UML diagram related knowledge

UML Graph related knowledge

Detailed explanation UML Graph like graph

The basic expression of class

Each rectangle represents a class （ General class diagrams are divided into 3 Classes , Some class diagrams are divided into 5 Classes ）

• The first part is the class name
  • Normal writing instructions are ordinary classes that can be instantiated
  • The class name is written in italics, indicating that it is an abstract class
  • If the class name is underlined, it indicates that it is a static class
• The second part is the properties of the class
  • Format ： Property name ： Attribute types
  • + Description attribute is public
  • # Description attribute is protected
  • - Description attribute is private
• The third part is the method of class
  • Format ： Method name ： Method return value type
  • + The description method is public
  • # The description method is protected
  • - The description method is private
  • If there is an underscore under the method name, it indicates that it is a static method

The expression of the relationship between classes

Inherit ： From child to parent

Realization ： The implementation class points to the interface

rely on ： From the user to the user

If A Point to B, shows A Used in B, Usage includes A There are B Class instantiates the of the object local variable .A There are methods in the class to B As an instantiated class Parameters ,A A method in the class called B Class Static methods

relation ： From the owner to the owner

If A Point to B, shows A There are B Class Member variables

Teachers and students

polymerization ： From the whole to the part

If A Point to B, shows A There are B Class Member variables , But unlike relevance ,A Classes and B Classes have logical relationships .A A class is a whole ,B Class is part of .A Class by B Class a , meanwhile B Class, even if it's not there A Classes can also exist alone

Combine ： From the whole to the part

If A Point to B, shows A There are B Class Member variables , But unlike relevance ,A Classes and B Classes have logical relationships .A A class is a whole ,B Class is part of .A Class by B Class a . But unlike aggregation , If B Class is not in A Class cannot exist alone

Interface

An interface is a special class , Has the structure of a class but cannot be instantiated , Can only be realized （ Inherit ）

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Interface

An interface is a special class , Has the structure of a class but cannot be instantiated , Can only be realized （ Inherit ）