object  Roster
   components: Attendance*;
   operations: AddStudent, EditStudent, RemoveStudent,LoadRoster,ViewScreen,GrantAccess;
   description: (* Roster is a dialogue with the collection of students names that are enrolled
                in the class. It contains operations for the instructor to add/edit/remove 
                students as well as loading a roster. It also has operation that grants
                students drawing access and view student screen.  
    
   *);
end InstructorRoster;

object Attendance
   components: Name and Status and Time;
   description: (* Attendance is the component of Roster that stores information of students 
                that are enrolled in the class. The name component is the student's real name.
                The status component tells whether the student is signed on or signed off. The
                Time component reports the students' sign on time. 
   *);
end Attendance;

object Name = string;
object Status = string;
object Time = string;

operation AddStudent
   inputs: Name, Id;
   outputs: ;
   precondition:(* The student's name cannot be NULL and the student's ID has to be numerical values*);
   postcondition:(* A new student has been added to the database and the student's name will appear 
                on the roster attendance list *);
   description:(* Adds a new student to the current roster *);
end;

operation EditStudent
   inputs: Name, Id ;
   outputs: ;
   precondition:(* Name cannot be null and Id has to be numerical values *);
   postcondition:(* The student's information has been edited and saved in the database. 
                 The new name will appear on the roster attendance *);
   description:(* Edits the Name and Id of the student *);
end;

object Id = int; 

operation RemoveStudent
   precondition:(* A name of the student on the roster list must be selected *);
   postcondition:(* Student has been removed from the roster *);
   description:(* Removes a student from the roster *);
end;

operation LoadRoster
   inputs:  ;
   outputs: ;
   precondition:(* A roster file type '.rst' must exist *);
   postcondition:(* The roster list is loaded to the attendance list *);
   description:(* loads a roster from a .rst (roster) file *);
end;

operation ViewScreen
   inputs:  ;
   outputs: ;
   precondition:(*A name of the student on the roster list must be selected *);
   postcondition:(* The instructor screen displays the screen of that selected student *);
   description:(* views the screen of a selected student *);
end;

operation GrantAccess
   inputs:  ;
   outputs: ;
   precondition:(* a student name on the attendance list must be selected*);
   postcondition:(* student's drawing will now appear on all screens *);
   description:(* grats the selected student access to draw *);
end;

object UserAccess
   components: Mode*;
   description: (* UserAccess allows the instructor to set different accessing mode for the
                students. These modes determine how much access the students have over their
                workstations.
                *);
end UserAccess;

object Mode
   components: FreeAccess or LectureOnly or EnableProgram or Disable;
   precondition: (* None yet *);
   postcondition:(* Once a mode is selected, the current mode will change to the selected mode *);
   description:(*The Mode object allows the intrucstor to select an access mode for the students. 
               The four modes are FreeAccess, LectureOnly, EnableProgram, and Disable *);
end Mode; 
   
object FreeAccess
   components: Access*;
   precondition:(* None yet *);
   postcondition:(* The useraccess mode is changed to free access*);
   description:(*This is a mode that grants the students all access to their workstation*); 
end FreeAccess;

object LectureOnly
   components: Access*;
   precondition:(* None yet *);
   postcondition:(* The useraccess mode is changed to lecture only*);
   description:(*This is a mode that only allows e-Class lecture application to run in the students workstation*); 
end LectureOnly;

object EnableProgram
   components: Access*;
   precondition:(* None yet*);
   postcondition:(* The useraccess mode is changed to Enable Program *);
   description:(*This is a mode that allows the instructor to allow selective applications
               for the students to use along with the lecture.
               *); 
end EnableProgram;

object Disable
   components: Keyboard and Mouse;
   precondition:(* None yet *);
   postcondition:(* The useraccess mode is changed to Disable Mode and the user must
                 select either Keyboards and/or Mouse to disable *);
   description:(*This is a mode that allows the instructor to disable either the Keyboards and/or mouse
                in the students workstations. 
              *); 
end Disable;

object Access
   component: AccessType;
   precondition: (* A type of mode must be selected *);
   postcondition:(* The access is changed to the access type contains in Mode *);
   description: (* The Access component contains that actual code that sets the actual mode *);
  
end Access;

object AccessType = String;

object Keyboard
   components: Access*;
   precondition( * The 'Disable' mode must be selected *);
   postcondition( * All keyboards in the students' workstations are now disabled*);
   description: (* The keyboard component disables all the students' keyboards access to their 
                workstations *);
end Keyboard;


object Mouse
   components: Access*;
   precondition( *The 'Disable' mode must be selected *);
   postcondition( *All mouse in the students' workstations are now disabled*);
   description: (* The mouse component disables all the students' mouse access to their 
                workstations *);
end Mouse;