Design And Implementation Of A Student Chat Information System

Here student and lecturer are the main objects and as well as actual user of the system and student chat information System is the class of all this similar objects.
3.6.1    Use Case Diagram: The use case model of any system consists of a set of “use cases” The purpose of a use case is to define a piece of coherent behaviour without revealing the structure of the system. In use case diagram each case is represented by an ellipse with the name of the use case written inside the ellipse. All ellipse of a system is enclosed within a rectangle, which are the system boundary and the different user of the system by the stick person icon.
As shown in Figure 3, there are 2 actors: student and lecturer and 5cases.
The roles of lecturer are login with proper registration into the system, upload or delete only his / her account related materials, add assignments, participate in discussions. The role of a student is login with proper registration into the system and selects the course that he/she desire to learn from the system, download/submit assignments and course materials.
3.6.2    Class Diagram: It models the static view of the system. It comprises of the classes, attributes, methods and relationships between them. It also has visibility which are: (-) for private that cannot be seen by another class, (+) for public that can be seen conventionally, (~) for package that can be used by any other class as long as it is in the package and (#) for protected that can only be
seen by the same class or sub-class.
As shown in Figure 4, we have 2 major packages which are the student and lecturer called the parent objects. The course and discussion is child object which cannot exist without the existence of the parent objects.
3.6.3    Activity Diagram: It visually presents a series of actions or flows in system and it is similar to flowchart diagram. They can also describe the steps in a use case diagram.
As shown in Figure 5, it displays a typical event of managing a course.
When the lecturer enters a course the system automatically checks to see if it is a new course or existing course. If it is a new course, the lecturer creates the course and manages it, while if it is an existing course, two decisions can be a made which are: (i) remove the course or (ii) Modify the course.