public class SubSystemA {
    public void subSystem() {
        System.out.println("subSystem A");
    }
}

public class SubSystemB {
    public void subSystem() {
        System.out.println("subSystem B");
    }
}

public class Facade {
    private SubSystemA a = new SubSystemA();
    private SubSystemB b = new SubSystemB();
    /**
     * 提供對外接口
     */
    public void subSystemA() {
        this.a.subSystem();
    }
    /**
     * 提供對外接口
     */
    public void subSystemB() {
        this.b.subSystem();
    }
}

    public static void main(String[] args) {
        Facade facade = new Facade();
        facade.subSystemA();
        facade.subSystemB();
    }

public class StockSys {
    /**
     * 庫存校驗
     */
    public Boolean verify(){
        if (Math.random()*10 >5) {
            System.out.println("StockSys verify success");
            return true;
        }
        System.out.println("StockSys verify fail");
        return  false;
    }
}

public class PaySys {
    /**
     * 支付
     */
    public Boolean pay() {
        if (Math.random()*10 >2) {
            System.out.println("PaySys pay success");
            return true;
        }
        System.out.println("PaySys pay fail");
        return  false;
    }
}

public class LogisticsSys {
    /**
     * 發(fā)貨
     */
    public void ship() {
        System.out.println("logistics ship");
    }
}

public class MySys {
    StockSys stockSys = new StockSys();
    PaySys paySys = new PaySys();
    LogisticsSys logisticsSys = new LogisticsSys();
    public void order() {
        if (stockSys.verify()) {
            if (paySys.pay()) {
                logisticsSys.ship();
            }
        }
    }
}

    public static void main(String[] args) {
        new MySys().order();
    }