Monday, 27 September 2010

Templates in BPEL Transforms

Multiple times I encountered that the Transformation tool of de BPEL designer has difficulties to cope with xpath and xslt functions in the stylesheet that it does not 'know'.
We have for example some custom xslt functions and I use some xpath 2.0 functions. And if I use them and deploy the process, they'll work. But for the mapper -tool the transform is invalid and it will not show the transformation map.

This is especially true for BPEL 10.1.2 that is still used at my current customer (there is a upgrade to 11g project on going).

Very anoying, because we have some large xsl's that use a large number of custom xslt-functions to do a cached dvm lookup.

But today I found a very nice workaround. If you hide those functions in a custom user template then the transformation map does not have difficulties with it.


I now have the following user-defined template (put at the bottom of the xsl stylesheet):

<xsl:template name="TransformLandCode">
<xsl:param name="landCode"/>
<xsl:comment>Transform Landcode gebruikmakend van cache:lookup
</xsl:comment>
<xsl:variable name="result" select="cache:lookup($landCode,&quot;LandCodeDomain_<FromSystem>To<ToSystem>&quot;)"/>
<xsl:value-of select="$result"/>
</xsl:template> 

So where I had something like:
<xsl:value-of select="cache:lookup(/ns1:rootElement/ns1:subElement/ns1:LandCode,&quot;LandCodeDomain_&lt;FromSystem&gt;To&lt;ToSystem&gt;&quot;)"/>

I now call the template:
<xsl:call-template name="TransformLandCode">
<xsl:with-param name="landCode" select="/ns1:rootElement/ns1:subElement/ns1:LandCode"/>
</xsl:call-template>


Nice is by the way that the mapper also allows for adding the call statement in to the map using drag and drop. Also the parameters can be filled using dragging the lines:




And of course you can add code-snippets for it.

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