第03讲-面向对象设计原则_设计实验

设计实验

有 3 个开关：a
b c

有 3 个电灯：x y z

要求实现：

a 能控制 x

b 能控制 x, y

c 能 x

注意：1个灯泡可以被多个开关控制；1个开关可以同时控制多个灯泡

所谓“控制”：当开关操作时，当前灯泡的状态发生翻转。亮->灭 或 灭->亮

import java.util.*;

class Light

{

private boolean state; // 灯的状态。true: 亮

public String toString()

{

if(state)

return "亮";

else

return "灭";

}

// 翻转状态

public void change()

{

state = !state;

}

}

class Switch

{

//Light[] a = ...

Vector v = new Vector();

public void addLight(Light x)

{

v.add(x);

}

// 按了一下开关

public void press()

{

for(int i=0; i<v.size(); i++)

{

Light p = (Light)v.get(i);

p.change(); // 反转电灯的当前状态

}

}

}

public class MyTest

{

private static void show_light(Light x, Light y, Light z)

{

System.out.println(x + "," + y + "," + z);

System.out.println("-----------------------");

}

public static void main(String[] args)

{

Light x = new Light();

Light y = new Light();

Light z = new Light();

Switch a = new Switch();

Switch b = new Switch();

Switch c = new Switch();

a.addLight(x);

b.addLight(x);

b.addLight(y);

c.addLight(x);

show_light(x, y, z);

a.press();

show_light(x, y, z);

b.press();

show_light(x, y, z);

c.press();

show_light(x, y, z);

}

}