Question

If the items on the following list appeared in a problem domain description, which would be potential classes? Animal Medication Nurse Inoculate Operate Advertise Doctor Invoice Measure Patient Client Customer

Short answer

Answer: The potential classes that can be formed from the given list of items are Animal, Medication, Nurse, Doctor, Patient, Client, and Customer. These items can be used as classes because they represent objects, roles, or categories and can be used for modeling within a problem domain. The other items (Inoculate, Operate, Advertise, Invoice, Measure) are not considered as potential classes because they represent actions or processes and are more suitable for implementing as methods within a class.

Step-by-step solution

Identify Potential Classes

From the list of items, carefully look for objects, roles, or categories that might be related to a problem domain. In our case, the following items can be considered as potential classes: 1. Animal 2. Medication 3. Nurse 4. Doctor 5. Patient 6. Client 7. Customer These potential classes can be used to create objects and define properties or methods relevant to a particular problem domain.

Explain Why Other Items are not Potential Classes

The remaining items in the list are considered as potential actions or processes, which can be implemented as methods within a class. These items are: 1. Inoculate 2. Operate 3. Advertise 4. Invoice 5. Measure These items do not represent objects, roles, or categories, and would therefore not be suitable as potential classes in object-oriented programming.

Key concepts

Problem Domain

Understanding the problem domain is the cornerstone of object-oriented programming. Imagine the problem domain as a playground where real-world entities, behaviors, and interactions take on a digital life. It's a realm you're tasked to represent in code by identifying what exists (like players and tools) and what happens (like game rules and actions).

In our exercise, the list includes a mix of entities and actions within a hypothetical veterinary or medical setting. Entities like 'Animal,' 'Medication,' and 'Patient' represent potential actors or objects around which the domain revolves. These are the 'nouns' of the domain, the tangible and conceptual things that our software will need to address. Actions, on the other hand, are operations performed, often represented as methods within the classes.

By zeroing in on the entities, we can lay the groundwork for building meaningful classes that interact within the defined playground, ensuring our code reflects the complexity and reality of the problem domain.

Potential Classes

When we talk about potential classes, we're essentially scouting for the building blocks of our object-oriented design. Classes are blueprints that define the nature (attributes) and capabilities (methods) of the objects that will be created. They are the fundamental components you’ll manipulate to construct your program.

From our list, items like 'Doctor,' 'Nurse,' and 'Client' scream potential classes because they are key players in the scenario described. What makes them stand out as classes is their potential to hold unique information and perform specific tasks.

Why Entities Make Good Classes

• Containment of Information: Entities like 'Nurse' or 'Medication' can encapsulate data, such as a nurse's schedule or a medication's dosage instructions.
• Reusability: Once defined, a 'Doctor' class can be reused for each individual doctor in the system, with their respective attributes.
• Versatility: Classes such as 'Patient' can interact with others, for instance, receiving medication or being invoiced.

Identifying potential classes is about seeing the inherent structure in the chaos of a problem domain, then crafting that structure into code.

Object-Oriented Analysis

Diving deeper, object-oriented analysis (OOA) is the process where we disentangle a problem domain to understand which classes should be defined, and how they should interact. It's detective work: separating the essentials from the noise.

In the process, actions like 'Inoculate' or 'Measure' might feel important, and they are, but not as classes. Here, OOA reminds us that these serve better as methods within a class – they're the verbs that describe what our objects can do.

Focus on Responsibilities

During OOA, we start attributing responsibilities to our potential classes. For example, it's not just any object that can 'Operate'; it's likely a 'Doctor' or a 'Surgeon' class that carries out this task. Additionally, by categorizing related methods appropriately, we avoid unnecessary complexity and enhance clarity.

OOA sets the foundation for robust object-oriented design. By scrutinizing the problem domain and understanding the potential classes, we build a skeleton on which the muscle of our program can efficiently function, ensuring every piece of code has a clear purpose and place.