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1 | package be.nikiroo.utils.ui; |
2 | ||
3 | import java.awt.event.ActionEvent; | |
4 | import java.awt.event.ActionListener; | |
5 | import java.util.LinkedList; | |
6 | import java.util.Queue; | |
7 | ||
8 | import javax.swing.JPanel; | |
9 | ||
10 | /** | |
11 | * A {@link JPanel} with the default {@link ActionListener} add/remove/fire | |
12 | * methods. | |
13 | * <p> | |
14 | * Note that it will queue all events until at least one listener comes (or | |
15 | * comes back!); this first (or at least currently unique) listener will drain | |
16 | * the queue. | |
17 | * | |
18 | * @author niki | |
19 | */ | |
4d4527e7 | 20 | public class ListenerPanel extends JPanel implements ListenerItem { |
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21 | private static final long serialVersionUID = 1L; |
22 | ||
23 | /** Waiting queue until at least one listener is here to get the events. */ | |
24 | private final Queue<ActionEvent> waitingQueue; | |
25 | ||
26 | /** | |
27 | * Create a new {@link ListenerPanel}. | |
28 | */ | |
29 | public ListenerPanel() { | |
30 | waitingQueue = new LinkedList<ActionEvent>(); | |
31 | } | |
32 | ||
4d4527e7 | 33 | @Override |
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34 | public synchronized boolean hasListeners() { |
35 | return listenerList.getListenerList().length > 1; | |
36 | } | |
37 | ||
4d4527e7 | 38 | @Override |
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39 | public synchronized int getWaitingEventCount() { |
40 | return waitingQueue.size(); | |
41 | } | |
42 | ||
4d4527e7 | 43 | @Override |
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44 | public synchronized void addActionListener(ActionListener listener) { |
45 | if (!hasListeners()) { | |
46 | while (!waitingQueue.isEmpty()) { | |
47 | listener.actionPerformed(waitingQueue.remove()); | |
48 | } | |
49 | } | |
50 | ||
51 | listenerList.add(ActionListener.class, listener); | |
52 | } | |
53 | ||
4d4527e7 | 54 | @Override |
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55 | public synchronized void removeActionListener(ActionListener listener) { |
56 | listenerList.remove(ActionListener.class, listener); | |
57 | } | |
58 | ||
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59 | @Override |
60 | public synchronized void fireActionPerformed(String listenerCommand) { | |
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61 | ActionEvent e = new ActionEvent(this, ActionEvent.ACTION_PERFORMED, |
62 | listenerCommand); | |
63 | ||
64 | ActionListener[] listeners = getListeners(ActionListener.class); | |
65 | if (listeners.length > 0) { | |
66 | for (ActionListener action : listeners) { | |
67 | action.actionPerformed(e); | |
68 | } | |
69 | } else { | |
70 | waitingQueue.add(e); | |
71 | } | |
72 | } | |
73 | } |