/**
 * MemoryStatus.java runs a background process that sleeps for a
 * pre-determined amount of time. When it awakens, it displays
 * current memory usage in a "ticker-tape" display window.
 *
 * This is closely based on StatusMemory.java by Jef Poskanzer, from
 * his public distribution on <http://www.acme.com>
 *
 * Copyright &copy; 1996-1998 Martin Minow. All Rights Reserved.<p>
 *
 * Permission to use, copy, modify, and redistribute this software and its
 * documentation for personal, non-commercial use is hereby granted provided that
 * this copyright notice and appropriate documentation appears in all copies. This
 * software may not be distributed for fee or as part of commercial, "shareware,"
 * and/or not-for-profit endevors including, but not limited to, CD-ROM collections,
 * online databases, and subscription services without specific license.<p>
 *
 * @author <a href="mailto:minow@apple.com">Martin Minow</a>
 * @version 1.0
 * Set tabs every 4 characters.
 */
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.lang.*;

public class MemoryStatusInfo extends Panel
{
	private static final int		totalKIndex			= 0;
	private static final int		usageKIndex			= 1;
	private static final int		perSecIndex			= 2;
	private static final int		labelCount			= 3;
	private static final String		labelString		= "Total\nUsage\nKB/Sec\n";
	private Label[]					valueLabels		= new Label[labelCount];
	private Label[]					valueData		= new Label[labelCount];
	
	/*
	 * Here are the values we display.
	 */
	private transient int			totalK				= Integer.MIN_VALUE;
	private transient int			usageK				= Integer.MIN_VALUE;
	private transient double		usageKBytesPerSec	= Double.MIN_VALUE;
	
	public MemoryStatusInfo()
	{
		setBackground(Color.white);
		GridBagLayout			gridbag = new GridBagLayout();
		setLayout(gridbag);
		StringTokenizer t = new StringTokenizer(labelString, "\n");
		for (int i = 0; t.hasMoreElements(); i++) {
			initializeLabel(i, t.nextToken());
		}
		Canvas line				= new Canvas();
		/*
		 * Add a vertical line to the right of the text as a separator
		 * between the info and the ticker-tape.
		 */
		line.setBackground(Color.black);
		line.resize(1, 1);
		GridBagConstraints c	= new GridBagConstraints();
		c.gridx					= 2;
		c.gridy					= 0;
		c.gridwidth				= 1;
		c.gridheight			= labelCount + 1;
		c.fill					= GridBagConstraints.VERTICAL;
		c.anchor				= GridBagConstraints.WEST;
		c.weightx				= 0.0;
		c.weighty				= 1.0;
		c.insets			 	= new Insets(0, 0, 0, 0);
		gridbag.setConstraints(line, c);
		add(line);
		/*
		 * Add a blank panel that fills the space below the data.
		 * (well, that's the idea, anyway).
		 */
		Panel blank				= new Panel();
		c.gridx					= 0;
		c.gridy					= labelCount;
		c.gridwidth				= 2;
		c.gridheight			= 1;
		c.fill					= GridBagConstraints.BOTH;
		c.anchor				= GridBagConstraints.CENTER;
		c.weightx				= 1.0;
		c.weighty				= 1.0;
		gridbag.setConstraints(blank, c);
		add(blank);
		setValues(0, 0, 0.0);
	}
	private void initializeLabel(
			int				row,
			String			label
		)
	{
		valueLabels[row]		= new Label(label, Label.LEFT);
		valueData[row]			= new Label("-00.000", Label.RIGHT);
		GridBagConstraints c	= new GridBagConstraints();
		c.gridx					= 0;
		c.gridy					= row;
		c.gridwidth				= 1;
		c.gridheight			= 1;
		c.fill					= GridBagConstraints.NONE;
		c.anchor				= GridBagConstraints.WEST;
		c.weightx				= 0.0;
		c.weighty				= 0.0;
		c.insets			 	= new Insets(0, 0, 0, 0);
		GridBagLayout gridbag	= (GridBagLayout) getLayout();
		gridbag.setConstraints(valueLabels[row], c);
		add(valueLabels[row]);
		c.gridx					= 1;
		c.anchor				= GridBagConstraints.EAST;
		gridbag.setConstraints(valueData[row], c);
		add(valueData[row]);
	}
	/*
	 * Update the label values.
	 */
	public void setValues(
			int				totalK,
			int				usageK,
			double			usageKBytesPerSec
		)
	{
		if (this.totalK != totalK) {
			this.totalK			= totalK;
			valueData[totalKIndex].setText(Integer.toString(totalK));
		}
		if (this.usageK != usageK) {
			this.usageK			= usageK;
			valueData[usageKIndex].setText(Integer.toString(usageK));
		}
		if (this.usageKBytesPerSec != usageKBytesPerSec) {
			this.usageKBytesPerSec = usageKBytesPerSec;
			StringBuffer	text	= new StringBuffer();
			if (usageKBytesPerSec < 0) {
				text.append('-');
				usageKBytesPerSec	= (-usageKBytesPerSec);
			}
			long	intPart	= (long) (usageKBytesPerSec + 0.5);
			int		fract	= (int) ((usageKBytesPerSec - ((double) intPart)) * 1000.0);
			text.append(Long.toString(intPart) + Integer.toString(fract + 1000));
			text.setCharAt(text.length() - 4, '.');
			valueData[perSecIndex].setText(text.toString());
		}
	}
}