/*
 * @(#)MemoryMonitor.java	1.16 98/06/29
 *
 * Copyright 1998 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */


import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import com.sun.java.swing.JPanel;
import com.sun.java.swing.border.EtchedBorder;
import com.sun.java.swing.border.TitledBorder;


/**
 * Tracks Memory allocated & used, displayed in graph form.
 */
public class MemoryMonitor extends JPanel {

    public MemoryMonitorCanvas mmc;

    public MemoryMonitor() {
	setLayout(new BorderLayout());
	setBorder(new TitledBorder(new EtchedBorder(), "Memory Monitor"));
	mmc = new MemoryMonitorCanvas();
	add(mmc);
    }


    public class MemoryMonitorCanvas extends Canvas implements Runnable {
        Thread thread;
        int w, h;
        BufferedImage offImg;
        Graphics2D offG;
        Font font = new Font("Times New Roman", Font.PLAIN, 11);
        Runtime r = Runtime.getRuntime();
        int columnInc;
        int pts[];
        int num_pts;
	int ascent, descent;

        public MemoryMonitorCanvas() {
	    setBackground(Color.black);
	    start();
        }

        public Dimension getMinimumSize() {
	    return getPreferredSize();
        }

        public Dimension getMaximumSize() {
	    return getPreferredSize();
        }

        public Dimension getPreferredSize() {
	    return new Dimension(140,80);
        }


        public void paint(Graphics g) {

	    if (offG == null)
	        return;

            offG.setBackground(getBackground());
            offG.clearRect(0,0,w,h);

            float freeMemory = (float) r.freeMemory();
            float totalMemory = (float) r.totalMemory();

	    // .. Draw allocated and used strings ..
            offG.setColor(Color.green);
            offG.drawString(String.valueOf((int) totalMemory/1024) + "K allocated",  4.0f, (float) ascent+0.5f);
            offG.drawString(String.valueOf(((int) (totalMemory - freeMemory))/1024) + "K used", 4, h-descent);

	    // Calculate remaining size
	    float ssH = ascent + descent;
	    float remainingHeight = (float) (h - (ssH*2) - 0.5f);
	    float blockHeight = remainingHeight/10;
	    float blockWidth = 20.0f;
	    float remainingWidth = (float) (w - blockWidth - 10);

	    // .. Memory Free ..
	    offG.setColor(new Color(0, 100, 0));
	    int MemUsage = (int) ((freeMemory / totalMemory) * 10);
	    int i = 0;
	    for ( ; i < MemUsage ; i++) {
	        offG.fill(new Rectangle2D.Float(5,(float) ssH+i*blockHeight,
			        blockWidth,(float) blockHeight-1));
	    }

	    // .. Memory Used ..
            offG.setColor(Color.green);
	    for ( ; i < 10; i++)  {
	        offG.fill(new Rectangle2D.Float(5,(float) ssH+i*blockHeight,
			    blockWidth,(float) blockHeight-1));
	    }

	    // .. Draw History Graph ..
	    offG.setColor(new Color(46, 139, 87));
	    int graphX = 30;
	    int graphY = (int) ssH;
	    int graphW = w - graphX - 5;
	    int graphH = (int) remainingHeight;
	    Rectangle graphOutline = new Rectangle(graphX, graphY, graphW, graphH);
	    offG.draw(graphOutline);

	    int graphRow = graphH/10;

	    // .. Draw row ..
	    for (int j=graphY; j <= graphH+graphY;j+=graphRow)
	        offG.draw(new Line2D.Float(graphX,j,graphX+graphW,j));

	    // .. Draw animated column movement ..
	    int graphColumn = graphW/15;

	    if (columnInc == 0) columnInc = graphColumn;

	    for (int j=graphX+columnInc; j < graphW+graphX; j+= graphColumn)
	        offG.draw(new Line2D.Float(j,graphY,j,graphY+graphH));

	    --columnInc;

	    if (pts == null) {
	        pts = new int[graphW];
	        num_pts = 0;
	    } else {
	        offG.setColor(Color.yellow);
	        pts[num_pts] = (int) (graphY+ graphH * (freeMemory / totalMemory));
	        for (int j=graphX+graphW-num_pts, k = 0;k < num_pts; k++, j++) {
		    if (k != 0) {
		        if (pts[k] != pts[k-1])
	        	    offG.drawLine(j-1, pts[k-1], j, pts[k]);
		        else
	        	    offG.fillRect(j, pts[k], 1, 1);
		    }
	        }
	        if (num_pts+2 == pts.length) {
		    // throw out oldest point
		    for (int j = 1;j < num_pts; j++)
		        pts[j-1] = pts[j];
		    --num_pts;
	        } else
	            num_pts++;
	    }

            g.drawImage(offImg, 0, 0, this);
        }


        public void start() {
            thread = new Thread(this);
            thread.setPriority(Thread.MIN_PRIORITY);
	    thread.setName("MemoryMonitor");
            thread.start();
        }


        public synchronized void stop() {
            thread = null;
	    notify();
        }


        public void run() {

	    Thread me = Thread.currentThread();

            while (thread == me && !isShowing() || getSize().width == 0) {
	        try {
	            Thread.sleep(999);
	        } catch (InterruptedException e) { thread = null; return; }
	    }

            while (thread == me && isShowing()) {
	        if (getSize().width != w || getSize().height != h) {
                    w = getSize().width;
                    h = getSize().height;
                    offImg = (BufferedImage) createImage(w, h);
	            offG = offImg.createGraphics();
		    offG.setFont(font);
	    	    FontMetrics fm = offG.getFontMetrics(font);
	    	    ascent = (int) fm.getAscent();
	    	    descent = (int) fm.getDescent();
		}
		Graphics g = getGraphics();
		if (g == null)
		    continue;
		paint(g);
		g.dispose();
	        try {
	            thread.sleep(999);
	        } catch (InterruptedException e) { break; }
            }
	    thread = null;
        }
    }


    public static void main(String s[]) {
	WindowListener l = new WindowAdapter() {
	    public void windowClosing(WindowEvent e) {System.exit(0);}
	};
	Frame f = new Frame("Java 2D Demo - MemoryMonitor");
	f.addWindowListener(l);
	f.add("Center", new MemoryMonitor());
	f.pack();
	f.setSize(new Dimension(200,200));
	f.show();
    }
}