package be.nikiroo.utils.ui;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import java.util.Queue;
import javax.swing.JPanel;
/**
* A {@link JPanel} with the default {@link ActionListener} add/remove/fire
* methods.
*
* Note that it will queue all events until at least one listener comes (or
* comes back!); this first (or at least currently unique) listener will drain
* the queue.
*
* @author niki
*/
public class ListenerPanel extends JPanel implements ListenerItem {
private static final long serialVersionUID = 1L;
/** Waiting queue until at least one listener is here to get the events. */
private final Queue waitingQueue;
/**
* Create a new {@link ListenerPanel}.
*/
public ListenerPanel() {
waitingQueue = new LinkedList();
}
@Override
public synchronized boolean hasListeners() {
return listenerList.getListenerList().length > 1;
}
@Override
public synchronized int getWaitingEventCount() {
return waitingQueue.size();
}
@Override
public synchronized void addActionListener(ActionListener listener) {
if (!hasListeners()) {
while (!waitingQueue.isEmpty()) {
listener.actionPerformed(waitingQueue.remove());
}
}
listenerList.add(ActionListener.class, listener);
}
@Override
public synchronized void removeActionListener(ActionListener listener) {
listenerList.remove(ActionListener.class, listener);
}
@Override
public synchronized void fireActionPerformed(String listenerCommand) {
ActionEvent e = new ActionEvent(this, ActionEvent.ACTION_PERFORMED,
listenerCommand);
ActionListener[] listeners = getListeners(ActionListener.class);
if (listeners.length > 0) {
for (ActionListener action : listeners) {
action.actionPerformed(e);
}
} else {
waitingQueue.add(e);
}
}
}