Mega Code Archive
Single instance status bar
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/*
* Copyright 2002 Sun Microsystems, Inc. All rights reserved.
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* without modification, are permitted provided that the following
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*
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*
* - Redistribution in binary form must reproduce the above
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* provided with the distribution.
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* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any
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* DAMAGES OR LIABILITIES SUFFERED BY LICENSEE AS A RESULT OF OR
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*
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*/
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.*;
/**
* Single instance status bar.
* <p>
* This class is also a MouseListener which listens to MOUSE_ENTERED
* and MOUSE_EXITED events from Action derived components so that
* the value of the Action.LONG_DESCRIPTION key is sent as a message
* to the status bar.
* <p>
* To enable this behavior, add the StatusBar
* instance as a MouseListener to the component that was created from
* an Action.
*
* @version 1.6 01/15/03
* @author Mark Davidson
*/
public class StatusBar extends JPanel implements MouseListener {
private JLabel label;
private Dimension preferredSize;
private static StatusBar INSTANCE;
public StatusBar() {
this.setLayout(new FlowLayout(FlowLayout.LEFT));
this.setBorder(BorderFactory.createEtchedBorder());
// Set a large blank label to set the preferred size.
label = new JLabel(" ");
preferredSize = new Dimension(getWidth(label.getText()), 2 * getFontHeight());
this.add(label);
}
/**
* Return the instance of the StatusBar. If this has not been explicity
* set then it will be created.
*
* @return the StatusBar instance.
* @see #setInstance
*/
public static StatusBar getInstance() {
if (INSTANCE == null) {
INSTANCE = new StatusBar();
}
return INSTANCE;
}
/**
* Sets the StatusBar instance.
*/
public static void setInstance(StatusBar status) {
INSTANCE = status;
}
/**
* Returns the string width
* @param s the string
* @return the string width
*/
protected int getWidth(String s) {
FontMetrics fm = this.getFontMetrics(this.getFont());
if (fm == null) {
return 0;
}
return fm.stringWidth(s);
}
/**
* Returns the height of a line of text
* @return the height of a line of text
*/
protected int getFontHeight() {
FontMetrics fm = this.getFontMetrics(this.getFont());
if (fm == null) {
return 0;
}
return fm.getHeight();
}
/**
* Returns the perferred size
* @return the preferred size
*/
public Dimension getPreferredSize() {
return preferredSize;
}
/**
* Sets non-transient status bar message
* @param message the message to display on the status bar
*/
public void setMessage(String message) {
label.setText(message);
}
//
// MouseListener methods
//
public void mouseClicked(MouseEvent evt) {}
public void mousePressed(MouseEvent evt) {}
public void mouseReleased(MouseEvent evt) {}
public void mouseExited(MouseEvent evt) {
setMessage("");
}
/**
* Takes the LONG_DESCRIPTION of the Action based components
* and sends them to the Status bar
*/
public void mouseEntered(MouseEvent evt) {
if (evt.getSource() instanceof AbstractButton) {
AbstractButton button = (AbstractButton)evt.getSource();
Action action = button.getAction();
if (action != null) {
String message = (String)action.getValue(Action.LONG_DESCRIPTION);
setMessage(message);
}
}
}
/**
* Helper method to recursively register all MenuElements with
* a mouse listener.
*/
public void registerMouseListener(MenuElement[] elements) {
for (int i = 0; i < elements.length; i++) {
if (elements[i] instanceof JMenuItem) {
((JMenuItem)elements[i]).addMouseListener(this);
}
registerMouseListener(elements[i].getSubElements());
}
}
/**
* Helper method to register all components with a mouse listener.
*/
public void registerMouseListener(Component[] components) {
for (int i = 0; i < components.length; i++) {
if (components[i] instanceof AbstractButton) {
((AbstractButton)components[i]).addMouseListener(this);
}
}
}
} // end class StatusBar
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