Identifying Domain Classes in OOP

Identifying Domain Classes from Problem Statements

• Identifying domain classes is crucial in object-oriented programming, as classes represent the structural units of a system.
• Understanding the classes beforehand is vital in implementing system logic.
• The lecture focuses on identifying classes from a given problem statement.

Objectives

• Learners will understand the concept of domain classes.
• Learners will identify potential domain classes from a given problem statement.

Domain Class

• In object-oriented models, domain object models are significant for effectively understanding and addressing problems.
• Domain models serve as conceptual models for proper problem insight.
• Core components are domain classes.
• Domain classes abstract key entities, concepts, or ideas in problem statements.
• These classes represent business activities in the analysis phase.

Traditional Techniques for Identifying Classes

1. Grammatical Approach Using Nouns

• This approach, popularized by Russell J. Abbot and Grady Booch, uses grammatical analysis of the problem statement to identify potential classes.
• Steps involve:
  • Obtaining a descriptive English problem statement (use case diagram).
  • Identifying nouns, pronouns, and noun phrases.
  • Listing potential classes based on noun categories (e.g., people, places, things, organizations, concepts, events).

Advantages

• Easy to understand and apply.
• Doesn't necessitate the problem statement to be in English.

Disadvantages

• Problem statements might not always lead to accurate class identification.
• Redundant classes or classes representing aggregates of other classes might be identified.

2. Using Generalization

• Classes are derived based on common behaviors of objects.

3. Using Subclasses

• Identifying classes based on similar characteristics.
• Creates specialized classes that contribute to generalized classes.

Steps to Identify Domain Classes from a Problem Statement

• Create a list of potential classes by identifying nouns and noun phrases in the narrative problem statement.
• Experts or domain knowledge can be used to identify additional classes.
• Eliminate redundant or irrelevant classes.
• Classify potential objects based on predefined categories.

Categories for Potential Domain Classes

• People: Individuals performing functions.

• Places: Areas specific for people or things.

• Things: Physical objects.

• Organizations: Collections with defined missions.

• Concepts: Ideas or principles.

• Events: Occurrences at specific times/steps in an ordered sequence.

• Repeated or similar nouns or noun phrases may represent the same thing or different things depending on context.

• Finalize top-level classes by giving names to identified object groups and refine the list.

Advanced Concepts

• Defining domain classes may require specialized knowledge.
• Identification relies on domain expertise for effective class definition from English text.

This quiz focuses on identifying domain classes from problem statements, a vital skill in object-oriented programming. Learners will explore traditional techniques, including the grammatical approach using nouns, to discern key entities essential for system design. Gain a solid foundation in building effective domain models for your programming projects.