source: trunk/src/org/expeditee/items/widgets/MemoryMonitor.java@ 919

/**
 *    MemoryMonitor.java
 *    Copyright (C) 2010 New Zealand Digital Library, http://expeditee.org
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.expeditee.items.widgets;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.JPanel;
import javax.swing.SwingUtilities;

import org.expeditee.items.ItemParentStateChangedEvent;
import org.expeditee.items.Text;

/**
 * A widget for displaying the heap space uasage at runtime
 * 
 * @author Brook Novak
 *
 */
public class MemoryMonitor extends InteractiveWidget {
        
        private long totalMemoryInBytes;
        private float currentMemoryUsage;
        private MonitorThread monitorThread = null;

        private static final Font USAGE_FONT = new Font("Arial", Font.BOLD, 12);
        

        public MemoryMonitor(Text source, String[] args) {
                super(source, new JPanel(), 40, 40, 40, 40);
                updateMemoryUsage();
        }
        
        @Override
        protected String[] getArgs() {
                return null;
        }
        
        private void updateMemoryUsage()
        {
                totalMemoryInBytes = Runtime.getRuntime().totalMemory();
                currentMemoryUsage =  (totalMemoryInBytes - Runtime.getRuntime().freeMemory()) / (float)totalMemoryInBytes;
                invalidateSelf();
        }
        
        @Override
        public void paint(Graphics g) {
                
                int height = getHeight();
                int width = getWidth();
                
                int memHeight = (int)(height * currentMemoryUsage);
                
                Color memColor;
                if (currentMemoryUsage > 0.8f) {
                        memColor = Color.RED;
                } else if (currentMemoryUsage > 0.5f) {
                        memColor = Color.ORANGE;
                } else  {
                        memColor = Color.GREEN;
                }
                
                g.setColor(memColor);
                g.fillRect(getX(), getY() + height - memHeight, width, memHeight);
                
                g.setColor(Color.WHITE);
                g.fillRect(getX(), getY(), width, height - memHeight);
                
                int percent = (int)(currentMemoryUsage * 100.0f);
                
                g.setColor(Color.BLACK);
                g.setFont(USAGE_FONT);
                g.drawString(percent + "%", getX() + 12, getY() + (height / 2) + 8);
                
                paintLink((Graphics2D)g);
        }


        @Override
        protected void onParentStateChanged(int eventType) {
                super.onParentStateChanged(eventType);

                switch (eventType) {
                case ItemParentStateChangedEvent.EVENT_TYPE_HIDDEN:
                case ItemParentStateChangedEvent.EVENT_TYPE_REMOVED:
                case ItemParentStateChangedEvent.EVENT_TYPE_REMOVED_VIA_OVERLAY:
                        if (monitorThread != null) {
                                monitorThread.destroy();
                                monitorThread = null;
                        } 
                        break;

                case ItemParentStateChangedEvent.EVENT_TYPE_ADDED:
                case ItemParentStateChangedEvent.EVENT_TYPE_ADDED_VIA_OVERLAY:
                case ItemParentStateChangedEvent.EVENT_TYPE_SHOWN:
                case ItemParentStateChangedEvent.EVENT_TYPE_SHOWN_VIA_OVERLAY:
                        if (monitorThread == null) {
                                monitorThread = new MonitorThread();
                                monitorThread.start();
                        }
                        break;
                        
                }

        }

        private class MonitorThread extends Thread
        {
                private MonitorGUIUpdator guiRunner = new MonitorGUIUpdator();

                public MonitorThread()
                {
                        setDaemon(true);
                }
                
                public void destroy()
                {
                        interrupt();
                }
                
                public void run()
                {
                        try {
                                while(!isInterrupted())
                                {
                                        SwingUtilities.invokeLater(guiRunner);
                                        sleep(5000);
                                }
                        } catch (InterruptedException e) {
                        }
                }
                
                private class MonitorGUIUpdator implements Runnable
                {
                        public void run()
                        {
                                updateMemoryUsage();
                        }
                }
        }
}