XML Server Getting Started
Building server side objects for XML over HTTP access from client
As mentioned in the section
Accessing server side objects from the client code: XML over HTTP calls
XMLSP technology
enables developers to delegate server specific code to callable objects on the Application Server side. Since the protocol of
passing arguments and return values to these objects is XML (over HTTP) the server side Java code has to be capable of
parsing XML and manipulating the XML document. Given the fact that J2EE Application Servers do not standardize on the
XML/XSL engines, XMLSP technology currently adopts Xerces and Xalan from Apache as the XML parser and
XSLT/XPath engine of choice.
During the installation of XMLSP software corresponding Apache jars get added to relevant folders of the Application
Server. Some Application Servers may have
xerces.jar
and
xalan.jar
as part of the very Application Server setup. Also, in
certain cases XMLSP installation elect to unzip
xerces.jar
and
xalan.jar
into corresponding
classes
folder. At any rate,
please keep in mind that approximately every three months there are newer releases of
Xerces J bin.zip
available at
http://xml.apache.org/dist/xerces j
and there are release of
Xalan J bin.zip
available for download at
http://xml.apache.org/dist/xalan j
. The download files contain run time files
xerces.jar
and
xalan.jar
, along with samples
and documentation. You can also view Xerces documentation on line at
http://xml.apache.org/xerces j/api.html
. Xalan
documentation is available for on line viewing at
http://xml.apache.org/xalan j/api.html
.
The following example, located at
/Examples/jsp/EchoLogon.jsp
upon installation of XMLSP software on your server, works
in tandem with the login page
/Examples/step5.jsp
. This JSP anticipates to be invoked with the following request stream:
userid value
password value
In return, it is supposed to send
,
if combination of userid and password is validated and
error or exception description
in the opposite case or in case of an exception.
EchoLogon.jsp
is utilizing Xalan XPath engine, however, it does it with the additional help of convenience class
com.cti.xmlsp.XPathAPI
. (see Appendix C for full source code of
com.cti.xmlsp.XPathAPI
).