Introduction to UML

Introduction to UML:

“UML (Unified Modeling Language) is a language used for visualizing, specifying, constructing and documenting the artifacts of a software intensive system.”

    Building Blocks of UML:

                                

v  Things

v  Relationships

v  Diagrams

    

   Things in UML:

Ø  Structural things

·         Classes

·         Interfaces

·         Collaborations

·         Use Cases

·         Active Classes

·         Components

·         Node

Ø  Behavioral things

·         Interactions

·         State machines

Ø  Grouping things

·         Packages

Ø  Annotational things

·         Notes

  Relationships in UML:

ü  Dependency

ü  Association

ü  Generalization

ü  Realization

 Diagrams in UML :

ü  Class Diagram

ü  Object Diagram

ü  Use case Diagram

ü  Sequence Diagram

ü  Collaboration Diagram

ü  State chart Diagram

ü  Activity Diagram

ü  Component Diagram

ü  Deployment Diagram

Use Case Diagrams:

           A use case diagram is a diagram that shows a set of use cases and actors and their relationships.

      A use case diagram commonly contain

·                     Use cases

·                     Actors

·                     Dependency

·                     Generalization and Association Relationships.

     Use case diagrams may also contain packages, which are used to group elements of your model into larger chants.

Use case diagram is used in one of two ways

1) To model the context of a system.

2) To model the requirements of a system.

Modeling Techniques:

                1. Identity the actors that surround the system by considering which groups require help from the system to perform their tasks, which groups are needed to execute the systems functions; which groups interact with external hardware or other software systems; and which groups perform secondary functions for administration & maintenance.

              2.Organize actors that are similar to one another in a generalization/specification hierarchy.

  3. Where it aids understandability, provide a stereotype for each such actor.

              4. Populate a use case diagram with these actors and specify the paths of communications from each actor to the system’s use cases.