Highlighting few of the words of a text file opened in a frame

Question

I am opening a file in a frame and I wish to highlight few of the words.As I understand,I need to traverse the content of the file. How do I traverse through the contents an

Answer 1

To highlight on a JEditorPane have a look at this example:

import java.awt.Color;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Document;
import javax.swing.text.Highlighter;
import javax.swing.text.JTextComponent;

public class Test {

    // An instance of the subclass of the default highlight painter
    static MyHighlightPainter myHighlightPainter = new MyHighlightPainter(Color.red);

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                JEditorPane jep = new JEditorPane();
                jep.setText("Hello to the public");
                frame.add(jep);
                frame.pack();
                frame.setVisible(true);

                highlight(jep, "public");//'public is the word to highligh'

            }
        });
    }

    // Creates highlights around all occurrences of pattern in textComp
    public static void highlight(JTextComponent textComp, String pattern) {
        // First remove all old highlights
        removeHighlights(textComp);

        try {
            Highlighter hilite = textComp.getHighlighter();
            Document doc = textComp.getDocument();
            String text = doc.getText(0, doc.getLength());
            int pos = 0;

            // Search for pattern
            while ((pos = text.indexOf(pattern, pos)) >= 0) {
                // Create highlighter using private painter and apply around pattern
                hilite.addHighlight(pos, pos + pattern.length(), myHighlightPainter);
                pos += pattern.length();
            }
        } catch (BadLocationException e) {
        }
    }

    // Removes only our private highlights
    public static void removeHighlights(JTextComponent textComp) {
        Highlighter hilite = textComp.getHighlighter();
        Highlighter.Highlight[] hilites = hilite.getHighlights();

        for (int i = 0; i < hilites.length; i++) {
            if (hilites[i].getPainter() instanceof MyHighlightPainter) {
                hilite.removeHighlight(hilites[i]);
            }
        }
    }
}

class MyHighlightPainter extends DefaultHighlighter.DefaultHighlightPainter {

    public MyHighlightPainter(Color color) {
        super(color);
    }
}