GhostText.java

//from http://stackoverflow.com/questions/10506789/how-to-display-faint-gray-ghost-text-in-a-jtextfield
//If you're the owner and you don't want it here, don't DMCA. Talk to me for licensing instead.

package disparity.game.editor;

import java.awt.Color;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class GhostText implements FocusListener, DocumentListener,
PropertyChangeListener {

	private final JTextField textfield;
	private boolean isEmpty;
	private Color ghostColor;
	private Color foregroundColor;
	public final String ghostText;

	protected GhostText(final JTextField textfield, String ghostText) {
		super();
		this.textfield = textfield;
		this.ghostText = ghostText;
		this.ghostColor = Color.LIGHT_GRAY;
		textfield.addFocusListener(this);
		registerListeners();
		updateState();
		if (!this.textfield.hasFocus()) {
			focusLost(null);
		}
	}

	public void delete() {
		unregisterListeners();
		textfield.removeFocusListener(this);
	}

	private void registerListeners() {
		textfield.getDocument().addDocumentListener(this);
		textfield.addPropertyChangeListener("foreground", this);
	}

	private void unregisterListeners() {
		textfield.getDocument().removeDocumentListener(this);
		textfield.removePropertyChangeListener("foreground", this);
	}

	public Color getGhostColor() {
		return ghostColor;
	}

	public void setGhostColor(Color ghostColor) {
		this.ghostColor = ghostColor;
	}

	private void updateState() {
		isEmpty = textfield.getText().length() == 0;
		foregroundColor = textfield.getForeground();
	}

	@Override
	public void propertyChange(PropertyChangeEvent evt) {
		updateState();
	}

	@Override
	public void changedUpdate(DocumentEvent e) {
		updateState();
	}

	@Override
	public void insertUpdate(DocumentEvent e) {
		updateState();
	}

	@Override
	public void removeUpdate(DocumentEvent e) {
		updateState();
	}

	@Override
	public void focusLost(FocusEvent e) {
		if (isEmpty) {
			unregisterListeners();
			try {
				textfield.setText(ghostText);
				textfield.setForeground(ghostColor);
			} finally {
				registerListeners();
			}
		}
	}

	@Override
    public void focusGained(FocusEvent e) {
        if (isEmpty) {
            unregisterListeners();
            try {
                textfield.setText("");
                textfield.setForeground(foregroundColor);
            } finally {
                registerListeners();
            }
        }

    }

}