NonStop Systems Introduction

The Application Server Environment
NonStop Systems Introduction—527825-001
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WebLogic Server and the J2EE Platform
A J2EE client can be a web client or an application client. Both types of clients provide
a user interface, such as a graphical user interface, and access enterprise beans that
perform the business logic on the business tier.
The container provides an interface between clients and enterprise beans, and
manages the execution of the Beans. An enterprise bean must be placed into a
container and assembled into an application before it can be executed. Enterprise
beans and their container run within the WebLogic Server framework on the NonStop
server. EJB also provides containers for web components, client components, and
applets.
The EJB container together with WebLogic Server provides a run-time environment for
EJB applications that includes many essential run-time services, such as process
management, system resource management, and transaction management. This
simplifies the development process by relieving programmers of the need for writing
their own code for these services. Developers can thus concentrate on the business
model when developing enterprise beans.
The HP implementation of Enterprise JavaBeans, NonStop EJB, provides all the
features of standard EJB combined with the benefits of TMF, SQL/MX, and the
NonStop server.
The NonStop EJB architecture is the J2EE architecture as implemented in WebLogic
Server. This architecture includes APIs that enable programmers to access essential
services used by EJB applications:
•
Java Database Connectivity (JDBC) enables Java programs to access a SQL/MX
database.
•
Java Naming and Directory Interface (JNDI) enables Java clients to connect to
EJB components across a network.
•
Java Transaction API (JTA) provides a high-level interface for controlling
transactions.
•
Servlets and JavaServer Pages provide services for developing and running Web
applications.
Interoperability With Existing Application Servers
You have seen how NonStop Tuxedo and NonStop CORBA provide frameworks for
developing and running ZLE applications and services. WebLogic Server interoperates
with each of these frameworks to extend them with J2EE capabilities. For example, the
WebLogic Tuxedo Connector (WTC) API enables WebLogic Server clients to invoke
NonStop Tuxedo services and NonStop Tuxedo clients to invoke Enterprise JavaBeans
that are running in WebLogic Server. As shown in Figure 3-18 on page 3-28, WebLogic
Server can also integrate with NonStop CORBA (using the IIOP protocol) and Pathway
(through the JPathsend API).