Use Case Design

Research

To write a use case, follow these steps:

1. Identify the actors:

   - Determine who or what will be interacting with the system (e.g., users, administrators, external systems).

2. Define the goal:

   - Clearly state the goal the actor wants to achieve by using the system.

3. Write the main success scenario:

   - Describe the steps the actor takes to accomplish the goal under ideal circumstances.

   - Be specific and outline the interaction between the actor and the system.

   - Numbering the steps can help keep the use case organized.

4. Include alternative paths:

   - Consider other ways the actor might achieve the same goal.

   - Describe these alternative paths and the conditions under which they might occur.

5. Describe exception paths:

   - Think about what could go wrong during the main success scenario.

   - Write down how the system should handle these exceptions and what the actor should do in these cases.

6. Add preconditions and postconditions:

   - Preconditions: State any conditions that must be true before the use case can begin.

   - Postconditions: Describe the state of the system after the use case has been successfully completed.

7. Review and refine:

   - Read through the use case to ensure it's clear, concise, and easy to understand.

   - Make sure all necessary information is included, and revise as needed.

Here's a simple template for a use case:

```

Use Case: [Title]

Actor: [User, Administrator, External System]

Goal: [What the actor wants to achieve]

Preconditions:

1. [Condition 1]

2. [Condition 2]

Main Success Scenario:

1. [Step 1]

2. [Step 2]

3. [Step 3]

Alternative Paths:

1a. [Alternative Step 1]

1b. [Alternative Step 2]

Exception Paths:

2a. [Exception Condition]

   1. [Exception Handling Step 1]

   2. [Exception Handling Step 2]

Postconditions:

1. [Condition 1]

2. [Condition 2]

```

Remember, use cases should be written in a clear, concise manner and focus on the user's perspective. They serve as a communication tool between stakeholders and developers to ensure that the system being developed meets the users' needs.