顺序图说明文档.txt

学生注册— 本模块允许新的学生创建和维护他们的帐户信息

Student Logs On to the System：
The student enters a login name and password, and clicks the submit button in the login page. The browser sends an HTTP GET request to the Web server. The URSControllerServlet servlet receives the client request and invokes the validateUser() method of the StudentFacade enterprise bean. The fa?ade delegates the method call of the SignOn authentication component, which uses the User entity bean to look up and validate the login name and password. Finally, the controller servlet forwards the request to the catalog page, which displays the course catalog.



Student Places Order：
when the student clicks the Place Order button in the enrollment cart page, the URSControllerServlet receives the request and invokes the placeOrder() method of StudentFacade. The fa?ade first creates a new order using the Order entity bean. The fa?ade then creates multiple line items using the OrderLineItem entity bean and associates the line items with the order. Finally, the fa?ade sends a JMS message to the Destination using the MessageSender component for order verification purposes.


Administrator Approves Order and Enrolls Student：

When the administrator approves an order placed by the student, he or she clicks the Approve Order button on the administrator page. The URSControllerServlet receives the corresponding request and invokes the method approvedOrder of AdminFacade. The facade retrieves the order by using its primary key, order_id, and changes the order status to Approved. The facade then enrolls the student in all the courses that are part of the order by using the enrollment component. Finally, the fa?ade sends an e-mail to the student confirming the approval.