How to extract the sequence diagram from the function procedures?

Question

I have a E-services portal for student’s system But I'm not sure which sequence diagram will be drawn for withdrawal from the course

The student can:

• Request apology or reprieve
• Request delete or add course
• Request for re-registration
• Request withdraw from a course

Academic Advisor:

• Request Accept
• Request class expansion

Head of Department:

• Request Accept

Under of Educational Affairs:

• Request Accept

Admission and Registration:

• Request execute

Course withdrawal service procedures:

1. Transfer the application to the student's academic advisor for approval.
2. Transfer the request to the student’s head of department for approval.
3. Transfer the application to the Vice Dean for Educational Affairs for approval.
4. Automatic transfer of the application to the Deanship of Admission and Registration for implementation.

My question is:
Is the sequence diagram drawing correct for the required procedures?
How can I draw a class diagram for this system?
Is the Use case diagram correct?

Answer 1

Is the sequence diagram drawing correct for the required procedures?

First are the messages asynchronous ? The ExecutionSpecifications indicates there are not

it is not correct :

• the explicit returns everywhere indicate calls (because of the "()" ), they must be values, else there are not returns

• if the CourseProfessor cancel the request it is abnormal later ExecuteRequest was called on AcademicAdvisor

• While the SubmitRequest on CourseProfessor is done and return an Accept/CancelRequest it is not possible to have after the call of ExecuteRequest on AcademicAdvisor, That one must be before the return from CourseProfessor in the upper alternate division

• it is the same with the other cases where yuo call Accept/ExecuteRequest while the return was done so the execution finished

• the final return is illegal too, it goes to Student but that one does not called ExecuteRequest on AdmissionAndRegistration