Java Reference
In-Depth Information
•
Top-down
: This development strategy involves creating a web service
from a WSDL file. The top-down approach is likely to be used when cre-
ating web services from scratch. It is the preferred choice of "purist" web
service engineers because it's business driven, that is, the contract is
defined by business people and so the software is designed to fit the web
service contract.
•
Bottom-up
: This approach requires the WSDL file to be generated by the
programming interfaces. It is likely to be used when we have existing ap-
plications that we want to expose as web services. As it does not require
a deep knowledge of the WSDL syntax, it is the easiest choice if you want
to turn your Java classes or EJB into web services.
As the audience of this topic is composed mainly of Java developers with little or no
knowledge at all of WSDL basics, we will focus primarily on the bottom-up approach.
Designing top-down web services, on the other hand, will require you to integrate the
basic web services notions provided with this chapter with a comprehensive aware-
ness of the WSDL standard.
JBoss SOAP web services stack
All JAX-WS functionalities provided on top of JBoss Application Server are currently
served through a proper integration of the JBoss web services stack with most of the
Apache CXF
project.
Apache CXF is an open source web service framework that provides an easy-to-use,
standard-based programming model for developing both SOAP and REST web ser-
vices. The integration layer (JBossWS-CXF in short hereafter) allows us to:
• Use standard web services APIs (including JAX-WS) on a JBoss Ap-
plication Server; this is performed internally by leveraging Apache CXF,
without requiring the user to deal with it
• Leverage Apache CXF's advanced native features on top of a JBoss Ap-
plication Server without the need for the user to deal with all the required
integration steps for running the application in such a container
Therefore, the focus of the next section will be developing JAX-WS web services us-
ing the built-in Apache CXF configuration. If you want to further expand your know-
