外观模式

interface Chip {
    public void startUp();
    public void shutDown();
}

/*构建电脑子系统，包含CPU，Memory，Flash等*/
class CPU implements Chip {
    public void startUp() {
        System.out.println("CPU startUp");
    }
    public void shutDown() {
        System.out.println("CPU shutDown");
    }
}

class Memory implements Chip {
    public void startUp() {
        System.out.println("Memory startUp");
    }
    public void shutDown() {
        System.out.println("Memory shutDown");
    }
}

class Flash implements Chip {
    public void startUp() {
        System.out.println("Falsh startUp");
    }
    public void shutDown() {
        System.out.println("Falsh shutDown");
    }
}

/*提供一个门面类，外界通过它提供的函数来开关电脑内部的各个器件*/
class ComputerSystem {
    private Chip cpu, memory, flash;
    public ComputerSystem() {
        cpu = new CPU();
        memory = new Memory();
        flash = new Flash();        
    }

    void startUp() {
        cpu.startUp();
        memory.startUp();
        flash.startUp();
    }

    void shutDown() {
        cpu.shutDown();
        memory.shutDown();
        flash.shutDown();
    }

    void startUpFlash() {
        flash.startUp();
    }

    void shutDownFlash() {
        flash.shutDown();
    }
}

public class FacadePattern {
    public static void main(String args[]) {
        ComputerSystem s = new ComputerSystem(); /*这里避免了对电脑的每一个器件的直接操作*/

        s.startUp();

        s.shutDown();
    }
}