UML Tutorial

Introducing the UML

•The Unified Modeling Language or UML is a standard  language for specifying, visualizing, constructing, and documenting the  software systems.

•The UML uses mostly graphical notations to express the design of software projects.

•UML describes a notation and not a process. 

•UML model describes what a system is supposed to do. It does not tell how to implement the system.

Uml diagrams

•In  UML certain number of graphical elements combined into diagrams.

•Because it is a language, the UML has rules for combining these elements.

•Uml consists of eight basic diagram 

1.      Class Diagram
2.      Object Diagram
3.      Component Diagram
4.      Deployment Diagram
5.      Use Case Diagram
6.      Collaboration Diagram
7.      Activity Diagram
8.      State Diagram

Class Diagram
•It is used to describe the structure of a class including the properties and methods and the relationship between the classes.

         
Notations

 class

Relationship between classes

Aggregation ->line with a hollow diamond

Composition ->line with a filled diamond

Generalization-> line with a hollow arrow head

realization->dashed line with a hollow arrow head

Association->line connecting two classes

Object diagram

•It is used to describe the system at a particular point of time.

     

 Notations

 Objects

      objects are the instance of class.

Association

       it represents the association between the objects

Component Diagram

•It is used to describe the dependency  between various software components.

     
  Notations

Component  ->represents a software entity in a system.

 

Dependency ->represents the relationship between the components.

 

 

Deployment Diagram

•It is used to represent the hardware used to implement the system and  association between hardware components.

Notation

Components->represents the software entity.

Node ->represents a piece of hardware in a system.

  

  





 Association->represents the communication between hardware components 

example

Use case diagram

•It identifies the functionality provided by the system (use case) ,the users that interact with the system (Actor) and the association between the user and functionality.

Notations

        use case->functionality provided by the system

Actor-> user or another system that interact with the use case

Association -> link actors with the use case
 

example shows a user placing an order with a sales company might follow these steps.

 

State Diagram

It represents the various state an object can go through and event that cause the state transition.

      Notations

     state ->

Transition-> represent the  changing object state caused by events

Initial State -> state of an object before transition 

Final State ->represent the destruction of an object.

State diagram of a light

Activity Diagram

•It is used to represent the work flow with in a system.

•It shows steps (activities) ,decision point and branch

Notations

–Activity->each step in a work flow

 

–Initial state->entry point

  

–Final state->end of work flow

 

–Transition ->

 

–Decision ->represent a condition

Activity diagram to find the factorial of a number

Collaboration Diagram

•It represent the interaction between the objects.

Notations

 Object->

 Message->tells the receiving object to execute one of its operation

Actor->communicate with the object

example:

Administrator use a web application to manage user account

 

Find User
   LookUpUser
Update User
   ValidateUser
   UpdateUser

 

Conclusion

•It is  independent of particular programming languages.

•It encourage the growth of the OO tools market.