Chapter 5 - Domain Modeling Part 1

Chapter 5: Domain Modeling Part 1 – UML Class Diagram

Key Takeaway Points

• Domain modeling aids in understanding the application domain.

• Five Steps of Domain Modeling:

  • Collect information about the application domain.

  • Brainstorm ideas.

  • Classify brainstorming results.

  • Visualize using UML class diagrams.

  • Perform inspections and reviews.

Acquiring Requirements

• Domain modeling contextualizes software architecture leading to use case derivation and allocation to iterations.

• Involves understanding business goals, current situations, and preliminary requirements.

What Is a Model?

• Conceptual representation of a system, useful for studying its properties.

Need for Models

• Collective understanding among diverse team members.

• Facilitates communication of perceptions and design ideas.

• Essential during the maintenance phase for enhancements.

Domain Modeling

• What: Process for understanding the application domain.

• Why: Necessary due to varying backgrounds of software engineers impacting their understanding.

• How: Collect information, brainstorming, classification, visualize via UML.

Domain Model

• Defines application domain concepts via classes, attributes, and relationships.

• Enhances understanding and communication among team members and stakeholders.

• Acts as a basis for design, implementation, and maintenance.

Object-Oriented Paradigm

• Views the real world as consisting of interacting objects.

Important Object-Oriented Concepts

• Class: Abstraction of objects with similar properties and behaviors.

• Attribute: Defines class properties.

• Operation: Defines class behaviors.

• Encapsulation: Instance of a class combining properties and behavior.

• Information Hiding: Reducing the impact of changes on other program parts.

• Polymorphism: One form taking multiple implementations.

UML Class Diagram

• Structural representation of classes and their relationships, attributes, and operations.

• Domain models are class diagrams excluding operations.

Inheritance Relationship

• Generalization/specialization relationship illustrated as IS-A relation.

• Example: A car is a vehicle (generalization of vehicle).

Object and Attribute Distinction

• Objects exist independently; attributes require objects for context.

• Attributes describe objects and store state without independent existence.

Inheritance Tests

• IS-A Test: Each subclass instance is also an instance of the superclass.

• Conformance Test: Superclass relationships apply to subclasses.

Aggregation Relationship

• Represents part-of relationships between objects.

• Example: Engine is part of a car.

Association Relationship

• General relationships available in application.

• Example: Instructor teaches a course.

Role and Multiplicity

• Illustrates either role played by objects or the quantity involved in associations.

Summary: Relationships in UML Class Diagrams

• Inheritance: IS-A relationship.

• Aggregation: Part-of relationship.

• Association: General relationships, direction indicated by arrows.

Sample Domain Model

• Illustrates user attributes and admin management roles in a modeled system.

Applying Agile Principles

• Collaborate with users for application understanding.

• Simplify and expand domain models as necessary.