1.3 Enterprise Architecture

1.3 Enterprise Architecture

-          Figure depicts the J2EE as a multitier architecture.

 [Figure : Multitier J2EE architecture. ]

The following gives a brief summary of each tier of the J2EE architecture:

·         Client tier :-

o    This tier interacts with the user.

o    And displays information from the system to the user.

o    J2EE supports different types of clients—both inside and outside enterprise firewalls {including Web clients (HTML and Java applets) and Java applications.}

·         Web tier :-  

o     This tier accepts user requests.

o    And generates responses using the presentation logic.

o    In the J2EE platform, servlets and JSPs in a Web container implement this tier.

·         Business logic tier :-  

o    This tier handles the core business logic of the application.

o    The business components are typically implemented as EJB components.

o    With support from an EJB container.

o    Which provides the component life cycle

o    And manages :

§  Persistence,

§  Transactions,

§  Security, and

§  Resource allocation.

·         EIS tier :-

o    This tier is responsible for the enterprise information systems.

o    Including

§  Different database systems,

§  Transaction processing systems,

§  Legacy (inheritance)systems,

§  Message-Oriented Middleware, (MOM) and

§  Enterprise resource planning systems (ERPs).

o   The EIS tier is the point at which J2EE applications integrate with non-J2EE or legacy systems.