(Control a clock) Modify Listing 1, ClockPane.java, to add the animation into this class a...

(Control a clock) Modify Listing 1, ClockPane.java, to add the animation into this class and add two methods start() and stop() to start and stop the clock. Write a program that lets the user control the clock with the Start and Stop buttons, as shown in Figure 1a.

FIGURE 1 (a) Exercise allows the user to start and stop a clock. (b and c) The balls are dropped into the bean machine.

LISTING 1 ClockPane.java

1 import java.util.Calendar;
2 import java.util.GregorianCalendar;
3 import javafx.scene.layout.Pane;
4 import javafx.scene.paint.Color;
5 import javafx.scene.shape.Circle;
6 import javafx.scene.shape.Line;
7 import javafx.scene.text.Text;
8
9 public class ClockPane extends Pane {
10 private int hour;
11 private int minute;
12 private int second;
13
14 // Clock pane's width and height
15 private double w = 250, h = 250;
16
17 /** Construct a default clock with the current time*/
18 public ClockPane() {
19 setCurrentTime();
20 }
21
22 /** Construct a clock with specified hour, minute, and second */
23 public ClockPane(int hour, int minute, int second) {
24 this.hour = hour;
25 this.minute = minute;
26 this.second = second;
27 paintClock();
28 }
29
30 /** Return hour */
31 public int getHour() {
32 return hour;
33 }
34
35 /** Set a new hour */
36 public void setHour(int hour) {
37 this.hour = hour;
38 paintClock();
39 }
40
41 /** Return minute */
42 public int getMinute() {
43 return minute;
44 }
45
46 /** Set a new minute */
47 public void setMinute(int minute) {
48 this.minute = minute;
49 paintClock();
50 }
51
52 /** Return second */
53 public int getSecond() {
54 return second;
55 }
56
57 /** Set a new second */
58 public void setSecond(int second) {
59 this.second = second;
60 paintClock();
61 }
62
63 /** Return clock pane's width */
64 public double getW() {
65 return w;
66 }
67
68 /** Set clock pane's width */
69 public void setW(double w) {
70 this.w = w;
71 paintClock();
72 }
73
74 /** Return clock pane's height */
75 public double getH() {
76 return h;
77 }
78
79 /** Set clock pane's height */
80 public void setH(double h) {
81 this.h = h;
82 paintClock();
83 }
84
85 /* Set the current time for the clock */
86 public void setCurrentTime() {
87 // Construct a calendar for the current date and time
88 Calendar calendar = new GregorianCalendar();
89
90 // Set current hour, minute and second
91 this.hour = calendar.get(Calendar.HOUR_OF_DAY);
92 this.minute = calendar.get(Calendar.MINUTE);
93 this.second = calendar.get(Calendar.SECOND);
94
95 paintClock(); // Repaint the clock
96 }
97
98 /** Paint the clock */
99 protected void paintClock() {
100 // Initialize clock parameters
101 double clockRadius = Math.min(w, h) * 0.8 * 0.5;
102 double centerX = w / 2;
103 double centerY = h / 2;
104
105 // Draw circle
106 Circle circle = new Circle(centerX, centerY, clockRadius);
107 circle.setFill(Color.WHITE);
108 circle.setStroke(Color.BLACK);
109 Text t1 = new Text(centerX - 5, centerY - clockRadius + 12, "12");
110 Text t2 = new Text(centerX - clockRadius + 3, centerY + 5, "9");
111 Text t3 = new Text(centerX + clockRadius - 10, centerY + 3, "3");
112 Text t4 = new Text(centerX - 3, centerY + clockRadius - 3, "6");
113
114 // Draw second hand
115 double sLength = clockRadius * 0.8;
116 double secondX = centerX + sLength *
117 Math.sin(second * (2 * Math.PI / 60));
118 double secondY = centerY - sLength *
119 Math.cos(second * (2 * Math.PI / 60));
120 Line sLine = new Line(centerX, centerY, secondX, secondY);
121 sLine.setStroke(Color.RED);
122
123 // Draw minute hand
124 double mLength = clockRadius * 0.65;
125 double xMinute = centerX + mLength *
126 Math.sin(minute * (2 * Math.PI / 60));
127 double minuteY = centerY - mLength *
128 Math.cos(minute * (2 * Math.PI / 60));
129 Line mLine = new Line(centerX, centerY, xMinute, minuteY);
130 mLine.setStroke(Color.BLUE);
131
132 // Draw hour hand
133 double hLength = clockRadius * 0.5;
134 double hourX = centerX + hLength *
135 Math.sin((hour % 12 + minute / 60.0) * (2 * Math.PI / 12));
136 double hourY = centerY - hLength *
137 Math.cos((hour % 12 + minute / 60.0) * (2 * Math.PI / 12));
138 Line hLine = new Line(centerX, centerY, hourX, hourY);
139 hLine.setStroke(Color.GREEN);
140
141 getChildren().clear();
142 getChildren().addAll(circle, t1, t2, t3, t4, sLine, mLine, hLine);
143 }
144 }