Sequence Diagrams

Sequence Diagram 1

Name: Sign Up

Actor: Guest

Goal: Registering to the system

Steps:

1. Guest opens the website and clicks "Sign Up" button.
2. Guest enters a unique username, email and a password.
3. Guest chooses a user type: teacher or student.
4. Guest is directed to the homepage
5. Guest receives an email from the system.

Post Conditions:

1. Guest is now a user of the system.

Sequence Diagram 2

Name: Login

Actor: Registered Users

Goal: Login to the System

Preconditions: The user must have been registered.

Steps:

1. User opens the website and clicks "Login" button.
2. User enters his username or email and password.
3. The system checks the validity of the inputs.

Post Conditions:

1. If the user's inputs are valid, the user is directed to the homepage.
2. If the user's inputs are not valid, the user receives an error message, and stays on the login page.

Sequence Diagram 3

Name: Search

Actor: Registered Users

Goal: Search a topic.

Preconditions: The user must have been registered.

Steps:

1. User opens the website.
2. User enters the search text on the search box and clicks the search button.
3. The system finds the relevant topics.

Post Conditions:

1. If at least one topic is found according to the search keyword, the system lists these topics.
2. If no topic is found, the user receives an error message.

Sequence Diagram 4

Name: Create Topic

Actor: Teacher

Goal: Create a topic.

Preconditions: The user must have been registered and must have a teacher account.

Steps:

1. User opens the profile page or homepage.
2. User click the "Create a Topic" button.
3. User is directed to the create topic page.
4. User enters the inputs for the new topic.
5. User enters the "Create the Topic" button.
6. The system checks the validity of the inputs.

Post Conditions:

1. If all the inputs correct, the topic is created.
2. If not all inputs are entered, the user receives an error and the system doesn't create a new topic.

Sequence Diagram 5

Name: Add Comment

Actor: Registered User

Goal: Add Comment.

Preconditions: The user must have been registered.

Steps:

1. User opens a topic page and clicks the discussion page.
2. User chooses "Reply" button on a comment or enters the comment text on the comment box.
3. If reply button is chosen, the comment text box opens and user enters the comment text.
4. User clicks "Send Comment" button.
5. The system creates the comment.

Post Conditions:

1. If the comment is a reply to another comment, the new comment is displayed under the replied comment.
2. If the comment is a new comment in the discussion page, the new comment is displayed under other comments.

Sequence Diagram 6

Name: Follow a Topic

Actor: Registered User

Goal: Follow a topic

Preconditions: The user must have been registered.

Steps:

1. User opens homepage or search page.
2. User chooses a topic and click "View Topic" button.
3. User is directed to the topic page and
4. If the user is not following the topic yet, user can see "Follow Topic" button.
5. User clicks "Follow Topic" button.
6. The system makes the necessary updates.

Post Conditions:

1. The user is now following the topic.

Sequence Diagram 7

Name: Add a New Tag

Actor: Teacher

Goal: Add a New Tag to Topic

Preconditions: The user must be a Teacher.

Steps:

1. Teacher opens profile page.
2. Teacher chooses a topic created by him.
3. Teacher is directed to the topic page
4. Teacher clicks "Add Tag" button.
5. Add New Tag Window will be open.
6. Teacher writes the New Tag and clicks "Add" button.
7. The system checks whether the Tag is used before.

Post Conditions:

1. If the New Tag is used before an error window will be shown to User.
2. If the New Tag is not used before the tag will be added and a window will be shown about success.