1. Layers & Tiers
Umair Javed
Lec - 41

2. Layers & Tiers
Layers are merely logical groupings of the software components that make up the application or service.
Whereas tiers refer to the physical residence of those layers (hardware)
In general,
Layers – represents logical view of application
Tiers – represents physical view of application
However, both terms are used interchangeably.

3. Layers
Figure shows a simplified view of one application and its layers.

4. Tiers Presentation Layer Web Layer Business Layer EIS Layer browser
Client machine
Web server
Web Layer
Server machine
Application
server
Business Layer
DB server
EIS Layer
DB machine

5. Layers [1] Presentation layer Collects user inputs
Validates user inputs
Presents the results of a computation
Controls the screen flow

6. Layers [2] Business Layer
Concerned with the application specific functionality
Used to implement business rules and to perform business tasks
For example, in a banking system, banking functions such as opening an account, calculation of Tax, etc.

7. Layers [3]
Data Layer
Concerned with the management of the data & data sources of the system.
Data sources can be database, XML , web services, flat file etc.
Encapsulates data retrieval & storage logic
For example, the address book application needs to retrieve all person records from a database to display them to the user

8. Frameworks(Struts,JSF etc)
Layers Support in Java
Layers
Java/J2EE Technology
Client Presentation
HTML/Applets
JSP / Servlets
Frameworks(Struts,JSF etc)
Server Presentation
Business
JavaBeans / EJB
Data
DAO / Connectors

9. Java 2 Enterprise Edition (J2EE)

10. What is J2EE? Open and standard based platform for:
Development & deployment of n-tier web based and component based enterprise applications
Reusability, enhance-ability, scalability & interoperability

11. J2EE Suite Core technology: Web Technology Platform services
Container infrastructure, language and environment support
Web Technology
Java Servlets
JavaServer Pages (JSP)
JavaServer Pages Standard Tag Library (JSTL)
JavaServer Faces (JSF)
Platform services
Security
Transactions
Resources
Connectors
Java Message Service
And extensive support for
XML technology
Enterprise Java Bean (EJB) technology etc.

12. J2EE Distributed Multi-tiered Applications

13. J2EE : Multi-tiered Applications

14. J2EE : Multi-tiered Applications

15. J2EE : Multi-tiered Applications
servlets

16. Client Tier Communication Options

17. Communication with Business Tier

18. Case Study: Matrix Multiplication
Using Layers

19. Case Study: Matrix Multiplication
Problem Statement
Calculate product of two matrices of order 2 * 2
Result of multiplication should be stored in DB as well as shown to the user.

20. Case Study: Matrix Multiplication
Format
Input format
input will be in 4,2,6,5 format separated by commas where 4,2 represents entries of the first row
Display format
Displays the matrix as a square
Storage format
Matrix will be stored as a string

21. Matrix Multiplication: Layer by Layer View
Client side
Presentation layer
HTML
Matrixresult
.jsp
Matrixinput
.jsp
Server side
Presentation layer
MatrixBeann
ControllerServlet
Controller layer
MatrixMultiplier
Business layer
Data layer
MatrixDAO

22. Case Study: Matrix Multiplication
Example Code
netBeans4.1 Project