XSL modify output based on presence of element data in another file - xslt

Question

This is all new to me and I'm trying to learn how it works by examining and modifying some pre-existing XSL on our system, so please excuse that I don't really have a test script to troubleshoot.
I have an exported list of rooms that exist on our system - and a survey of criteria within those rooms.
I want to lookup the surveyed room and alter the behaviour of the output depending on whether it exists on the export or not.
Some sample data below which gives an idea of what I want to achieve. I'm just not sure how to (a) link to the reference xml and (b) query it in this way.
Reference listing XML (name = spaces.xml):
<Listing>
<Space>
<Code>Room1</Code>
</Space>
<Space>
<Code>Room2</Code>
</Space>
<Space>
<Code>Room3</Code>
</Space>
<Space>
<Code>Room4</Code>
</Space>
</Listing>
Survey XML example
<Survey>
<Record>
<Ref>1</Ref>
<Space>Room1</Space>
<Data>123</Data>
</Record>
<Record>
<Ref>2</Ref>
<Space>Room2</Space>
<Data>456</Data>
</Record>
<Record>
<Ref>3</Ref>
<Space>Room5</Space>
<Data>789</Data>
</Record>
</Survey>
As room 5 is not in the listing, the output should behave differently
XSLT so far. This doesn't include the reference to the listing.xml file or the proper test condition
xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:output method="xml"/>
<xsl:template match="Record">
<OutputData>
<SurveyRef>
<xsl:value-of select="Ref"/>
</SurveyRef>
<xsl:choose>
<xsl:when test="##SPACE IS PRESENT IN SPACES.XML##">
<SpaceRef>
<xsl:value-of select="Space"/>
</SpaceRef>
<xsl:otherwise>
<SpaceRef>CheckTheSpace</SpaceRef>
</xsl:otherwise>
</xsl:choose>
<SurveyResult>
<xsl:value-of select="Data"/>
</SurveyResult>
</OutputData>
</xsl:template>
</xsl:stylesheet>
Hoped-for output
<OutputData>
<SurveyRef>1</SurveyRef>
<SpaceRef>Room1</SpaceRef>
<SurveyResult>123</SurveyResult>
</OutputData>
<OutputData>
<SurveyRef>2</SurveyRef>
<SpaceRef>Room2</SpaceRef>
<SurveyResult>456</SurveyResult>
</OutputData>
<OutputData>
<SurveyRef>3</SurveyRef>
<SpaceRef>CheckTheSpace</SpaceRef>
<SurveyResult>789</SurveyResult>
</OutputData>
Any help with this much appreciated, as I'm sure it will help me get to use this tool more
effectively.
Thanks.

Answer 1

how to (a) link to the reference xml
It depends on where exactly the reference document will be. If you place it at the same location where your XSLT stylesheet is, then you can refer to it using just its name within the document() function. Otherwise you need to use either a relative or a full absolute path.
and (b) query it in this way.
The most convenient way to resolve a cross-reference is by using a key - for example:
XSLT 2.0
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:key name="spc" match="Space" use="Code" />
<xsl:template match="/Survey">
<root>
<xsl:for-each select="Record">
<OutputData>
<SurveyRef>
<xsl:value-of select="Ref"/>
</SurveyRef>
<SpaceRef>
<xsl:value-of select="if (key('spc', Space, document('space.xml'))) then Space else 'CheckTheSpace'"/>
</SpaceRef>
<SurveyResult>
<xsl:value-of select="Data"/>
</SurveyResult>
</OutputData>
</xsl:for-each>
</root>
</xsl:template>
</xsl:stylesheet>