Trajectory

Question

ee my program implementation @ the following:
http://home.comcast.net/~weldonchafinjr/wsb/html/view.cgi-home.html-.html
using TRAJECTORY PROGRAM link
or
http://home.comcast.net/wsb-cgi-bin/ssi.cgi?PWPTool=HTMLView&State=False&wsbID=257896&GroupID=228536&Owner=weldonchafinjr&SiteID=1297966
or
http://home.comcast.net/~weldonchafinjr/wsb/trajectory/Trajectory.html
The program set is not allowed to have inner classes and is comprised of five classes and the html file:
Trajectory.class :      Trajectory.java has 1135 LOC in castrated version
SimulationPanel.class:      SimulationPanel.java has 152 LOC
Are.class:     Are.java has 7 LOC
Tare.class      Tare.class has 7 LOC
Nve.class      Nve.class has 7 LOC
Trajectory.html      Trajectory.html has 11 LOC
Trajectory.class extends JApplet implements ActionListener
SimulationPanel.class extends JPanel used in Trajectory.class
Are.class., Tare.class, Nve.class each extends Exception class
Trajectory.html is a basic html file
Trajectory.class creates a GUI for user I/O, calculates data and creates a timer to set up an array of the data. SimulationPanel then uses array data to invoke paintComponent( Graphics g ) method and plot the data. Simulation Panel sets up a 2D real time simulation display.
The program set works fine via appletviewer Trajectory.html command.
However, invoking the html file directly causes a problem. When the Simulation Panel display is generated, I am unable to use its reset button to perform another 2D Simulation. The scale for the 2D Simulation is frozen and the applet seems to encounter deadlock. So I have added the information messages via showMessageDialog to warn users of this problem. I saw the Sunmicrosystems demo program "DitherTest.java" code and noticed how threads were controlled with a wipe operation via a "New Image" button and I wonder if my Simulation Panel reset button could be modified to do something similar. I do not presently have any elaborate overrides for thread control methods.
I desire assistance in correcting this problem. The castrated version essentially is the same as what is currently used at the website except some methods and variable values have been modified for security reasons but otherwise are not relevant to the problem. I suspect that not much code modification will be necessary and I don't think modifications to Are.java, Tare.java and Nve.java are required.
The solution could actually be relatively simple, but I don't have an IDE to troubleshoot. If the total LOC are not too much to post here, then let me know and I'll post. Otherwise, give me an Email address and I'll convey the code.

Answer 1

The following code set is the castrated version. Don't get frightened by the amount of code since the majority is commenting and methods dedicated to the calculation and GUI that are not a part of the problem. Who can help me?
Trajectory.java:
// Trajectory Analysis Program: Trajectory.java
//VERSION T1
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
public class Trajectory extends JApplet implements ActionListener {
     final double MAX = 90.0;
     final double MIN = -90.0;
     final double MAX_ALTITUDE = 2000000.0;
     final double MIN_ALTITUDE = 0.0;
     final double R = 20925643.2;               // earth radius ft
     final double G_SL = 32.174;               // gravity accel: sea lvl (fps)ps
     final double DENSITY_SL = 0.002376899341;     // air dens: sea lvl slugs/cu ft
     final double TEMP_SL = 518.69;               // air temp: sea lvl Rank
     final double PRESS_SL = 2116.199414;          // air press: sea lvl psf
     final static int MAX_TIME = 6000;
     private JTextArea introductionArea, resultsArea;
     private JLabel spanLabel, chordLabel,
          thicknessLabel, massLabel, altitudeLabel, altitude_endLabel, velocityLabel,
          trajectory_angleLabel, time_incrementLabel, rotation_factorLabel,
          calculationLabel, resultsLabel;
     private JTextField spanField, chordField, thicknessField,
          massField, altitudeField, altitude_endField, velocityField,
          trajectory_angleField, time_incrementField, rotation_factorField;
     private JButton startButton, resetButton;
     public JButton two_d_sButton, calcButton, simstartButton, simresetButton;
     double max_alt, max_dis;
     String introduction_string, span_string, chord_string, thickness_string,
          mass_string, altitude_string, altitude_end_string, velocity_string,
          trajectory_angle_string, time_increment_string, rotation_factor_string,
          results_string;
     public String data_area_string;
     public JTextArea data_area;
     public double span, chord, thickness, mass, altitude, altitude_end, velocity,
          trajectory_angle, time_increment, rotation_factor, distance, velocity_fps,
          elapsed_time, temp_Rank, viscosity, density, orbit_dbl, new_distance,
          c_miles, d_min, sec, Joules, Tons_of_TNT, Pounds_of_TNT,
          KiloTons_of_TNT, Hiroshima_Bomb, angleB;
     public boolean value, sentinel, status_2, loop;
     public int orbit, min;
     public static int time_counter, m, n;
     public static double Results_Array[][] = new double[MAX_TIME][6];
     public static boolean scale_type = true;
     public static boolean animate = false;
     public static int max_screen_altitude_scale, max_screen_distance_scale;
     private CardLayout layout = new CardLayout();
     SimulationPanel mSimPanel;
     public static int resultsRIndex = 0;
     public static boolean erase = true;
     public int time_count = 0;
     public int RIndex = 0;
     Timer mAnimationTimer;
     int mCurrentPoint;
      * This main() method allows the applet to be run as a command line application.
      * Please leave it in for future debugging.
      * Use the command line: java Trajectory
     public static void main(String[] args) {
          JFrame mainFrame = new JFrame("Trajectory Simulation");
          mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          Trajectory traj = new Trajectory();
          traj.init();
          mainFrame.getContentPane().add(traj, BorderLayout.CENTER);
          mainFrame.pack();
          traj.start();
          mainFrame.setVisible(true);
     // create objects
     public void init()
          span = 0;
          chord = 0;
          thickness = 0;
          mass = 0;
          altitude = 0;
          altitude_end = 0;
          velocity = 0;
          trajectory_angle = 0;
          time_increment = 0;
          rotation_factor = 0;
          distance = 0;
          velocity_fps = 0;
          elapsed_time = 0;
          temp_Rank = 0;               //     air temperature degrees R
          viscosity = 0;               //     air viscosity     
          density = 0;               //     air density
          value = true;
          sentinel = true;
          boolean status_2 = true;     //     short cut condition
          loop = true;
          orbit = 0;
          orbit_dbl = 0.0;
          new_distance = 0.0;
          c_miles = 0.0;
          d_min = 0.0;
          min = 0;
          sec = 0.0;
          Joules = 0.0;
          Tons_of_TNT= 0.0;
          Pounds_of_TNT= 0.0;           
          KiloTons_of_TNT= 0.0;
          Hiroshima_Bomb= 0.0;
          angleB = 0;
          max_dis = 0;
          max_screen_altitude_scale = 0;
          max_screen_distance_scale = 0;
          mCurrentPoint = 0;
          time_counter = 0;
          m = 0;
          n= 0;
          for( m = 0; m < MAX_TIME; m++ )
               for( n = 0; n < 6; n++ )
                    Results_Array[m][n] = 0;
          Introduction();
          span_string = "";
          chord_string = "";
          thickness_string = "";
          mass_string = "";
          altitude_string = "";
          altitude_end_string = "";
          velocity_string = "";
          trajectory_angle_string = "";           
          time_increment_string = "";
          rotation_factor_string = "";
          results_string = "";
          // create container & panel
          this.getContentPane().setLayout(this.layout);
                   JPanel panelA = new JPanel();
          two_d_sButton = new JButton("2D Simulation");
          // register two_d_sButton event handler
          two_d_sButton.addActionListener(this);
          this.getContentPane().add(panelA, "Calculation");
          panelA.setLayout(new BorderLayout());
          // set up vertical boxlayout
          Box box = Box.createVerticalBox();
          Box inputbox1 = Box.createHorizontalBox();
          Box inputbox2 = Box.createHorizontalBox();
          Box inputbox2a = Box.createHorizontalBox();
          Box inputbox2b = Box.createHorizontalBox();
          Box inputbox2c = Box.createHorizontalBox();
          Box inputbox2d = Box.createHorizontalBox();
          Box inputbox3 = Box.createHorizontalBox();
          Box buttonbox = Box.createHorizontalBox();
          // set up introduction
          introductionArea = new JTextArea( introduction_string, 21, 50 );
          introductionArea.setEditable( false );
          box.add( new JScrollPane( introductionArea ) );
          box.add( Box.createVerticalStrut (10) );
          box.add( inputbox1);
          box.add(inputbox2a);
          Dimension minSize = new Dimension(5, 15);
          Dimension prefSize = new Dimension(5, 15);
          Dimension maxSize = new Dimension(Short.MAX_VALUE, 15);
          inputbox2a.add(new Box.Filler(minSize, prefSize, maxSize));
          // set up span
          spanLabel = new JLabel( "span (feet)" );
          spanField = new JTextField(5 );
          inputbox2a.add( spanLabel );
          inputbox2a.add( spanField );
          inputbox2a.add(new Box.Filler(minSize, prefSize, maxSize));
          // set up chord
          chordLabel = new JLabel( "chord (feet)" );
          chordField = new JTextField(5 );
          inputbox2a.add( chordLabel );
          inputbox2a.add( chordField );
          inputbox2a.add(new Box.Filler(minSize, prefSize, maxSize));
          // set up thickness
          thicknessLabel = new JLabel( "thickness (feet)" );
          thicknessField = new JTextField(5 );
          inputbox2a.add( thicknessLabel );
          inputbox2a.add( thicknessField );
          inputbox2a.add(new Box.Filler(minSize, prefSize, maxSize));
          box.add( Box.createVerticalStrut (10) );
          box.add(inputbox2b);
          inputbox2b.add(new Box.Filler(minSize, prefSize, maxSize));
          // set up mass
          massLabel = new JLabel( "mass (slugs)" );
          massField = new JTextField(5);
          inputbox2b.add( massLabel );
          inputbox2b.add( massField );
          inputbox2b.add(new Box.Filler(minSize, prefSize, maxSize));
          // set up start altitude
          altitudeLabel = new JLabel( "start altitude (feet)");
          altitudeField = new JTextField(5 );
          inputbox2b.add( altitudeLabel );
          inputbox2b.add( altitudeField );
          inputbox2b.add(new Box.Filler(minSize, prefSize, maxSize));
          // set up end altitude
          altitude_endLabel = new JLabel( "end altitude (feet)");
          altitude_endField = new JTextField(5 );
          inputbox2b.add( altitude_endLabel );
          inputbox2b.add( altitude_endField );
          inputbox2b.add(new Box.Filler(minSize, prefSize, maxSize));
          box.add( Box.createVerticalStrut (10) );
          Dimension minSize2c = new Dimension(35, 15);
          Dimension prefSize2c = new Dimension(35, 15);
          Dimension maxSize2c = new Dimension(Short.MAX_VALUE, 15);
          box.add(inputbox2c);
          inputbox2c.add(new Box.Filler(minSize2c, prefSize2c, maxSize2c));
          // set up velocity
          velocityLabel = new JLabel( "velocity (Mach Number)");
          velocityField = new JTextField(5);
          inputbox2c.add( velocityLabel );
          inputbox2c.add( velocityField );
          inputbox2c.add(new Box.Filler(minSize2c, prefSize2c, maxSize2c));
          // set up trajectory_angle
          trajectory_angleLabel = new JLabel( "trajectory angle (degrees)");
          trajectory_angleField = new JTextField(5);
          inputbox2c.add( trajectory_angleLabel );
          inputbox2c.add( trajectory_angleField );
          inputbox2c.add(new Box.Filler(minSize2c, prefSize2c, maxSize2c));
          box.add( Box.createVerticalStrut (10) );
          Dimension minSize2d = new Dimension(50, 15);
          Dimension prefSize2d = new Dimension(50, 15);
          Dimension maxSize2d = new Dimension(Short.MAX_VALUE, 15);
          box.add(inputbox2d);
          inputbox2d.add(new Box.Filler(minSize2d, prefSize2d, maxSize2d));
          // set up time_increment
          time_incrementLabel = new JLabel( "time increment (seconds)" );
          time_incrementField = new JTextField(5);
          inputbox2d.add( time_incrementLabel );
          inputbox2d.add( time_incrementField );
          inputbox2d.add(new Box.Filler(minSize2d, prefSize2d, maxSize2d));
          // set up rotation_factor
          rotation_factorLabel = new JLabel( "rotation factor (number)" );
          rotation_factorField = new JTextField(5);
          inputbox2d.add( rotation_factorLabel );
          inputbox2d.add( rotation_factorField );
          inputbox2d.add(new Box.Filler(minSize2d, prefSize2d, maxSize2d));
          box.add( Box.createVerticalStrut (10) );
          Dimension minSizeB = new Dimension(10, 30);
          Dimension prefSizeB = new Dimension(10, 30);
          Dimension maxSizeB = new Dimension(Short.MAX_VALUE, 30);
          buttonbox.add(new Box.Filler(minSizeB, prefSizeB, maxSizeB));
          // set up start button
          startButton = new JButton( "START" );
          buttonbox.add( startButton );
          buttonbox.add(new Box.Filler(minSizeB, prefSizeB, maxSizeB));
          // set up reset button
          resetButton = new JButton( "RESET" );
          buttonbox.add( resetButton );
          buttonbox.add(new Box.Filler(minSizeB, prefSizeB, maxSizeB));
          // set up 2D Simulation button
          buttonbox.add(two_d_sButton);
          buttonbox.add(new Box.Filler(minSizeB, prefSizeB, maxSizeB));
          box.add( Box.createVerticalStrut (10) );
          box.add( buttonbox);
          // set up results
          resultsArea = new JTextArea( results_string, 9, 50 );
          resultsArea.setEditable( false );
          box.add( new JScrollPane( resultsArea ) );
          // add box to panelA
          panelA.add( box);
          // register event handlers
          spanField.addActionListener( this );
          chordField.addActionListener( this );          
          thicknessField.addActionListener( this );
          massField.addActionListener( this );
          altitudeField.addActionListener( this );
          altitude_endField.addActionListener( this );
          velocityField.addActionListener( this );          
          trajectory_angleField.addActionListener( this );
          time_incrementField.addActionListener( this );
          rotation_factorField.addActionListener( this );
          startButton.addActionListener( this );
          resetButton.addActionListener( this );
          reset();
     } // end method init     
     public void t_r_a_test (double trajectory_angle) throws Tare {   
          if (trajectory_angle > MAX || trajectory_angle < MIN)
                      throw new Tare("\ntrajectory_angle "
               + trajectory_angle + " is outside of allowable range\n" 
               + "( " + MIN + " <= trajectory angle <= " + MAX + " )\n\n"
               + "Try different values for inputs.\n"
               + "First consider a smaller time increment.\n"
               + "Other considerations should include using \n"
               + "a different altitude, trajectory angle or lesser velocity.\n"
               + "Several types of changes in input values "
               + "can resolve this problem.");
          if (trajectory_angle > MAX || trajectory_angle < MIN)
               sentinel = false;
     }  // end method t_r_a_test
     public void a_r_e_test (double altitude) throws Are {   
          if ( altitude > MAX_ALTITUDE )     
                      throw new Are("\naltitude "
               + altitude + " is outside of allowable range\n\n" 
               + "( " + MIN_ALTITUDE + " <= altitude <= "
               + MAX_ALTITUDE + " )\n\n"
               + "Try different values for inputs.\n"
               + "First consider a smaller time increment.\n"
               + "Other considerations should include using \n"
               + "a different altitude, trajectory angle or lesser velocity.\n"
               + "Several types of changes in input values "
               + "can resolve this problem.");
               if ( altitude > MAX_ALTITUDE )     
                    sentinel = false;
     }  // end method a_r_e_test
     public void n_v_test (boolean value) throws Nve {   
          if ( value == false ){
               if( span < 0 ){
                     span = 0;
                           throw new Nve("\nValue for "
                    + " span must not be negative\n\n" 
                    + "Try another value ");
               if( chord < 0 ){
                     chord = 0;
                           throw new Nve("\nValue for "
                    + " chord must not be negative\n\n" 
                    + "Try another value ");
               if( thickness < 0 ){
                     thickness = 0;
                           throw new Nve("\nValue for "
                    + " thickness must not be negative\n\n" 
                    + "Try another value ");
               if( mass < 0 ){
                     mass = 0;
                           throw new Nve("\nValue for "
                    + " mass must not be negative\n\n" 
                    + "Try another value ");
               if( altitude < 0 ){
                    altitude = 0;
                           throw new Nve("\nValue for "
                    + " start altitude must not be negative\n\n" 
                    + "Try another value ");
               if( altitude_end < 0 ){
                    altitude_end = 0;
                           throw new Nve("\nValue for "
                    + " end altitude must not be negative\n\n" 
                    + "Try another value ");
               if( velocity < 0 ){
                    velocity = 0;
                           throw new Nve("\nValue for "
                    + " velocity must not be negative\n\n" 
                    + "Try another value ");
               if( time_increment < 0 ){
                    time_increment = 0;
                           throw new Nve("\nValue for "
                    + " time increment must not be negative\n\n" 
                    + "Try another value ");
               if( rotation_factor < 0 ){
                    rotation_factor = 0;
                           throw new Nve("\nValue for "
                    + " rotation factor must not be negative\n\n" 
                    + "Try another value ");
          } //end if( value == false )
     }  // end method n_v_test
     // process events
     public void actionPerformed( ActionEvent event )
          // process spanField
          if( event.getSource() == spanField ) {
               span_string = spanField.getText();
               span = Double.parseDouble( span_string);
          // process chordField
          if( event.getSource() == chordField ) {
               chord_string = chordField.getText();
               chord = Double.parseDouble( chord_string);
          // process thicknessField
          if( event.getSource() == thicknessField ) {
               thickness_string = thicknessField.getText();
               thickness = Double.parseDouble( thickness_string);
          // process massField
          if( event.getSource() == massField ) {
               mass_string = massField.getText();
               mass = Double.parseDouble( mass_string);
          // process altitudeField
          if( event.getSource() == altitudeField ){
               altitude_string = altitudeField.getText();
               altitude = Double.parseDouble( altitude_string);
          // process altitude_endField
          if( event.getSource() == altitude_endField ){
               altitude_end_string = altitude_endField.getText();
               altitude_end = Double.parseDouble( altitude_end_string);
          // process trajectory_angleField
          if( event.getSource() == trajectory_angleField ){
               trajectory_angle_string = trajectory_angleField.getText();
               trajectory_angle = Double.parseDouble( trajectory_angle_string);
          // process time_incrementField
          if( event.getSource() == time_incrementField ){
               time_increment_string = time_incrementField.getText();
               time_increment = Double.parseDouble( time_increment_string);
          // process velocityField
          if( event.getSource() == velocityField ){
               velocity_string = velocityField.getText();
               velocity = Double.parseDouble( velocity_string);
          // process rotation_factorField
          if( event.getSource() == rotation_factorField ){
               rotation_factor_string = rotation_factorField.getText();
               rotation_factor = Double.parseDouble( rotation_factor_string);
          // process startButton event
          if ( event.getSource() == startButton )
               if( altitude > MAX_ALTITUDE)
                    reset();
               strtb();
          // process resetButton event
          if ( event.getSource() == resetButton )
               reset();
          // process two_d_sButton
          if( event.getSource() == two_d_sButton )
               Trajectory.this.layout.next(Trajectory.this.getContentPane());
               String options = "After you perform a simulation you must terminate "
                         + "by using browser back button.\n"
                         + "Then, you can begin a new simulation by "
                         + "mouse clicking the Trajectory Program link again.";
               JOptionPane.showMessageDialog( null, options);
          // process calcButton
          if( event.getSource() == calcButton )
               Trajectory.this.layout.previous(Trajectory.this.getContentPane());
          // process simstartButton event
          if ( event.getSource() == simstartButton )
               strtsim();
          // process simresetButton event
          if ( event.getSource() == simresetButton )
               resetsim();
          // process a tick from the animation timer
          if (event.getSource() == mAnimationTimer) {
               mCurrentPoint++;
               data_area.setText( get_data() );
               mSimPanel.repaint();
     } // end method actionPerformed
     public String get_data(){
          int index;
          index = mCurrentPoint;
          if(mCurrentPoint >=  time_counter )
               index = time_counter;
          String time_string = "";
          String dist_string = "";
          int min = 0;
          int sec = 0;
          int fdist = 0;
          int mdist = 0;
          min = (int)Results_Array[ index ][ 0 ] / 60;
          sec = (int)Results_Array[ index ][ 0 ] - (min  * 60);
          mdist = (int)Results_Array[ index ][ 2 ];
          fdist = (int)Results_Array[ index ][ 5 ] - (mdist * 5280);
          if((int)Results_Array[ index ][ 0 ] < 60 )
               time_string = (int)Results_Array[ index ][ 0 ]  + " sec" ;
          else
               time_string = min +  " min + " + sec + " sec" ;
          if((int)Results_Array[ index ][ 5 ] < 5280 )
               dist_string = (int)Results_Array[ index ][ 5 ] + " feet";
          else
               dist_string = mdist + " miles + " + fdist + " feet";
          data_area_string = "Elapsed Time:  " + time_string
               + "\tDistance: " + dist_string
               + "\tAltitude: " + (int)Results_Array[ index ][ 1 ]  + " feet\n"
               + "Velocity: " + (int)Results_Array[ index ][ 3 ]  + " fps"
               + "\t\tTrajectory Angle: " + (int)Results_Array[ index ][ 4 ]  + " degrees";
          return data_area_string;
     }  // end method get_data
     public void strtsim(){
          time_count = getPointCount(time_counter);
          erase = true;
          animate = true;
          int delay = 1000;
          mCurrentPoint = 0;
          mAnimationTimer = new Timer(delay, this);
          mAnimationTimer.start();
     } // end method strtsim
      * Returns the current point to be displayed in any ongoing animation.
     public Point getCurrentAnimationPoint() {
          if(scale_type)
               return new Point((int)Results_Array[mCurrentPoint][2], (int)Results_Array[mCurrentPoint][1]);
          else
               return new Point((int)Results_Array[mCurrentPoint][5], (int)Results_Array[mCurrentPoint][1]);
     public void resetsim(){
          mAnimationTimer.stop();
          animate = false;
          data_area_string = "";
          data_area.setText( data_area_string );
          reset();
          System.gc();
          System.runFinalization();
     } // end method resetsim
     public int getPointCount(int time_counter_value){
          int point_count = 0;
          point_count = time_counter_value + 1;
          return point_count;
     public void strtb()
          try{          
               span = Double.parseDouble( spanField.getText() );
               chord = Double.parseDouble( chordField.getText() );
               thickness = Double.parseDouble( thicknessField.getText() );
               mass = Double.parseDouble( massField.getText() );
               altitude = Double.parseDouble( altitudeField.getText());
               altitude_end = Double.parseDouble( altitude_endField.getText());
               velocity = Double.parseDouble( velocityField.getText());
               trajectory_angle = Double.parseDouble( trajectory_angleField.getText());
               time_increment = Double.parseDouble( time_incrementField.getText() );     
               rotation_factor = Double.parseDouble( rotation_factorField.getText() );          
               // test input
               if( span < 0 || chord < 0 || thickness < 0 || mass < 0
                    || altitude < 0 || altitude_end < 0 || velocity < 0
                    || time_increment < 0 || rotation_factor < 0 )
               value = false;
               t_r_a_test( trajectory_angle );
               n_v_test( value );
               a_r_e_test( altitude );
               // calculate trajectory     
               calculate( );
               impact_energy_calc();
               // set up panelB
               mSimPanel = new SimulationPanel(this, 0, max_screen_distance_scale, 0, max_screen_altitude_scale);               
               mSimPanel.setLayout(new FlowLayout());
               // set up sim box & simbox2
               Box simbox = Box.createHorizontalBox();
               Box simbox2 = Box.createHorizontalBox();
               Dimension minSizesim = new Dimension(10, 30);
               Dimension prefSizesim = new Dimension(10, 30);
               Dimension maxSizesim = new Dimension(Short.MAX_VALUE, 30);
               simbox.add(new Box.Filler(minSizesim,prefSizesim,maxSizesim) );
               simstartButton = new JButton ( "START" );
               simbox.add( simstartButton );
               simbox.add(new Box.Filler(minSizesim,prefSizesim,maxSizesim) );
               simresetButton = new JButton ( "RESET" );
               simbox.add( simresetButton );
               simbox.add(new Box.Filler(minSizesim,prefSizesim,maxSizesim) );
               calcButton = new JButton("Calculation");
               simbox.add( calcButton );
               simbox.add(new Box.Filler(minSizesim,prefSizesim,maxSizesim) );
               simbox.add( Box.createVerticalStrut (10) );
               data_area = new JTextArea( data_area_string, 1, 50);
               data_area.setEditable( false );
               simbox2.add(data_area);
               simbox2.add( Box.createVerticalStrut (10) );
               // add simbox & simbox2 to panelB
               mSimPanel.add (simbox);
               mSimPanel.add (simbox2);
               this.getContentPane().add(mSimPanel, "2D Simulation");
               // register calcButton event handler
               calcButton.addActionListener(this);
               // register simstartButton & simresetButton
               simstartButton.addActionListener(this);
               simresetButton.addActionListener(this);
               // display results for panelA
               results();
               resultsArea.setText( results() );
               String work_string =
                    "The 2D Simulation is a work in progress so functionality is limited.\n"
                    + "It is best to verify the following results' values before beginning 2D Simulation: \n"
                    + "* Elapsed Time greater than 1 second\n"
                    + "* Distance greater than .001 miles\n"
                    + "Check back later for improvements in real time simulation.";
               JOptionPane.showMessageDialog( null, work_string);
          }//end try
          // process improperly formatted input
          catch ( NumberFormatException numberFormatException ) {
               JOptionPane.showMessageDialog( this,
               "You must enter numbers in decimal format or integers"     ,
               "Invalid Number Format" ,
               JOptionPane.ERROR_MESSAGE );
          } // end catch NumberFormatException
          catch ( ArithmeticException arithmeticException ) {
               JOptionPane.showMessageDialog( this,
               arithmeticException.toString(), "Arithmetic Exception" ,
               JOptionPane.ERROR_MESSAGE );
          } // end catch ArithmeticException
          catch ( Tare tare ) {
               JOptionPane.showMessageDialog( this,
               tare.toString(), "-90 <= range <= 90 " ,
               JOptionPane.ERROR_MESSAGE );
          } // end catch Tare
          catch ( Nve nve ) {
               JOptionPane.showMessageDialog( this,
               nve.toString(), " value less than zero" ,
               JOptionPane.ERROR_MESSAGE );
          } // end catch Nve
          catch ( Are are ) {
               JOptionPane.showMessageDialog( this,
               are.toString(), " value greater than maximum" ,
               JOptionPane.ERROR_MESSAGE );                    
          } // end catch Are
     }  // end method strtb
     public void reset()
          span_string = "";
          chord_string = "";
          thickness_string = "";
          mass_string = "";
          altitude_string = "";
          altitude_end_string = "";
          velocity_string = "";
          trajectory_angle_string = "";
          time_increment_string = "";
          rotation_factor_string = "";
          results_string = "";
          spanField.setText( span_string );
          chordField.setText( chord_string );
          thicknessField.setText( thickness_string );
          massField.setText( mass_string );
          altitudeField.setText( altitude_string );
          altitude_endField.setText( altitude_end_string );
          velocityField.setText( velocity_string );
          trajectory_angleField.setText( trajectory_angle_string );
          time_incrementField.setText( time_increment_string );
          rotation_factorField.setText( rotation_factor_string );
          resultsArea.setEditable( true );
          resultsArea.setText( results_string );
          resultsArea.setEditable( false );
          span = 0;
          chord = 0;
          thickness = 0;
          mass = 0;
          altitude = 0;
          altitude_end = 0;
          velocity = 0;
          trajectory_angle = 0;
          time_increment = 0;
          rotation_factor = 0;
          distance = 0;
          velocity_fps = 0;
          elapsed_time = 0;
          value = true;
          temp_Rank = 0;
          viscosity = 0;     
          density = 0;
          status_2 = true;
          orbit = 0;
          orbit_dbl = 0.0;
          new_distance = 0.0;
          c_miles = 0.0;
          d_min = 0.0;
          min = 0;
          sec = 0.0;
          Joules = 0.0;
          Tons_of_TNT= 0.0;
          Pounds_of_TNT= 0.0;           
          KiloTons_of_TNT= 0.0;
          Hiroshima_Bomb= 0.0;
          angleB = 0;
          max_dis = 0;
          max_screen_altitude_scale = 0;
          max_screen_distance_scale = 0;
          mCurrentPoint = 0;
          time_counter = 0;
          m = 0;
          n= 0;
          for( m = 0; m < MAX_TIME; m++ )
               for( n = 0; n < 6; n++ )
                    Results_Array[m][n] = 0;
     }   // end method reset
     public void calculate()
          double     s_x,                         //     distance in x direction
               s_y,                         //     distance in y direction
               s_x_old,                    //     distance in x direction(old)
               g_accel,                    //     local acceleration due to gravity     
               press,                         //     air pressure          
               x_velocity,                    //     velocity in x direction
               y_velocity,                    //     velocity in y direction
               ratio_R,                    //     term variable gravity               
               rot_time,                    //     time to next rotation
               temp_dim_1,                    //     swap variable rotation
               temp_dim_2,                    //     swap variable rotation
               temp_dim_3,                    //     swap variable
               c,                         //       local speed of sound
               Reynolds,                    //     Reynolds Number
               Reynolds_old,                    //     Reynolds Number(old)
               force_drag,                    //     drag force
               force_drag_x,                    //      drag force in x direction
               force_drag_y,                    //       drag force in y direction
               area_normal_to_flow,               //     area_normal_to_flow
               characteristic_dimension,          //     characteristic_dimension
               Cd,                         //     drag coefficient               
               M;                         //     Mach Number
          int count;                         //       counter
          int prior_time;                     //     time_counter - 1
          char test;                         //     character test condition
          boolean set_velocity;                    //     velocity set condition
          boolean change;                         //     rotation change condition
          boolean status_1;                    //     short cut condition     
          boolean status_3;                    //     short cut condition
          String short_cut;                    //     short cut message
          String input;                         //     short cut input
          String altitude_end_error_string;          
          // initialize applicable variables
          s_x = 0;
          s_x_old = 0;
          press = 0;
          x_velocity = 0;
          y_velocity = 0;     
          c = 0;     
          M = 0;
          Reynolds_old = 1;
          Reynolds = 1;
          ratio_R = 1;
          force_drag = 0;
          force_drag_x = 0.0;
          force_drag_y = 0.0;
          change = true;
          set_velocity = true;
          status_1 = true;
          status_3 = true;
          s_y = altitude;
          test = 'Y';
          rot_time = elapsed_time + time_increment * rotation_factor;
          short_cut = "";
          input = "";
          altitude_end_error_string =
               "Results have a probable error.\n"
               + "The end altitude value could be too high.\n"
               + "Reset and try some other values for inputs.";
          count = 0;
          temp_dim_1 = span;
          temp_dim_2 = chord;
          temp_dim_3 = thickness;
          if( altitude < altitude_end && trajectory_angle > 0 )
               status_2 = false;
          while(s_y > 0.0 && status_2 && sentinel)     
               // calculate local acceleration due to gravity
               ratio_R = R /( R + s_y );
               g_accel = G_SL * Math.pow( ratio_R, 2);
               // calculate air conditions
               Calc_Air( s_y );
               // kinematic reference:
               // x direction means a direction perpendicular to the
               // acceleration due to gravity with progression toward
               // a position at a later time
               // y direction means a direction having the same direction as
               // acceleration due to gravity
               // calculate velocity_fps from initial velocity(Mach Number)
               // & Reynolds
               if( set_velocity)
                    c = 49.0 * Math.sqrt(temp_Rank);
                    velocity_fps = velocity * c * 5280/3600;
                    if( trajectory_angle < 0 )
                         velocity_fps = 0 - Math.abs(velocity_fps);
                    // set velocity precision
                    if( trajectory_angle < 0.0000000001 && trajectory_angle > -0.0000000009 )
                         x_velocity = Math.abs(velocity_fps);
                         y_velocity = 0.0;
                    else if( trajectory_angle >= 89.99000000 && trajectory_angle <= 90.0000000)
                         x_velocity = 0.0;
                         y_velocity = Math.abs(velocity_fps);
                    else if( trajectory_angle <= -89.99000000 && trajectory_angle >= -90.0000000)
                         x_velocity = 0.0;
                         y_velocity = 0 - Math.abs(velocity_fps);
                    else
                         if( trajectory_angle >= 0 )
                              x_velocity = Math.abs(velocity_fps) * Math.cos(Math.abs(trajectory_angle) * Math.PI / 180);
                              y_velocity = Math.abs(velocity_fps) * Math.sin(Math.abs(trajectory_angle) * Math.PI / 180);
                         else
                              x_velocity = Math.abs(velocity_fps) * Math.cos(Math.abs(trajectory_angle) * Math.PI / 180);
                              y_velocity = 0 - Math.abs(velocity_fps) * Math.sin(Math.abs(trajectory_angle) * Math.PI / 180);
                    // calculate Reynolds number
                    Reynolds = Math.abs( density * Math.abs(velocity_fps) * chord / viscosity );
                    set_velocity = false;
                    // add first results to applicable variables for plotting
                    if( elapsed_time == 0)
                         Results_Array[ time_counter ][ 0 ] = (double)time_counter;
                         Results_Array[ time_counter ][ 1 ] = altitude;
                         Results_Array[ time_counter ][ 2 ] = distance /5280;
                         Results_Array[ time_counter ][ 3 ] = velocity_fps;
                         Results_Array[ time_counter ][ 4 ] = trajectory_angle;
                         Results_Array[ time_counter ][ 5 ] = distance;
                         // determine initial maximum altitude for scale plot
                         if(time_counter == 0)
                              max_screen_altitude_scale = (int)Results_Array[ time_counter ][ 1 ];
                         // determine initial maximum distance for scale plot
                         if(time_counter == 0)
                              if(scale_type)
                                   max_screen_distance_scale = (int)Res