Mapping complex conditions in BizTalk with XSLT

Recently I found myself in a situation where I needed to evaluate a set of complex conditions that I could not use the Business Rules Engine for. The BizTalk mapper was able to achieve the conditionality by chaining a series of about 21 functoids together but this became very unmanageable especially since I was combining false statements to see if both were false, then returning a true to an “And” functoid (&) which evaluated another branch as true and passed a result to the node in the destination schema, you get the idea.

An easier way is to plug in XSLT. There are disadvantages to doing this, the main one being its maintainability and transparency but when faced with the daunting set of functoids described above, it looked a decent option.

The XSLT function that I used was the <xsl:choose> statement, inside the statement was a set of conditions which, if true, would return a value/values to the destination schema. In the last part of the statement was the <xsl:otherwise> condition which could set values if the conditions presented were not valid and you had a default you wanted to present in that event.

<xsl:variable name="var:vAnnuity" select="count(/*[local-name()='InternalSupport' and namespace-uri()='http://internal_support']/*[local-name()='LoanPartItems' and namespace-uri()='' and Method='Annuity'])" />

<xsl:variable name="var:vLinear" select="count(/*[local-name()='InternalSupport' and namespace-uri()='http://internal_support']/*[local-name()='LoanPartItems' and namespace-uri()='' and Method='Linear'])" />

<xsl:variable name="var:vTotalCount" select="count(/*[local-name()='InternalSupport' and namespace-uri()='http://internal_support']/*[local-name()='PartItems' and namespace-uri()=''])" />

<xsl:variable name="var:vHasValidEndowment" select="count(/*[local-name()='InternalSupport' and namespace-uri()='http://internal_support']/*[local-name()='LoanPartItems' and namespace-uri()='' and isValid ='true'])" />

<xsl:variable name="var:vHasValidId" select="count(/*[local-name()='InternalSupport' and namespace-uri()='http://internal_support']/*[local-name()='Ready' and HasValidId ='true'])" />

<xsl:element name="LeningSoort">

    <xsl:choose>

        <xsl:when test="$var:vAnnuity = $var:vTotalCount">

            <xsl:value-of select="1" />

        </xsl:when>

        <xsl:when test="$var:vLinear = $var:vTotalCount">

            <xsl:value-of select="2" />

        </xsl:when>

        <xsl:when test="($var:vHasValidEndowment = $var:vTotalCount) and ($var:vHasValidId = $var:vTotalCount)">

            <xsl:value-of select="3" />

        </xsl:when>

        <xsl:otherwise>

            <xsl:value-of select="4" />

        </xsl:otherwise>

    </xsl:choose>

</xsl:element>

Of course each specific case requires different XSLT, but this should provide a framework of how to do this within a functoid.

To set up the XSLT:

• Create XSLT similar to the one above which meets your needs
• Drop a scripting functoid on your map
• Connect the output parameter to the node you want to create
• Note: do no include any input parameters, the XSLT is setup already to look them up
• Open the scripting functoid’s, click the (…) inside “Configure Functoid Script”
• Under “Script type” choose “Inline XSLT”
• Paste your XSLT snippet in the text box

XSLT performance when mapping large documents in BizTalk

Recently I had to map a document with many thousand rows. I could not split the document because before I could split it, the document’s nodes had to be sorted.

With such large files you generally test it using a small subset to avoid waiting for maps to complete, I built an XSLT which worked great, I thought.

When you use a select filter such as "not(KeyValue=preceding-sibling::row/ KeyValue)" you end up with a huge performance hit the larger the document gets. My map went from 2 seconds for 50 rows to 10 minutes for a few thousand.

How to improve performance when you have large XML files to map that you can’t split? Try using xsl:key instead, which builds an index of keys from which you can much more efficiently select.

Here is a sample XSLT that demonstrates how to use the xsl:key:

<?xml version="1.0" encoding="UTF-8" ?>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns:ns0="http://Conversion.schemas">

    <xsl:output method="xml" indent="no" />

    <xsl:key name="NumberKey" match="/*[local-name()='top' and namespace-uri()='http://biztalk/Conversion.schemas']/*[local-name()='row' and namespace-uri()='']"

        use="keyValue" />

    <xsl:template match="/">

        <ns0:Rows>

            <xsl:for-each select="/*[local-name()='top' and namespace-uri()='http://biztalk/Conversion.schemas']/*[local-name()='row' and namespace-uri()='' and generate-id(.) = generate-id(key('NumberKey', keyValue)[1])]">

                <xsl:variable name="current_Number" select="keyValue" />

                <Data>

                    <keyValue>

                        <xsl:value-of select="$current_Number" />

                    </keyValue>

                    <xsl:for-each select="//row[keyValue=$current_Number]">

                        <Part>

                            <PartID>

                                <xsl:value-of select="nr_data" />

                            </PartID>

                        </Part>

                    </xsl:for-each>

                </Data>

            </xsl:for-each>

        </ns0:Rows>

    </xsl:template>

</xsl:stylesheet>

You can evaluate dates using the Cumulative Maximum Functoid

Dates you say? Stop the press!

I had a situation where there was a node whose max occurs is unbounded and I needed to extract a single node from it to map to a destination node whose max occurs is one.

The problem was that I had to choose the node to map with the highest (newest) date:
<root>
<data>
<testdate>01-01-2000<testdate>
<testdata>a<testdata>
</data>
<data>
<testdate>01-01-2002<testdate>
<testdata>c<testdata>
</data>
<data>
<testdate>01-01-2001<testdate>
<testdata>b<testdata>
</data>
</root>

In the case above, I want the node with the highest <testval>, or 01-01-2002, therefore I want to map <testdata>c<testdata> to the destination node.

This can actually be done.

What I did was convert my date to ticks in a scripting functoid:

public string toTicks(string param1)
{
DateTime dt = DateTime.Parse(param1);
return dt.Ticks.ToString();
}

Afterwards I connected the scripting functoid to the cumulative max functoid.

Then I evaluate the output of the scripting functoid with the cumulative max functoid with an Equals functoid.

This should work for any set of repeating dates.

BizTalk's mapper allows drag and drop replace

I learned a little trick the other day about the mapper which I have never seen documented. It works for BizTalk 2004 and also 2006.

Have you ever had to change a functoid and gone thru the task of dragging the new functoid onto the grid and then reconnecting all of the lines, then having to check to make sure you got them all in order?

Well, what I realized quite by accident is that you can actually just drag the new functoid over the one you want to replace and all your links will maintain themselves. The old functoid will disappear and be replaced by the new one.

Of course there is a limitation when you have different maximum inputs, etc, but for the most part this works with everything else.