Difference between revisions of "Class Diagram"

Latest revision as of 18:57, 16 February 2022

Definition

A Class Diagram is a graphical UML diagram that is a type of static structure diagram. It describes a system by showing the system's classes, their attributes, operations (or methods), and the relationships among objects. A class is the blueprint for a set of similar objects that appear in the system to be specified. Class attributes allow to store information that has generally different specific values for each instance (object) of the class. Operations specify how specific behavior can be triggered on individual objects.

The concepts behind a class diagram originate from conceptual data modeling and object-oriented software development. The class diagram is based primarily on the concepts of class, generalization, and association. The documented elements and the relationships between them do not change over time.

The class diagram is the main building block of object-oriented modeling. It is used for general conceptual modeling of the structure of the application, and for detailed modeling, translating the models into programming code. Class diagrams can also be used for data modeling. The classes in a class diagram represent both the main elements, interactions in the application, and the classes to be programmed.

A class diagram is distinct but related to the Object Diagram

PlantUML Elements

A PlantUML class diagram specifies and shows the following:

A Class
Class Attributes
Class Methods

Example

@startuml
skinparam handwritten true

abstract class Borrower {
  -name : String
}

class CorporateBorrower extends Borrower {
 -market_capitalisation : number
}

class PrivateBorrower extends Borrower {
 -annual_income : number
}

@enduml

References

@@ Line 1: / Line 1: @@
 == Definition ==
-A '''Class Diagram''' is a graphical UML diagram  is a type of static structure diagram that describes the a system by showing the system's classes, their attributes, operations (or methods), and the relationships among objects.
+A '''Class Diagram''' is a graphical UML diagram  that is a type of static structure diagram. It describes a system by showing the system's classes, their attributes, operations (or methods), and the relationships among objects. A class is the blueprint for a set of similar objects that appear
+in the system to be specified. Class attributes allow to store information that has generally different specific values for each instance (object) of the class. Operations specify how specific behavior can be triggered on individual objects.
+The concepts behind a class diagram originate from conceptual data modeling and object-oriented software development. The class diagram is based primarily on the concepts of class, generalization, and association. The documented elements and the relationships between them do not change over time.
 The class diagram is the main building block of object-oriented modeling. It is used for general conceptual modeling of the structure of the application, and for detailed modeling, translating the models into programming code. Class diagrams can also be used for data modeling. The classes in a class diagram represent both the main elements, interactions in the application, and the classes to be programmed.
+A class diagram is distinct but related to the [[Object Diagram]]
 == PlantUML Elements ==
-A [[PlantUML]] use case diagram specifies and shows the following:
+A [[PlantUML]] class diagram specifies and shows the following:
-* An Actor represents a requirement (stimulus) of the system
-* An Action representing a capability of the system
-* A Subject representing the item acted upon by an Action of the system
-The use cases are typically represented by either circles or ellipses. The actors are often shown as stick figures.
+* A Class
+* Class Attributes
+* Class Methods
 == Example ==
@@ Line 18: / Line 20: @@
 <pre>
 @startuml
-skinparam actorStyle Hollow
-left to right direction
 skinparam handwritten true
-skinparam packageStyle rectangle
-actor Customer
+abstract class Borrower {
+  -name : String
+}
-actor Clerk
+class CorporateBorrower extends Borrower {
-:Bank Clerk: as Clerk
+ -market_capitalisation : number
+}
-rectangle Deposit {
+class PrivateBorrower extends Borrower {
-Customer -- (Help)
+ -annual_income : number
-(Help) .> (Identification) : optionally
-(Identification) .> (Payment) : leads
-(Payment) .> (Receipt) : finally
-(Help) -- Clerk
 }
 @enduml
 </pre>
-[[File:Usecase.png|Use Case Diagram]]
+[[File:Class.png|Class Diagram]]
 == References ==
 <references/>
-* [[wikipedia:Use case diagram | Use Case Diagram @ Wikipedia]]
+* [[wikipedia:Class diagram | Class Diagram @ Wikipedia]]
 * [https://plantuml.com/guide PlantUML Language Reference Guide]
 [[Category:PlantUML]]