Java Console Apps Made Easy

package javaConsole;

import java.awt.Graphics;
import java.awt.Rectangle;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultCaret;
import javax.swing.text.JTextComponent;

/**
 * @brief Custom block caret for the Java Console.
 * 
 * @par Comments:
 * 		 Adapted from http://www.java2s.com/Code/Java/Swing-JFC/Acustomcaretclass.htm
 * 
 * @author David MacDermot
 *
 * @date 02-07-2012
 * 
 * @bug
 */
public class BlockCaret extends DefaultCaret {

	private static final long serialVersionUID = 1L;

	/**
	 * @brief Class Constructor
	 */
	public BlockCaret() {
		setBlinkRate(500); // half a second
	}

	/* (non-Javadoc)
	 * @see javax.swing.text.DefaultCaret#damage(java.awt.Rectangle)
	 */
	protected synchronized void damage(Rectangle r) {
		if (r == null)
			return;

		// give values to x,y,width,height (inherited from java.awt.Rectangle)
		x = r.x;
		y = r.y;
		height = r.height;
		// A value for width was probably set by paint(), which we leave alone.
		// But the first call to damage() precedes the first call to paint(), so
		// in this case we must be prepared to set a valid width, or else
		// paint()
		// will receive a bogus clip area and caret will not get drawn properly.
		if (width <= 0)
			width = getComponent().getWidth();
		
		repaint();  //Calls getComponent().repaint(x, y, width, height) to erase 
		repaint();	// previous location of caret.  Sometimes one call isn't enough.
	}

	/* (non-Javadoc)
	 * @see javax.swing.text.DefaultCaret#paint(java.awt.Graphics)
	 */
	public void paint(Graphics g) {
		JTextComponent comp = getComponent();

		if (comp == null)
			return;

		int dot = getDot();
		Rectangle r = null;
		char dotChar;
		try {
			r = comp.modelToView(dot);
			if (r == null)
				return;
			dotChar = comp.getText(dot, 1).charAt(0);
		} catch (BadLocationException e) {
			return;
		}

		if(Character.isWhitespace(dotChar)) dotChar = '_';

		if ((x != r.x) || (y != r.y)) {
			// paint() has been called directly, without a previous call to
			// damage(), so do some cleanup. (This happens, for example, when
			// the text component is resized.)
			damage(r);
			return;
		}

		g.setColor(comp.getCaretColor());
		g.setXORMode(comp.getBackground()); // do this to draw in XOR mode

		width = g.getFontMetrics().charWidth(dotChar);
		if (isVisible())
			g.fillRect(r.x, r.y, width, r.height);
	}
}