UML

1. Docs
• 标准建模语言UML教程
• UML Programming Guide 核心设计技术
• UML Distilled UML精髓
• The Unified Modeling Lanage Reference Manual
2. Relation
• Use-a
  
  A class C1 need to invoke methods of class C2, but C2 is not field of C1,it may be passed to some method(s) of C1 as argument, or it may be created temporarily in method(s) of C1.
• Has-a
  
  Class C1 has object(s) of class C2 as its field(s).
• Is-a
  
  Class C1 inheris class C2.
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