/**
* \cond LICENSE
* ********************************************************************
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*
* JCarrierPigeon - A notification library
* Copyright (c) 2010, Paulo Roberto Massa Cereda
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
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*
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* \endcond
*
* <b>NotificationQueue.java</b>: handles the display of notifications.
* This class was created to act as a notification manager instead of
* allowing multiple windows at once. Use this class together with
* the new <b>net.sf.jcarrierpigeon.Notification</b> class.
*/
package net.sf.jcarrierpigeon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import java.util.Queue;
import javax.swing.Timer;
/**
* Handles the display of notifications. This class was created to act as a
* notification manager instead of allowing multiple windows at once. I just
* realized that too many notifications being displayed at once won't be
* fully noticed by the user, so a queue system for notifications was a wiser
* choice. From version 1.3 of JCarrierPigeon, multiple window support is
* replaced by a notification queue system, where only a single notification is
* shown per time.
*
* Please note that this notification manager handles the calls for methods
* of the <b>net.sf.jcarrierpigeon.Notification</b> class. After adding a
* notification to the queue, there is no need of calling any methods of the
* notification itself. Check the following example:
* @code
* JWindow window = new JWindow();
* Notification note = new Notification(window, WindowPosition.BOTTOMRIGHT, 25, 25, 1000);
* NotificationQueue queue = new NotificationQueue();
* queue.add(note);
* @endcode
* If there is no notifications in the queue, the notification is displayed
* right after the call of the #add() method. Otherwise, it will be queued
* until there is no notifications in display. Please note this is a simple
* <i>first in first out</i> queue, so no priorities are estabilished when
* adding notifications.
*
* @author Paulo Roberto Massa Cereda
* @version 1.3
* @since 1.3
*/
public class NotificationQueue implements ActionListener {
// a queue, a timer and a notification
private Queue<Notification> queue;
private Timer timer;
private Notification current;
/**
* Constructor method. Nothing new here, just instantiate
* the local attributes.
*/
public NotificationQueue() {
queue = new LinkedList<>();
timer = new Timer(50, this);
current = null;
}
/**
* Add the current notification to the queue system. If this is the
* only notification in the queue, it will probably be shown right away.
* Please check the following example:
* @code
* JWindow window = new JWindow();
* Notification note = new Notification(window, WindowPosition.BOTTOMRIGHT, 25, 25, 1000);
* NotificationQueue queue = new NotificationQueue();
* queue.add(note);
* @endcode
* @param notification The <b>net.sf.jcarrierpigeon.Notification</b>
* object.
*/
public synchronized void add(Notification notification) {
// check if queue is empty and there is no
// current notification
if (queue.isEmpty() && (current == null)) {
// show notification
current = notification;
current.animate();
}
else {
// there are other notifications, so we need to wait
queue.offer(notification);
// check if timer is not running
if (!timer.isRunning()) {
// start the timer
timer.start();
}
}
}
/**
* Implements the <code>ActionListener</code> for our timer. It will trigger
* notifications and process the queue.
* @param e The event.
*/
public void actionPerformed(ActionEvent e) {
// there is a current notification going on
if (current != null) {
// check if queue is not empty and there is no
// notification running
if ((!queue.isEmpty()) && (!current.isRunning())) {
// poll a notification from the queue
current = queue.poll();
// animate
current.animate();
}
else {
// if the queue is empty
if (queue.isEmpty()) {
// stop the timer
timer.stop();
}
}
}
}
}