Teach Yourself e.net - Syspro

6.1.2.1. XSLT as a Template
XSLT is important for transforming the XML output of the SYSPRO business objects for
use in other applications and settings. In order to gain a better understanding of XSLT, it's
important that we define what an XSLT document contains. Although XSLT stands for
Extensible Stylesheet Language Transformations, another name for it could be "Extensible
Template Language Transformations". This is because XSLT relies on templates to
process and create the particular output structure. The W3C provides the following
statement about XSLT in relation to templates:
“A stylesheet contains a set of template rules. A template rule has two parts: a pattern
which is matched against nodes in the source tree and a template which can be instantiated
to form part of the result tree. This allows a stylesheet to be applicable to a wide class of
documents that have similar source tree structures.”
I'm sure that you have used templates in another application (i.e. MS Word) and so will
know that they provide the basic structure that can be reused for specific purposes.
Templates function in much the same way in XSLT, except that they are programmed to
match up with nodes within an XML document. XSLT templates allow us to process and
structure the data contained within the elements and attributes of the source XML
document. They provide a template structure that can be processed when a particular node
in the source XML document is matched.
Remember that the XSLT processor described earlier is provided with two tree structures
to use when transforming. The first is the structure for the source XML document and the
second is the XSLT template document. Once these two structures are loaded, the XSLT
processor attempts to match the element or attribute names found in the source XML
document with templates contained in the XSLT document. The matching process is
performed using XPath expressions that are part of the XSLT document. When a node
from the source XML document matches a template in the XSLT document, the data
contained in that node gets processed though the template.
The use of XSLT definition files as templates offers an effective way to process various
XML document structures. Each element, attribute, text node, or whatever, can be
matched up with the appropriate template via the XPath expressions. If a given node does
not have a matching template, no processing will occur for it, and the next section of the
source XML document will be processed. When a matching node is found, the template
takes care of creating the proper output structure based on information contained within
the node.
The theory of using XSLT to transform XML is very powerful, but let's begin to apply it
to transforming XML to HTML so that we can use the XmlOut data returned from the
SYSPRO e.net solutions business objects in a web-based application.
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