Comment Module | Read Feature

# Comment Read Process

### User Story:

- When a user (buyer) attempts to read comments for a course with valid details, the user (buyer) will receive a list of comments that have been posted for the specific course.
- if the user (buyer) tries to access comments with invalid details, or provides an invalid courseID or userID, they will receive a message indicating that the comment details could not be found.

### Task

- [x] Implement Data Access Object (DAO) Layer.
- [x] Implement Service Layer.
- [x] Create JUnit Test Cases.
- [x] Ensure that the test cases are passing.
- [ ] Write clear and concise comments in the code to explain complex logic.

### DAO
- listComment()

### Service
- ReadComment()

### Test
TestListCommentFeature
- testListCommentSuccess()
- testListCommentFailure()

# Flowchart
```mermaid
flowchart TD
A[Start]
B[User Requests to Read Comments]
C[Validate CourseID]
D{Validation Successful?}
E[Retrieve List of Comments]
F[Display List of Comments]
G[Display Validation Error]
H[End]

A --> B
B --> C
C --> D
D -- Yes --> E
E --> F
D -- No --> G
G --> H
F --> H

```