You can use an existing XSL style sheet to perform your transformation
if you want to reuse a transformation, or if you have a complex transformation
that's easier to write as an XSL style sheet.
Note: When you use an existing XSL style sheet,
you will need to manage the style sheet yourself. If you refactor your XSL
Transformation primitive, or an XML map, you will need to manually update
the XSL style sheet.
Avoid editing an XSL style sheet that was generated
from an XML map, because if you change the XML map in the XML mapping editor,
the XSL style sheet will be automatically generated, and your changes will
be lost. If you want to customize a generated stylesheet, you
must delete the following line in the generated XSL to prevent the code from
being overwritten:
<!-- generated xmxFile="..." md5sum="..." -->
Follow
these steps to use an existing XSL style sheet, and optionally edit it.
- The style sheet must exist in the mediation module's
project directory before you can select it. Switch to the Physical Resources
view and create or copy the XSL style sheet into the mediation module project.
- In the mediation flow editor, select the XSL Transformation
primitive, and click the Details page in the Properties view. Click the Browse button.
All the available XSL style sheets (xsl), and XML maps (xmx) are listed in
the Mapping File Selection dialog. OK.
- Select the style sheet.

- Select the XSL mapping root. This is the part of the message that
is available to the transformation, both the input and output messages. Select
an option in the list:
- / to transform the complete message.
- /body to transform the message body
- /headers to transform the message headers
- /context to transform the message context
Note: When you select /, /headers or /context as the root, you need to explicitly map all the message sections in the
XML Mapping editor using the Match Mapping menu option. Otherwise, you may
get errors at runtime. See the example below for more information.
- The XSL style sheet now appears in the Mapping file field.
To make changes to this file, click Edit to launch
the XSL Editor.
Example:
The picture
below shows the mapping between the source and target message for the TransformToDelayed
primitive in the XML Mapping editor. The root property was set to /, so the
complete message is displayed in the editor. The input message operation getQuote
has a parameter named request that takes a business object that has an attribute
whose name is symbol. The output message operation has a parameter symbol
of type String. The mapping shown is between the symbol attribute of the input
message to the symbol of the output message.

Since the root was set to /,
all the message sections in the mapping editor must be explicitly mapped.
Click on the top level element (smo) of the source and target, right-click,
and select Match Mapping, as shown in the picture below:

For more information, see Rational® Application
Developer topic Mapping between XML files