1.124J Foundations of Software Engineering

Problem Set 7 - Solution

Due Date: Thursday 11/2/00
 
The solution source code files are available in the 1.124 directory from where you can check them out using CVS. Please read and try to understand the solutions.

The solution source code files are in the source code repository directory /mit/1.124/src from where you can check them out to your directory using CVS.

To use CVS to check out any provided material from the 1.124 repository you first need to set the environment variable CVSROOT as below: (you can also put it in your .environment dotfile to avoid repetition)

% setenv CVSROOT /afs/athena.mit.edu/course/1/1.124/src

Then you can use either of the commands:

%  cvs co Problems/SOL7

% cvs co OOP_SOL7
(alias defined in 1.124/src/CVSROOT/modules)

Problem 1:[100%]

PoleSimulator.java

import javax.swing.*;
import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
import java.text.*;
import java.awt.geom.CubicCurve2D;
import java.net.*;
import java.io.*;
import java.util.*;

public class PoleSimulator extends JFrame
                           implements Runnable, ActionListener
{
    int frameNumber;
    long startTime ;
    int delay;
 Thread animatorThread;
    boolean frozen = true;

 int dx=500, dy=500;
 boolean dataFlag=false;

    JMenuBar menuBar ;
    JMenu fileMenu;
    JMenuItem importMI, exitMI;

 JToolBar toolBar;
 JButton startButton, stopButton, continueButton, resetButton ;
 JSeparator separator1, separator2, separator3;
 PolePanel polePanel;
 JPanel contentPane;

 PoleData poleData;
 

    public PoleSimulator(String str)
      {
  super(str);

  poleData = new PoleData();

  contentPane = new JPanel() ;
     contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));

  setMenuBar();

  setToolBar();

     setPolePanel();

     setContentPane(contentPane);

        pack();
     setVisible(true);

  setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);

  addWindowListener(new WindowAdapter()
                     {
                 public void windowClosing(WindowEvent e)
                         {
          dispose(); System.exit(0);
          }
                     }                     );

  }

 private void setMenuBar()
   {
       menuBar = new JMenuBar();

       fileMenu = new JMenu("File");
       menuBar.add(fileMenu);
       importMI = new JMenuItem("Import Data");
       importMI.addActionListener(this);
       fileMenu.add(importMI);
       exitMI = new JMenuItem("Exit");
       exitMI.addActionListener(this);
       fileMenu.add(exitMI);

    setJMenuBar(menuBar);
   }
 

 private void setToolBar()
   {
    toolBar = new JToolBar();

    startButton = new JButton(new ImageIcon("start.gif"));
    startButton.setMnemonic(KeyEvent.VK_S);
    startButton.setToolTipText("Start");
    startButton.setActionCommand("Start");
       startButton.addActionListener(this);
    startButton.setEnabled(false);
    startButton.setBackground(Color.gray);
    toolBar.add(startButton);

    separator1 = new JSeparator();
       separator1.setBackground(Color.black);
    toolBar.add(separator1);

    stopButton = new JButton(new ImageIcon("stop.gif"));
    stopButton.setMnemonic(KeyEvent.VK_B);
    stopButton.setToolTipText("Stop");
    stopButton.setActionCommand("Stop");
    stopButton.addActionListener(this);
       stopButton.setEnabled(false);
    stopButton.setBackground(Color.gray);
    toolBar.add(stopButton);

    separator2 = new JSeparator();
       separator2.setBackground(Color.black);
    toolBar.add(separator2);

       continueButton = new JButton(new ImageIcon("continue.gif"));
    continueButton.setMnemonic(KeyEvent.VK_C);
    continueButton.setToolTipText("Continue");
    continueButton.setActionCommand("Continue");
    continueButton.addActionListener(this);
       continueButton.setEnabled(false);
       continueButton.setBackground(Color.gray);
    toolBar.add(continueButton);

    separator3 = new JSeparator();
       separator3.setBackground(Color.black);
    toolBar.add(separator3);

    resetButton = new JButton(new ImageIcon("reset.gif"));
    resetButton.setMnemonic(KeyEvent.VK_R);
    resetButton.setToolTipText("Reset");
    resetButton.setActionCommand("Reset");
    resetButton.addActionListener(this);
       resetButton.setEnabled(false);
       resetButton.setBackground(Color.gray);
    toolBar.add(resetButton);

    contentPane.add(toolBar);
   }

private void setPolePanel()
  {
       polePanel = new PolePanel(poleData);
  polePanel.setMinimumSize(new Dimension(dx,dy-100));
  polePanel.setPreferredSize(new Dimension(dx,dy));

  contentPane.add(polePanel);
  }
 

   public void start()
      {
          if(!frozen)
            {
              if(animatorThread == null)
                 {
                   animatorThread = new Thread(this);
                 }
              animatorThread.start();
            }
       }
 

   public void stop()
        {
            animatorThread = null;
        }
 
 

   public void actionPerformed(ActionEvent e)
       {
          Object src = e.getSource();

          if(src == exitMI)
             System.exit(0);
       else if (src == importMI)
    readData();
       else if (src == startButton)
             startSimulation();
          else if(src == stopButton)
             stopSimulation();
          else if(src == continueButton)
             continueSimulation();
          else if(src == resetButton)
             resetSimulation();
          else if(src == exitMI)
             exitSimulation();
       }
 

   public void readData()
       {
      System.out.println("Getting the pole data");

   String file = "http://web.mit.edu/1.124/www/pole.data";

         int n = 0;

         try
          {
            URL url = new URL(file);
            Vector vT = new Vector();
      Vector vD = new Vector();;

            URLConnection connection = url.openConnection();
            InputStreamReader inStrReader = new InputStreamReader(connection.getInputStream());
            StreamTokenizer strTokenizer = new StreamTokenizer(inStrReader);

            while(strTokenizer.nextToken()!= strTokenizer.TT_EOF)
                {
                   n++;
                   vT.addElement(new Double((double)strTokenizer.nval));
                   strTokenizer.nextToken();
                   vD.addElement(new Double((double)strTokenizer.nval));
                }

      poleData.times = new double[n];
            poleData.displacements = new double[n];

   double t2, t1;
   poleData.maxDisplacement = 0.0;

      for(int i=0; i<n; i++)
       {
         poleData.times[i] = (new Double((vT.elementAt(i)).toString())).doubleValue();
         poleData.displacements[i] = (new Double((vD.elementAt(i)).toString())).doubleValue();
                  if(Math.abs(poleData.displacements[i]) > poleData.maxDisplacement)
         poleData.maxDisplacement = Math.abs(poleData.displacements[i]);
        }

   t2 = new Double((vT.elementAt(1)).toString()).doubleValue();
   t1 = new Double((vT.elementAt(0)).toString()).doubleValue();
      poleData.dt = t2 - t1;

            inStrReader.close();
   dataFlag =true;
   startButton.setEnabled(true);
           }
        catch(MalformedURLException e)
           {
             System.out.println(" MalformedURLException: " + e);
           }
        catch(IOException e)
           {
             System.out.println("IOException: " + e.getMessage());
           }

  System.out.println("\n  dt = " + poleData.dt);
  poleData.points = n;
        System.out.println("\n" + poleData.points + " values have been read");
     poleData.duration = poleData.points * poleData.dt;
     }
 

  public void startSimulation()
       {
       System.out.println("Starting the simulation");
    initializeSimulator();

          frozen = false;

          startButton.setEnabled(false);
          stopButton.setEnabled(true);
    continueButton.setEnabled(false);
          resetButton.setEnabled(false);

    start();
        }
 

  public void stopSimulation()
       {
       System.out.println("Stopping the simulation");
          frozen = true;

          startButton.setEnabled(false);
          stopButton.setEnabled(false);
    continueButton.setEnabled(true);
          resetButton.setEnabled(true);

          animatorThread = null;
        }
 

  public void continueSimulation()
       {
       System.out.println("Continuing the simulation");

          frozen = false;

          startButton.setEnabled(false);
          stopButton.setEnabled(true);
    continueButton.setEnabled(false);
          resetButton.setEnabled(false);

    start();
        }
 

   public void resetSimulation()
       {
          System.out.println("Simulation has been reset");

    frozen = true;
    poleData.step = 0;
    poleData.t = 0.0;

          startButton.setEnabled(false);
          stopButton.setEnabled(false);
    continueButton.setEnabled(false);
          resetButton.setEnabled(false);

    if(dataFlag)
    startButton.setEnabled(true);

    polePanel.repaint();
          animatorThread = null;
        }
 

 public void exitSimulation()
   {
          System.out.println("Exiting the program....");
    System.exit(0);
   }
 

    public void run()
       {
         Thread.currentThread().setPriority(Thread.MIN_PRIORITY);

         startTime = System.currentTimeMillis();
   delay = (int)(1000.0 * poleData.dt);

         while(Thread.currentThread() == animatorThread
            &&  (frameNumber<=poleData.points) )
             {
               repaint();

                try
                  {
                    startTime += delay;
                    Thread.sleep(Math.max(0, startTime-System.currentTimeMillis()));
                   }
    catch(InterruptedException e)
                   {
       break;
       }
    poleData.times[poleData.step] = poleData.t;

    poleData.t += poleData.dt;
                poleData.step = frameNumber++;
              }
 

   if(frameNumber > poleData.points)
        {
              startButton.setEnabled(false);
              stopButton.setEnabled(false);
        continueButton.setEnabled(false);
              resetButton.setEnabled(true);
     poleData.step = 0;
        }
        }
 

  private void initializeSimulator()
     {
     poleData.t = 0.0;
  frameNumber = 0;
  }
 

   public static void main(String args[])
    {
       new PoleSimulator("Pole Simulator");
    }

}
 
 

PolePanel.java

import javax.swing.*;
import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
import java.text.*;
import java.awt.geom.CubicCurve2D;

public class PolePanel extends JPanel
{
 CubicCurve2D.Double column;

 int xb, yb, ctrXb, ctrYb;
 int xt, yt, ctrXt, ctrYt;
 int baseX, baseY, baseWidth, baseHeight;
    final static BasicStroke columnStroke = new BasicStroke(5.0f);

 DecimalFormat df1 = new DecimalFormat("#0.##");
 DecimalFormat df2 = new DecimalFormat("#0.####");
 PoleData poleData = null;

    public PolePanel(PoleData d)
      {
   super();
   setBackground(Color.white);
   setForeground(Color.black);
   poleData = d;
   }
 

     public void paintComponent(Graphics g)
    {
   super.paintComponent(g);
         Graphics2D g2 = (Graphics2D) g;
         g2.setStroke(columnStroke);

   xb = ctrXb = (int) (0.5 * getWidth());
   yb = (int) (0.7 * getHeight());
   yt = (int) (0.2 * getHeight());
   ctrYb = (int) (0.6 * getHeight());
   ctrYt = (int) (0.2 * getHeight());

   baseX = (int) (0.1 * getWidth());
   baseWidth = (int) (0.8 * getWidth());
   baseY = (int) (0.7 * getHeight());
   baseHeight = (int) (0.1 * getHeight());

   xt = ctrXt = (int) (0.5 * getWidth()) ;

   if(poleData!=null && poleData.step>0)
       xt = ctrXt = (int) (0.5 * getWidth() + 0.2*getWidth()*
      poleData.displacements[poleData.step] /
   poleData.maxDisplacement);

         column = new CubicCurve2D.Double(xb, yb, ctrXb, ctrYb,
            ctrXt, ctrYt, xt, yt);
   g2.draw(column);

   g2.fillRect(baseX, baseY, baseWidth, baseHeight);

   if(poleData!=null && poleData.step>0)
     {
      g2.drawString("Time = " + df1.format(poleData.t),
                       (int) (0.2 * getWidth()),
                       (int) (0.90 * getHeight()));

      g2.drawString("Duration = " + df1.format(poleData.duration),
                        (int) (0.2 * getWidth()),
                        (int) (0.95 * getHeight()));

      g2.drawString("Displacement = " +
        df2.format(poleData.displacements[poleData.step]),
                       (int) (0.6 * getWidth()),
                       (int) (0.90 * getHeight()));

      g2.drawString("Max displacement = " + df2.format(poleData.maxDisplacement),
                        (int) (0.6 * getWidth()),
                        (int) (0.95 * getHeight()));
   }
  }

}
 
 

PoleData.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class PoleData
{
 double times[]=null, displacements[]=null;
 double maxDisplacement;
    double t, dt, duration;
 int step, points;

    PoleData()
     {
  times = null;
  displacements = null;
        maxDisplacement = 0.0;
  step = 0;
  points = 0;
  t =0.0;
  dt = 0.0;
  duration = 0.0;
     }
}



© 1.124J Foundations of Software Engineering
Prof. Kevin Amaratunga,1-274, kevina@mit.edu
Prof. John R. Williams,  1-250, jrw@mit.edu
TA: Petros Komodromos, 1-245, petros@mit.edu