command模式

使用下面的代码调用：

   
   public static void main(String[] args){
       List worker = new ArrayList();
       worker.add(new Robber());
       worker.add(new Teacher());
       worker.add(new Student());
       Iterator it = worker.iterator();
       while(it.hasNext()){
           ((Work)it.next()).execute();
       }
   }