Chapter 2. J2EE programming model 47
Some benefits of deploying to a J2EE compliant architecture include:
򐂰 A simplified architecture based on standard components, services, and
clients, that takes advantage of the write-once, run-anywhere Java
technology.
򐂰 Services providing integration with existing systems, including Java DataBase
Connectivity (JDBC); Java Message Service (JMS); Java Interface Definition
Language (Java IDL); the JavaMail API; and Java Transaction APIs (JTA and
JTS) for reliable business transactions.
򐂰 Scalability to meet demand, by distributing containers across multiple
systems and using database connection pooling, for example.
򐂰 A wide selection of application development tools and components from
vendors providing standard solutions.
򐂰 A flexible security model that provides support for integration with legacy
security schemes and a unified approach to securing application
components.
WebSphere Application Server
As the foundation of the WebSphere software platform, WebSphere Application
Server reinforces its reputation as the premier, Java technology-based Web
Application Server integrating enterprise data and transactions with the dynamic
e-business world. WebSphere Application Server provides a rich e-business
application deployment environment with a set of application services that
include enhanced capabilities for transaction management in a heterogeneous
environment: comprehensive Web services support, increased security,
performance, availability, connectivity, and scalability.
This section describes the versions of Application Server and highlights their
differences, and then describes the architecture with an explanation of each
component of Application Server.
WebSphere versions
Application Server is packaged based on a single code base to offer developers
a choice of multiple deployment options from single server (Express) to clustered
highly available high volume configurations (Enterprise).
Table 2-4 lists four versions of Application Server and their differences.
WebSphere Application Server also runs on z/OS® and iSeries™ platforms.
Only the distributed versions are listed in Table 2-4.
48 WebSphere Version 5 Application Development Handbook
Table 2-4 Differences among Application Server editions
Feature/Function
Express
Advanced
Edition
(Base)
Network
Deployment
Enterprise
Full J2EE 1.3 support Web
container
only
XX X
Web Services (WSIF,
UDDI4J)
X XX X
XML & XSL X
XX X
LDAP/LTPA/SSO X
XX X
Web Console & Command
Line Admin
X XX X
HTTP server plug-in
XX X
IBM’s HTTP Server (IHS)
included
XX X
Performance Monitoring
(PMI) & Performance Viewer
XX X
Dynacache
XX X
WLM/Failover
XX
Clustering XX
WebSphere Edge
Components
XX
IBM Directory Server
included
XX
Web Services Gateway &
UDDI Registry
XX
Web Services Gateway Filter
X
Programming Model
Extensions
X
MQSeries® included
X
Scalability Limited
to 4
CPUs
Unlimited
CPUs
Unlimited
CPUs &
Servers
Unlimited
CPUs &
Servers
Chapter 2. J2EE programming model 49
WebSphere Application Server architecture
This redbook exploits the features and functions of Application Server Advanced
Edition. This section provides a discussion of the architecture of Application
Server Advanced Edition and its main components.
Figure 2-4 shows Application Server implementations of J2EE.
Figure 2-4 WebSphere Application Server architecture
Node
A node is a logical grouping of WebSphere managed server processes that
share common configuration and operational control. In the Application Server,
each Application Server is responsible for its own configuration in the
configuration repository.
The node agent monitors application servers on a host system and routes
administrative requests to servers. The node agent remains inactive until it is
added to a clustered environment.
Config
repository
(file)
Web
browser
client
EJB container
Embedded JMS Server
Node
Agent
Node
Java
client
Client container
Application
Database
Admin service
Admin
UI
Scripting
client
HTTP server
WebSphere
plug-in
Name Server (JNDI)
Security server
Application Server
Web Container
J2C container
Customer
application (ear)
Web
Services
engine
Admin
application

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