java coloured scroll bar search result

Question

How would I go about customizing a scroll bar in Java so that I could have a search that acts like chrome, that's to say puts coloured stripes where the results are?

I don't want a library as I'd prefer to code it myself. Plus I don't want to loose my L&F that I have. Examples welcome.

Actually it will be to view a large text file or a long jtable, and does anyone have any good ideas for how I could have an efficient scroll bar to view this? ... should I have a double scroll bar one beginning to end and an inner one which scrolls over a short range???

(sorry it's kind of a double question but it's the coloured scroll bar that will get the tick)

Thanks for all your possible help and ideas.

EDIT: No code example sorry as I'm trying to plan this out in my head before hand... You see it will be a long text pane with a quick search. Users will need to load in this large file and get quick access to details. For the moment I'm keeping it light for loading speeds. Secondly the text will be dynamic so by clicking on a word it will put a stripe in the scroll bar as if the search was activated. For the moment lets just say it is a simple text area with scroll bar.

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.regex.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.plaf.metal.MetalScrollBarUI;

public class ScrollBarSearchHighlighterTest {
  private static final Highlighter.HighlightPainter highlightPainter
    = new DefaultHighlighter.DefaultHighlightPainter(Color.YELLOW);
  private static final String pattern = "Swing";
  private static final String initTxt =
    "Trail: Creating a GUI with JFC/Swing\n" +
    "Lesson: Learning Swing by Example\n" +
    "This lesson explains the concepts you need to\n" +
    " use Swing components in building a user interface.\n" +
    " First we examine the simplest Swing application you can write.\n" +
    " Then we present several progressively complicated examples of creating\n" +
    " user interfaces using components in the javax.swing package.\n" +
    " We cover several Swing components, such as buttons, labels, and text areas.\n" +
    " The handling of events is also discussed,\n" +
    " as are layout management and accessibility.\n" +
    " This lesson ends with a set of questions and exercises\n" +
    " so you can test yourself on what you've learned.\n" +
    "http://docs.oracle.com/javase/tutorial/uiswing/learn/index.html\n";

  private final JTextArea textArea   = new JTextArea();
  private final JScrollPane scroll   = new JScrollPane(textArea);
  private final JScrollBar scrollbar = new JScrollBar(JScrollBar.VERTICAL);
  public JComponent makeUI() {
    textArea.setEditable(false);
    textArea.setLineWrap(true);
    textArea.setText(initTxt+initTxt+initTxt);
    scrollbar.setUnitIncrement(10);

    scrollbar.setUI(new MetalScrollBarUI() {
      @Override protected void paintTrack(
            Graphics g, JComponent c, Rectangle trackBounds) {
        super.paintTrack(g, c, trackBounds);
        Rectangle rect = textArea.getBounds();
        double sy = trackBounds.getHeight() / rect.getHeight();
        AffineTransform at = AffineTransform.getScaleInstance(1.0, sy);
        Highlighter highlighter = textArea.getHighlighter();
        g.setColor(Color.YELLOW);
        try{
          for(Highlighter.Highlight hh: highlighter.getHighlights()) {
            Rectangle r = textArea.modelToView(hh.getStartOffset());
            Rectangle s = at.createTransformedShape(r).getBounds();
            int h = 2; //Math.max(2, s.height-2);
            g.fillRect(trackBounds.x+2, trackBounds.y+1+s.y, trackBounds.width, h);
          }
        } catch(BadLocationException e) {
          e.printStackTrace();
        }
      }
    });
    scroll.setVerticalScrollBar(scrollbar);

    Box box = Box.createHorizontalBox();
    box.add(Box.createHorizontalGlue());
    box.add(new JButton(new AbstractAction("highlight") {
      @Override public void actionPerformed(ActionEvent e) {
        setHighlight(textArea, pattern);
      }
    }));
    box.add(Box.createHorizontalStrut(2));
    box.add(new JButton(new AbstractAction("clear") {
      @Override public void actionPerformed(ActionEvent e) {
        textArea.getHighlighter().removeAllHighlights();
        scrollbar.repaint();
      }
    }));

    JPanel p = new JPanel(new BorderLayout());
    p.add(scroll);
    p.add(box, BorderLayout.SOUTH);
    return p;
  }
  public void setHighlight(JTextComponent jtc, String pattern) {
    Highlighter highlighter = jtc.getHighlighter();
    highlighter.removeAllHighlights();
    Document doc = jtc.getDocument();
    try{
      String text = doc.getText(0, doc.getLength());
      Matcher matcher = Pattern.compile(pattern).matcher(text);
      int pos = 0;
      while(matcher.find(pos)) {
        int start = matcher.start();
        int end   = matcher.end();
        highlighter.addHighlight(start, end, highlightPainter);
        pos = end;
      }
    }catch(BadLocationException e) {
      e.printStackTrace();
    }
    scroll.repaint();
  }
  public void removeHighlights(JTextComponent jtc) {
    Highlighter hilite = jtc.getHighlighter();
    Highlighter.Highlight[] hilites = hilite.getHighlights();
    for(int i=0; i<hilites.length; i++) {
      if(hilites[i].getPainter() instanceof
             DefaultHighlighter.DefaultHighlightPainter) {
        hilite.removeHighlight(hilites[i]);
      }
    }
    scroll.repaint();
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    frame.getContentPane().add(new ScrollBarSearchHighlighterTest().makeUI());
    frame.setSize(320, 240);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

Or another option is to use "MatteBorder + Icon + RowHeader": JScrollBar search highlighter