress(i, len);
        System.out.println("It took " + (System.currentTimeMillis() - time) + "ms by buffering");
        time = System.currentTimeMillis();
        textArea.setText(data.toString());
        System.out.println("It took " + (System.currentTimeMillis() - time) + "ms directly");
        textArea.setEditable(true);
        pd.setVisible(false);
        System.out.println("finishing DisplayThread");
}At the moment I've got both the "bit-by-bit" display method, and the "one-shot-setText()" methods going to compare times, but check out these times for a 900k file...
It took 673439ms by buffering
It took 137628ms directly
For the first one, that's over 11 mins!!!!
Anyway, I did searches on what to do in this scenario, one answer was Don't!, the other was "only display what's necessary".
So...
I've tried to create a "BufferedJTextArea", and only set the text according to what will be visible in the scrollpane/scrollbar, but it's not working (all sorts of complications with adding a scrollbar to a JTextArea, or adding a JTextArea to a scrollPane....)
Also, even after it loads all the data into the JTextArea, it takes it's sweet time to repaint...
Any ideas on how to make it faster? Continue with the "BufferedJTextArea" (if that's the case, that'll be the next question)?
Or give up and warn ppl not to load files larger than about 15k?
Thanks ppl,
Radish21

Answer 1

But with a JList, you can only have one column, right? That'd mean I have to break up the String with \n all over the place.
I did look at JTable first, and even tried to use one, but I've never used them before, and now I know why. Too damn difficult.
I'm getting closer now, but still having hiccups (or is it hiccoughs? :)
I had to make the class a JPanel itself, that adds a BufferedTextArea to a JScrollPane... it works, so why fix it? ;)
import javax.swing.JTextArea;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JPanel;
import java.awt.event.AdjustmentListener;
import java.awt.event.AdjustmentEvent;
public class BufferedJTextArea extends JPanel
    protected BJTextArea textArea;
    protected JScrollPane scrollPane;
    public BufferedJTextArea()
        textArea = new BJTextArea();
        scrollPane = new JScrollPane(textArea);
        scrollPane.getVerticalScrollBar().addAdjustmentListener(textArea);
        setVisible(true);
        setLayout(new java.awt.BorderLayout());
        add(scrollPane, "Center");
    public void setText(String s)
        textArea.setText(s);
    private class BJTextArea extends JTextArea implements AdjustmentListener
        protected static final int BUF_SIZE = 4096; // display 4kB at a time
        protected String data;
        protected int len, startIndex = 0, endIndex = 0;
        private java.awt.FontMetrics fontMetrics;
        private int val = 0;
        public BJTextArea()
            super();
            setLineWrap(true);
            setVisible(true);
            fontMetrics = getFontMetrics(getFont());
        public void adjustmentValueChanged(AdjustmentEvent e)
            val = e.getValue();
            adjustView();
        public void setText(String s)
            data = s;
            len = data.length();
            startIndex = 0;
            if(len <= BUF_SIZE)
                endIndex = len;
                super.setText(data);
            else
                endIndex = -1;
                val = 0;
                adjustView();
        protected void adjustView()
            if(endIndex == -1 && startIndex == 0)
                endIndex = java.lang.Math.min(len, BUF_SIZE);
                super.setText(data.substring(startIndex, endIndex));
                return;
            if(len <= BUF_SIZE)
                return;
            int startLine = scrollPane.getVerticalScrollBar().getValue() / getRowHeight();
            int linesVisible = // haven't worked out what goes here yet
            // Some way to work out whether I need to adjust things.
}Anyway, thanks for the tips, but I think you're right, I'll stick with the BufferedJTextArea....
If you have any ideas about checking for if the view is about to get out of range, let me know. Also, I've tried setting the vertical scrollbar's maximum value, but it ignores me (because I need it to be reflect the entire data string, not just the segment displayed). If you have any ideas, they'd be greatly appreciated.
Cheers,
Radish21