Monday, 5 March 2012

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.


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.
      objects are the instance of class.

       it represents the association between the objects

Component Diagram

•It is used to describe the dependency  between various software components.
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.
Components->represents the software entity.

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


 Association->represents the communication between hardware components 


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.

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

Actor->communicate with the object


Administrator use a web application to manage user account

Find User
Update User


It is  independent of particular programming languages.
•It encourage the growth of the OO tools market.