J2EE for Enterprise Integration - Guide to Cloud Computing for Business and Technology Managers - page 140

Web
browser

Entity
bean

Servlet

Database

HTTP
request

JDBC

Session
bean

Wireless
device RMI RMI/

local
inter-
face

J2EE
connector

Enterprise
application

JSP

HTTP
response

B2B Web
Service
client

Service-
based
architecture

Business
object
architecture

User
interaction
architecture

Web
container

EJB
container

Enterprise
information
tier

Client
tier

Middle
tier

FIGURE 6.1
Enterprise application in J2EE.

and business logic associated with a particular entity, including persistence
of that data into a relational database. In J2EE platform, this is typically
implemented as a combination of regular Java classes and Entity beans in
J2EE application. The database access can be implemented by the container
in the case of CMP (Container-Managed Persistence) Entity Beans or by the
developer in the case of BMP (Bean-Managed Persistence) Entity Beans or
regular Java classes. The persistence of each business object is abstracted
out to the extent possible so that separate data objects, persistent frame-
works, or CMP services can be used to affect the data object persistence in
the database.
A major portion of the reference architecture is a generic and configurable
implementation of the Model 2 architecture discussed later in the following
section.

6.2.2 Realization of the Reference Architecture in J2EE

The Java Enterprise Edition (J2EE) platform provides a component-based
approach to implement n-tier distributed enterprise applications. Figure 6.1
shows how the J2EE components provide the implementations for the differ-
ent layers of the reference architecture.