You'd better use JTextPane or JEditorPane, instead of JTextArea.
A text area is a "plain" text component, which means taht although it can display text in any font, all of the text is in the same font.
So, JTextArea is not a convenient component to make any text formatting.
On the contrary, using JTextPane or JEditorPane, it's quite easy to change style (highlight) of any part of loaded text.
See How to Use Editor Panes and Text Panes for details.
Update:
The following code highlights the desired part of your text.
It's not exectly what you want. It simply finds the exact phrase in the text.
But I hope that if you apply your algorithms, you can easily
modify it to fit your needs.
import java.lang.reflect.InvocationTargetException;
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
public class LineHighlightPainter {
String revisedText = "Extreme programming is one approach "
+ "of agile software development which emphasizes on frequent"
+ " releases in short development cycles which are called "
+ "time boxes. This result in reducing the costs spend for "
+ "changes, by having multiple short development cycles, "
+ "rather than one long one. Extreme programming includes "
+ "pair-wise programming (for code review, unit testing). "
+ "Also it avoids implementing features which are not included "
+ "in the current time box, so the schedule creep can be minimized. ";
String token = "Extreme programming includes pair-wise programming";
public static void main(String args[]) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
new LineHighlightPainter().createAndShowGUI();
}
});
} catch (InterruptedException ex) {
// ignore
} catch (InvocationTargetException ex) {
// ignore
}
}
public void createAndShowGUI() {
JFrame frame = new JFrame("LineHighlightPainter demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextArea area = new JTextArea(9, 45);
area.setLineWrap(true);
area.setWrapStyleWord(true);
area.setText(revisedText);
// Highlighting part of the text in the instance of JTextArea
// based on token.
highlight(area, token);
frame.getContentPane().add(new JScrollPane(area), BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
// Creates highlights around all occurrences of pattern in textComp
public 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 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]);
}
}
}
// An instance of the private subclass of the default highlight painter
Highlighter.HighlightPainter myHighlightPainter = new MyHighlightPainter(Color.red);
// A private subclass of the default highlight painter
class MyHighlightPainter
extends DefaultHighlighter.DefaultHighlightPainter {
public MyHighlightPainter(Color color) {
super(color);
}
}
}
This example is based on Highlighting Words in a JTextComponent.
