/**
* \cond LICENSE
* ********************************************************************
* This is a conditional block for preventing the DoxyGen documentation
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*
* JTelegraph - A message notification library
* Copyright (c) 2011, 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
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
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*
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* \endcond
*
* <b>Telegraph.java</b>: handles the display of message notifications.
* This class was created to act as a notification manager. Use this class
* together with the <code>net.sf.jtelegraph.Telegraph</code> class.
*/
package net.sf.jtelegraph;
// all needed imports
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 message notifications. This class was created to
* act as a message notification manager. Please note that this message
* notification manager handles the calls for methods of the
* <code>net.sf.jtelegraph.Telegraph</code> class. After adding a message
* notification to the queue, there is no need of calling any methods of the
* message notification itself. Check the following example:
* @code
* Telegraph telegraph = new Telegraph("Connection status", "The DB connection was established successfully", TelegraphType.NOTIFICATION_DONE, WindowPosition.BOTTOMLEFT, 4000);
* TelegraphQueue queue = new TelegraphQueue();
* queue.add(telegraph);
* @endcode
* If there is no notifications in the queue, the message 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 1.0
* @since 1.0
*/
public class TelegraphQueue implements ActionListener {
// a queue, a timer and a notification
private Queue<Telegraph> queue;
private Timer timer;
private Telegraph current;
/**
* Constructor method. Nothing new here, just instantiate
* the local attributes.
*/
public TelegraphQueue() {
queue = new LinkedList<>();
timer = new Timer(50, this);
current = null;
}
/**
* Add the current message 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
* Telegraph telegraph = new Telegraph("Connection status", "The DB connection was established successfully", TelegraphType.NOTIFICATION_DONE, WindowPosition.BOTTOMLEFT, 4000);
* TelegraphQueue queue = new TelegraphQueue();
* queue.add(telegraph);
* @endcode
* @param telegraph The telegraph itself. It must be an object of the
* <code>net.sf.jtelegraph.Telegraph</code> class.
*/
public synchronized void add(Telegraph telegraph) {
// check if queue is empty and there is no
// current notification
if (queue.isEmpty() && (current == null)) {
// show notification
current = telegraph;
current.animate();
}
else {
// there are other notifications, so we need to wait
queue.offer(telegraph);
// 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();
}
}
}
}
}