第十三讲：外观模式

Facade把子系统的功能都包含进来了,这些子系统都有一个doSomething(),来给Client1和Client2调用的.

缺点是客户端是直接调用这些功能模块的.

---

//外观
//最大的一个好处是我们的老百姓MainClass不用再调用子系统,因为你调用子系统的话还需要判断要调用哪些子系统,
// 
public class Facade {
     private  SystemA systemA;
     private  SystemB systemB;
     private  SystemC systemC;
    public Facade() {
        //super();
        systemA = new SystemA();
        systemB = new SystemB();
        systemC = new SystemC();    
    }
   
     //public void doSomething(){
    public void doABC(){
         
         this.systemA.doSomething();
         this.systemB.doSomething();
         this.systemC.doSomething();
         
     }
     
     public void doAB(){
         this.systemA.doSomething();
         this.systemB.doSomething();
         
     }
     
}

//客户端...
//缺点是客户端是直接调用这些功能模块的.
//外观模式将客户端与具体的功能模块相区分,客户端所要知道的只有这个外观了.以后会接触门面模式,与外观模式是
//完全不同的概念.
//客户端只调用外观的方法,至于外观的方法里面怎么将功能模块组合和调用我不管.
public class MainClass {
  /*   public static void main(String[] args) {
        //实现A子系统功能
        SystemA  systemA = new SystemA();
        systemA.doSomething();
        
        SystemB systemB = new SystemB();
        systemB.doSomething();
        
        SystemC systemC  =   new SystemC();
        systemC.doSomething();
        
    } */
    public static void main(String[] args) {
        Facade  facade = new Facade();//这样客户端不与子系统打交道了,只与外观Facade打交道了.
        //facade.doSomething();
        facade.doABC();
    }

}

public class MainClass2 {
    public static void main(String[] args) {
/*        //实现A子系统功能
        SystemA systemA  = new SystemA();
        systemA.doSomething();
        
        SystemB systemB = new SystemB();
        systemB.doSomething();*/
        
        Facade facade  =  new Facade();
        facade.doAB();
    }
}

/**
 * A子系统
 * @author zhongzh
 *
 */
public class SystemA {
     public void doSomething(){
         System.out.println("实现A子系统功能");
         
     }
}

/**
 * B子系统
 * @author zhongzh
 *
 */
public class SystemB {
     /*
      * B子系统实现
      * 
      */
    
    public void doSomething(){
        System.out.println("实现B子系统功能");
    }
}

/**
 * C子系统
 * @author zhongzh
 *
 */
public class SystemC {
     /*
      * C子系统实现功能
      * 
      */
    
    public void doSomething(){
        System.out.println("实现C子系统功能");
    }
}

---

package com.ibeifeng.news;

public class GuoZai {
    public void mai(){
        System.out.println("买国债");
        
        
    }
}

package com.ibeifeng.news;

public class Gupiao {
   public  void mai(){
       System.out.println("买股票");
   }
}

package com.ibeifeng.news;
//基金有很多种,有货币型的基金,
//外观模式include创建一个引用.
public class JiJin {
     private  Gupiao  gupiao;
     private  GuoZai  guozai;
     private  Qihuo qihuo;
    public JiJin() {
        this.guozai = new GuoZai();
        this.gupiao = new Gupiao();
        this.qihuo  = new Qihuo();
        
    }
    public void maiJijinA(){
        this.guozai.mai();
        this.gupiao.mai();
        
    }
    public void maiJijinB(){
        this.guozai.mai();
        this.gupiao.mai();
        this.qihuo.chao();
    }
     
}

package com.ibeifeng.news;

public class MainClass {
    public static void main(String[] args) {
/*        //80年代,基金出现之前
        Gupiao  gupiao  = new Gupiao();
        gupiao.mai();
        
        Qihuo qihuo = new Qihuo();
        qihuo.chao();
        
        GuoZai guozhai =  new GuoZai();
        guozhai.mai();*/
        
        //有了基金之后
        /*JiJin jijin =  new JiJin();
        jijin.maiJijinA();*/
        
        JiJin jijin =  new JiJin();//另外一个老百姓...
        jijin.maiJijinB();
        
    }
}

package com.ibeifeng.news;

public class Qihuo {
       public void  chao(){
            
            System.out.println("买期货");
        }
}