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1 import java.awt.*;
2 import java.awt.event.*;
3 import JSci.physics.*;
4
5
10 public final class Collision extends Frame {
11 private ClassicalParticle2D A=new ClassicalParticle2D();
12 private ClassicalParticle2D B=new ClassicalParticle2D();
13 private TextField massA=new TextField("2.0");
14 private TextField massB=new TextField("2.0");
15 private TextField velXA=new TextField("3.0");
16 private TextField velXB=new TextField("3.0");
17 private TextField velYA=new TextField("3.0");
18 private TextField velYB=new TextField("-1.0");
19 private VectorDisplay display=new VectorDisplay(4);
20 private Label energyBefore=new Label();
21 private Label energyAfter=new Label();
22 private Label momentumXBefore=new Label();
23 private Label momentumXAfter=new Label();
24 private Label momentumYBefore=new Label();
25 private Label momentumYAfter=new Label();
26 public static void main(String  arg[]) {
27 Frame app=new Collision();
28 app.setSize(500,500);
29 app.setVisible(true);
30 }
31 public Collision() {
32 super("Collision!");
33 final Panel controls=new Panel();
34 controls.setLayout(new GridLayout(4,3));
35 final Button button=new Button("Collide");
36 button.addActionListener(new ActionListener() {
37 public void actionPerformed(ActionEvent evt) {
38 collide();
39 }
40 });
41 controls.add(button);
42 final Label labelA=new Label("Particle A");
43 labelA.setForeground(Color.red);
44 controls.add(labelA);
45 final Label labelB=new Label("Particle B");
46 labelB.setForeground(Color.blue);
47 controls.add(labelB);
48 controls.add(new Label("Mass:"));
49 controls.add(massA);
50 controls.add(massB);
51 controls.add(new Label("X Velocity:"));
52 controls.add(velXA);
53 controls.add(velXB);
54 controls.add(new Label("Y Velocity:"));
55 controls.add(velYA);
56 controls.add(velYB);
57 final Panel info=new Panel();
58 info.setLayout(new GridLayout(4,3));
59 info.add(new Panel());
60 info.add(new Label("Before"));
61 info.add(new Label("After"));
62 info.add(new Label("Energy:"));
63 info.add(energyBefore);
64 info.add(energyAfter);
65 info.add(new Label("X Momentum:"));
66 info.add(momentumXBefore);
67 info.add(momentumXAfter);
68 info.add(new Label("Y Momentum:"));
69 info.add(momentumYBefore);
70 info.add(momentumYAfter);
71 add(controls,"North");
72 add(display,"Center");
73 add(info,"South");
74 addWindowListener(new WindowAdapter() {
75 public void windowClosing(WindowEvent evt) {
76 dispose();
77 System.exit(0);
78 }
79 });
80 collide();
81 }
82 private void collide() {
83 A.setMass(parseDouble(massA.getText()));
84 A.setVelocity(parseDouble(velXA.getText()),parseDouble(velYA.getText()));
85 B.setMass(parseDouble(massB.getText()));
86 B.setVelocity(parseDouble(velXB.getText()),parseDouble(velYB.getText()));
87 display.setVector(0,-A.getXVelocity(),A.getYVelocity());
88 display.setVector(1,-B.getXVelocity(),B.getYVelocity());
89 energyBefore.setText(Double.toString(A.energy()+B.energy()));
90 momentumXBefore.setText(Double.toString(A.getXMomentum()+B.getXMomentum()));
91 momentumYBefore.setText(Double.toString(A.getYMomentum()+B.getYMomentum()));
92 A.collide(B, 0.0);
93 display.setVector(2,A.getXVelocity(),-A.getYVelocity());
94 display.setVector(3,B.getXVelocity(),-B.getYVelocity());
95 energyAfter.setText(Double.toString(A.energy()+B.energy()));
96 momentumXAfter.setText(Double.toString(A.getXMomentum()+B.getXMomentum()));
97 momentumYAfter.setText(Double.toString(A.getYMomentum()+B.getYMomentum()));
98 }
99 private static double parseDouble(String s) {
100 return Double.valueOf(s).doubleValue();
101 }
102 private final class VectorDisplay extends Canvas {
103 private float vecX[],vecY[];
104 private Color color[];
105 public VectorDisplay(int n) {
106 vecX=new float[n];
107 vecY=new float[n];
108 color=new Color[n];
109 color[0]=Color.red;
110 color[1]=Color.blue;
111 color[2]=Color.red;
112 color[3]=Color.blue;
113 }
114 public void setVector(int i,double dx,double dy) {
115 final double norm=Math.sqrt(dx*dx+dy*dy);
116 vecX[i]=(float)(dx/norm);
117 vecY[i]=(float)(dy/norm);
118 repaint();
119 }
120 public void paint(Graphics g) {
121 final int ox=getSize().width/2;
122 final int oy=getSize().height/2;
123 int endX,endY;
124 for(int i=0;i<vecX.length;i++) {
125 endX=ox+(int)((ox-20)*vecX[i]);
126 endY=oy+(int)((oy-20)*vecY[i]);
127 g.setColor(color[i]);
128 g.drawLine(ox,oy,endX,endY);
129 }
130 }
131 public Dimension getPreferredSize() {
132 return new Dimension(100,100);
133 }
134 }
135 }
136
137
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Java API By Example, From Geeks To Geeks.