Observer

 

 1 Class secretary
 2 {
 3 Name;
 4 Event OnBossCome;
 5  BossCome()
 6 {
 7  
 8 } 
 9 }
10  
11 //Book
12  Ilist<StockObserver> observers
13 Attach
14 Notify()
15 {
16 }
17 Action
18