1. SOEN 343 Software Design
Computer Science and Software Engineering Department
Concordia University
Fall 2004
Instructor: Patrice Chalin

2. Agenda – Lecture 10a Review & renew. Controller Patterns
Some solutions to exercise set 9.
Controller Patterns
GRASP EA
11/10/2018
SOEN 343, © P.Chalin,

3. Do-it-all Servlet Redesign solutions: lect09.ppt SOEN 343, © P.Chalin,
11/10/2018
SOEN 343, © P.Chalin,

4. Presentation Domain Data Source Controller Patterns Page Controller
Template View
Presentation
Front Controller
Transform View
Domain Model
Transaction Script
Domain
Data Mapper
Active Record
Table Module
Data Mapper
Row Data Gateway
Table Data Gateway
Data Source
Table Data Gateway
11/10/2018
SOEN 343, © P.Chalin,

5. Page Controller
11/10/2018
SOEN 343, © P.Chalin,

6. A1 Page Controllers protected void processRequest(
HttpServletResponse response)
throws ServletException, java.io.IOException // {
TaskListHelper helper = new TaskListHelper();
try {
ViewTaskListTS.execute(helper);
} catch (Exception e) {
helper.appendStatus(e.toString()); }
if (helper.getTaskList() == null) {
request.setAttribute("errorMessage", helper.getStatus());
forward("Error.jsp", request, response);
} else {
request.setAttribute("helper", helper);
forward("TaskManager.jsp", request, response);
11/10/2018
SOEN 343, © P.Chalin,

7. A1 Page Controllers protected void processRequest(…) throws … {
TaskListHelper helper = new TaskListHelper();
try {
ViewTaskListTS.execute(helper);
} catch (Exception e) {
helper.appendStatus(e.toString()); }
if (helper.getTaskList() == null) {
request.setAttribute("errorMessage", helper.getStatus());
forward("Error.jsp", request, response);
} else {
request.setAttribute("helper", helper);
forward("TaskManager.jsp", request, response);
11/10/2018
SOEN 343, © P.Chalin,

8. Page Controller vs. Front Controller – Differences in URL
11/10/2018
SOEN 343, © P.Chalin,

9. Page Controllers for A1 http:/stu.cs/343A1/ViewTaskList …
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SOEN 343, © P.Chalin,

10. Front Controller for A1 Base URL: http:/stu.cs/343A1/frontController
…/frontController ?command=ViewTaskList
…/frontController ?command=AddTaskGrade&title=abc&…
11/10/2018
SOEN 343, © P.Chalin,

11. Front Controller
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SOEN 343, © P.Chalin,

12. Front Controller
11/10/2018
SOEN 343, © P.Chalin,

13. Front Controller (Fowler) Command (GoF) Patterns
FrontCommand
+ init ( )
+ processRequest ( )
RemoveStudentCommand
ViewStudInfoCommand
+ processRequest ( )
+ processRequest ( )
11/10/2018
SOEN 343, © P.Chalin,

14. Front Controller: Sequence Diagram
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SOEN 343, © P.Chalin,

15. Front Controller: ProcessRequest
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SOEN 343, © P.Chalin,

16. Front Controller (cont’d)
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SOEN 343, © P.Chalin,

17. Assignment 2: Front Controller Solution
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SOEN 343, © P.Chalin,

18. Front Controller: Advantages?
11/10/2018
SOEN 343, © P.Chalin,