Virtual ClassroomIntegrated Learningenvironment over internet               Anshu Veda               Prajakta Kalekar     ...
The Client   This project has been sponsored by    Intel   IIT B point of contact    Prof. Umesh Bellur
Problem Definition This project aims at putting together an integrated e-Learning environment for a university student. Th...
Basic terminology   RMI (Remote Method Invocation)    Server application creates remote objects, makes references to them...
EJB Architecture
Basic Terminology   CMP – Container Managed Persistence       EJB container takes care of making sure the        entity ...
Requirement Specs   The system will be having 3 roles:       Instructor       Student       Admin   Admin       Mana...
Technology Decisions                  Client   Client         •Integrated Environment                 Communication Protoc...
Thin v/s Thick ClientFeature   Thin Client              Thick ClientWeb         Different Browsers      Gives integrated...
Initial Architecture Diagram     Swing Client                       Specs                          Client- Swing         ...
Pros and ConsPros Simple        Simple and Intuitive. Uses HTTP over the internet         and simple JDBC to communicate...
WebServices ???   RMI offers an order of magnitude better    performance than other alternatives, being at    least 8.5 t...
Why EJBs?   Container inherently provides    features such as     Security     Transaction   Management     Persistenc...
CMP vs BMP              BMP                CMPAvoid         Done using dirty   CMP engineunnecessary   flags, but it      ...
Architecture Diagram         (The chosen approach)            SessionBean             Session bean                        ...
Session Facade   Performance      An Entity bean is equivalent to a row in the database. If       the Entity beans were ...
Session Facade   Reusability      The session bean layer is powerful because it       externalizes all business logic fr...
E-R Diagram
Object Model
Collaboration Diagram - Login
Collaboration Diagram - Registration
Sequence Diagram - Registration
Collaboration Diagram – Set Quiz
Class Diagram
Class Diagram (old & new)
Lessons learnt / Challenges faced   1. Familiarity with J2EE     Studying  EJB Architecture (session      bean, entity b...
Challenge Tryingto synchronize the Intel deadlines with the syslab deadlines throughout this course 
Deployment Descriptor<entity>   <ejb-name>course</ejb-name>   <local-home>vclassroom.course.ejb.CourseLocalHome</local-  h...
Deployment Descriptor<query>    <query-method>          <method-name>ejbSelectprerequisites</method-name>          <method...
Technologies / Tools / MethodologiesLearnt   J2EE Architecture     Enterprise   Java Beans   JBoss 4.0   Postgres 8.0...
The Timeline   Before MidSem       Overview of the system requirements from Intel       Requirement Specification Docum...
Thank you !!!!
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Virtual classroom

  1. 1. Virtual ClassroomIntegrated Learningenvironment over internet Anshu Veda Prajakta Kalekar Shruti Mahambre
  2. 2. The Client This project has been sponsored by Intel IIT B point of contact Prof. Umesh Bellur
  3. 3. Problem Definition This project aims at putting together an integrated e-Learning environment for a university student. This will also be used by distance education programs offered by institutes, in order to enable students to avail of the academic facilities from any computer connected to the internet.
  4. 4. Basic terminology RMI (Remote Method Invocation) Server application creates remote objects, makes references to them available and allows clients to invoke methods on these remote objects. RMI tunneling over HTTP Combines the benefits of HTTP tunneling and RMI over internet EJB  Session Beans (verb) Model business processes. They represent actions  Entity Beans (noun) Model Business data – They are data object, java objects that cache database information EJB Container  House enterprise beans and make them available for clients to invoke remotely  Provide an environment in which enterprise beans can run  “Invisible middlemen”
  5. 5. EJB Architecture
  6. 6. Basic Terminology CMP – Container Managed Persistence  EJB container takes care of making sure the entity bean object stays around. BMP – Bean Managed Persistence  You as the bean programmer can take over the responsibility of managing the "persistence" of the data -- of where the data stays when the server is not running or when the bean is not in memory.
  7. 7. Requirement Specs The system will be having 3 roles:  Instructor  Student  Admin Admin  Managing user accounts, course registration approval Instructor  Login,Create / Modify course details, set Quizzes, assign grades Student  Login, Register / Unregister for courses, take quizzes, view lectures in offline mode Non-Functional Requirements  Open-Source and Freeware  Support over Internet and Intranet
  8. 8. Technology Decisions Client Client •Integrated Environment Communication Protocol Internet •Cross firewall •Intranet and Internet support Server •Transaction Server •Persistence •Security •Caching
  9. 9. Thin v/s Thick ClientFeature Thin Client Thick ClientWeb  Different Browsers  Gives integrated lookBrowser may require different and feel. The client plug-ins to support executable, installableVs features such as Video from web, can bundle allJava streaming. prerequisites.  Look and feel varies  Java Swing client givesClient from browser to same look and feel across browser. all the platforms (as compared to web browser).Speed Slow. Everything must Fast. Can instantly scroll wait for the server to since the client can cache process and transmit and process data locally. the next screen of information.
  10. 10. Initial Architecture Diagram Swing Client Specs  Client- Swing  Servlet Container- Tomcat3.2 Servlet  DB Server- Postgres8.0 Request Processor DB Manager Database
  11. 11. Pros and ConsPros Simple  Simple and Intuitive. Uses HTTP over the internet and simple JDBC to communicate with the database server. Light  As compared with J2EE serverCons Plain Http protocol – No type safety No caching Support No Transaction Management Support. Absence of Distributed Objects.
  12. 12. WebServices ??? RMI offers an order of magnitude better performance than other alternatives, being at least 8.5 times faster than Web Services HTTP-to-servlet is more than 4 times slower than web services. Reference: “Java RMI, RMI Tunneling and Web Services Comparison and Performance Analysis” - Matjaz B. Juric, Bostjan Kezmah, Marjan Hericko, Ivan Rozman, Ivan Vezocnik
  13. 13. Why EJBs? Container inherently provides features such as  Security  Transaction Management  Persistence  DistributedObject Support that goes well with RMI.
  14. 14. CMP vs BMP BMP CMPAvoid Done using dirty CMP engineunnecessary flags, but it handles thisstores requires more coding and is error-proneCoding JDBC sql queries Lesser Coding have to be code.
  15. 15. Architecture Diagram (The chosen approach) SessionBean Session bean EntityBean SessionBean EntityBean Database SessionBean EntityBeanclient SessionBean EntityBean
  16. 16. Session Facade Performance  An Entity bean is equivalent to a row in the database. If the Entity beans were to be accessed directly, a network call would result for each row access.  On the other hand, a Session bean is equivalent to a stored procedure. Accessing a session bean that is co- located with an entity bean emulates accessing a row through a stored procedure.
  17. 17. Session Facade Reusability  The session bean layer is powerful because it externalizes all business logic from the entity beans. This means the entity beans contain data and data- related logic only.  This promotes high re-use of entity beans. Data abstraction layer  The session bean layer is a facade. The particular way the session bean persists (via JDBC directly or via entity beans) is an implementation detail of the session bean. The decision about whether to use JDBC or entity beans can be deferred until a later date.
  18. 18. E-R Diagram
  19. 19. Object Model
  20. 20. Collaboration Diagram - Login
  21. 21. Collaboration Diagram - Registration
  22. 22. Sequence Diagram - Registration
  23. 23. Collaboration Diagram – Set Quiz
  24. 24. Class Diagram
  25. 25. Class Diagram (old & new)
  26. 26. Lessons learnt / Challenges faced 1. Familiarity with J2EE  Studying EJB Architecture (session bean, entity bean concepts)  BMP vs CMP  Concept of CMR  Configuring JBoss 4.0  Configuring Postgres 8.0 on JBoss  Serial – Primary Key  Writing Deployment Descriptors
  27. 27. Challenge Tryingto synchronize the Intel deadlines with the syslab deadlines throughout this course 
  28. 28. Deployment Descriptor<entity> <ejb-name>course</ejb-name> <local-home>vclassroom.course.ejb.CourseLocalHome</local- home> <local>vclassroom.course.ejb.CourseLocal</local> <ejb-class>vclassroom.course.ejb.CourseBean</ejb-class> <persistence-type>Container</persistence-type> <reentrant>False</reentrant> <cmp-version>2.x</cmp-version> <abstract-schema-name>course</abstract-schema-name> <prim-key-class>java.lang.Integer</prim-key-class> <primkey-field>courseId</primkey-field> <cmp-field> <field-name>courseId</field-name> </cmp-field>
  29. 29. Deployment Descriptor<query> <query-method> <method-name>ejbSelectprerequisites</method-name> <method-params> <method-param>java.lang.Integer</method- param> </method-params> </query-method> <ejb-ql><![CDATA[SELECT OBJECT(p) FROM course as c, IN(c.prereqCourses) p WHERE c.courseId = ?1]]> </ejb-ql> </query> </entity>
  30. 30. Technologies / Tools / MethodologiesLearnt J2EE Architecture  Enterprise Java Beans JBoss 4.0 Postgres 8.0 EJB-QL Swing (work in progress) Patterns – Session Façade, Recursive Meta pattern, Chain of responsibility
  31. 31. The Timeline Before MidSem  Overview of the system requirements from Intel  Requirement Specification Document – prepared and presented to Intel  Architecture + Design Documentation  Prototype : Demo – with the old architecture – Login, Registration, Quiz  Deliverable – Client + Server implementation of modules After Midsem  Change in architecture – Protocol + Server Side  Learning Curve for new technology – EJBs, J2EE architecture  Technology survey - Exploring options like JDO, Web Services  Configurations – JBoss 4.0, Postgres 8.0  Design of new architecture – Presentation to Intel  Detailed Design specification documentation  Deliverable – Server Side coding + documentation – Login, Registration, Quiz
  32. 32. Thank you !!!!

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