5.抽象工厂模式-单例模式答案

(4) 抽象工厂模式
电脑配件生产工厂生产内存、CPU等硬件设备，这些内存、CPU的品牌、型号并不一定相同，根据下面的“产品等级结构-产品族”示意图，使用抽象工厂模式实现电脑配件生产过程并绘制相应的类图，绘制类图并编程实现。

interface CPU
{
void discribe();
}
interface RAM
{
void discribe();
}
class PcCPU implements CPU
{
public void discribe()
{
System.out.println("PcCPU");
}
}
class MacCPU implements CPU
{
public void discribe()
{
System.out.println("MacCPU");
}
}
class PcRAM implements RAM
{
public void discribe()
{
System.out.println("PcRAM");
}
}
class MacRAM implements RAM
{
public void discribe()
{
System.out.println("MacRAM");
}
}
interface ComputerPartsFactory
{
CPU produceCPU();
RAM produceRAM();
}
class PcFactory implements ComputerPartsFactory
{
public PcCPU produceCPU() {
System.out.println("PcCPU produced!");
return new PcCPU();
}
public PcRAM produceRAM() {
System.out.println("PcRAM produced!");
return new PcRAM();
}
}
class MacFactory implements ComputerPartsFactory
{
public MacCPU produceCPU() {
System.out.println("MacCPU produced!");
return new MacCPU();
}
public MacRAM produceRAM() {
System.out.println("MacRAM produced!");
return new MacRAM();
}
}
class ComputerPartsClient
{
public static void main(String a[])
{
ComputerPartsFactory factory;
CPU cpu;
RAM ram;
factory=(ComputerPartsFactory)XMLUtil.getBean();//Pc OR Mac
cpu=factory.produceCPU();
cpu.discribe();
ram=factory.produceRAM();
ram.discribe();
}
}
(6) 单例模式
用懒汉式单例实现在某系统运行时，其登录界面类LoginForm只能够弹出一个，如果第二次实例化该类则提示“程序已运行”。

绘制类图并编程实现。

class LoginForm extends JFrame{ //Java.swing包中的JFrame类用于创建窗口
private static LoginForm uniqueInstance=null;
private LoginForm()
{
//设置标题
this.setTitle("LoginForm");
this.setSize(400, 300); //setSize(int width, int height)
//设置关闭按钮的事件
this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//设置是否可见
this.setVisible(true);
}
public static LoginForm getInstance()
{
if(uniqueInstance==null)
{
uniqueInstance=new LoginForm();
}else{
JOptionPane.showMessageDialog(null, "LoginFrame已经在运行！");
}
return uniqueInstance;
}
}
class LoginFormClient
{
public static void main(String a[])
{
LoginForm s1=null,s2=null;
s1=LoginForm.getInstance();
s2=LoginForm.getInstance();
System.out.println("s1==s2?");
System.out.println(s1==s2);
}
}
运行结果：。