Converting a Flat XML to a Nested XML

Question

I'm trying to figure out how to convert a flat xml file to a nested xml file using xslt. Below is an example of the flat xml that I'm trying to transform. I'm using xslt 2 so I can us the grouping commands but I don't know how.

The resulting structure I'm looking for is:

<sources>
 <sourcetype>
   <sourcetypename>Career Fair</sourcetypename>
   <sourcelist>
     <source>
     <sourcename>Ann Arbor News Fair</sourcename>
     <sourceid>CFE-10001</sourceid>
     <eventlist>
       <event>
         <eventname></eventname>
         <eventid></eventid>
       </event>
     </eventlist>
     </source>
   </sourcelist>
</sourcetype>
</sources>

--- Flat XML ----

<?xml version="1.0" encoding="UTF-8"?>
<ExportXML xmlns:ns1="http://www.taleo.com/ws/integration/toolkit/2005/07" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.taleo.com/ws/integration/toolkit/2005/07" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <record>
        <field name="TypeName">Billboards</field>
        <field name="SourceName">Billboard</field>
        <field name="SourceID">BLD-200284</field>
        <field name="EventName"></field>
        <field name="EventID"></field>
        <field name="State">Active</field>
    </record>
    <record>
        <field name="TypeName">Career Fair</field>
        <field name="SourceName">Ann Arbor News Fair</field>
        <field name="SourceID">CFE-10001</field>
        <field name="EventName"></field>
        <field name="EventID"></field>
        <field name="State">Active</field>
    </record>
    <record>
        <field name="TypeName">Career Fair</field>
        <field name="SourceName">Black Data Processing Association (BDPA) </field>
        <field name="SourceID">CFE-10002</field>
        <field name="EventName"></field>
        <field name="EventID"></field>
        <field name="State">Active</field>
    </record>
    <record>
        <field name="TypeName">Career Fair</field>
        <field name="SourceName">Career Concepts</field>
        <field name="SourceID">CFE-10760</field>
        <field name="EventName"></field>
        <field name="EventID"></field>
        <field name="State">Active</field>
    </record>
    </ExportXML>

Answer 1

Nesting a bunch of for-each-group elements starts to look pretty nasty, but it gets the job done:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:t="http://www.taleo.com/ws/integration/toolkit/2005/07">
    <xsl:output omit-xml-declaration="yes" indent="yes"/>
    <xsl:template match="/">
        <sources>
            <xsl:for-each-group select="/*/t:record"
                group-by="t:field[@name='TypeName']">
                <sourcetype>
                    <sourcetypename>
                        <xsl:value-of select="current-grouping-key()"/>
                    </sourcetypename>
                    <sourcelist>
                        <xsl:for-each-group select="current-group()"
                            group-by="t:field[@name='SourceID']">
                            <source>
                                <sourcename>
                                    <xsl:value-of select="t:field[@name='SourceName']"/>
                                </sourcename>
                                <sourceid>
                                    <xsl:value-of select="current-grouping-key()"/>
                                </sourceid>
                                <eventlist>
                                    <xsl:for-each-group
                                        select="current-group()" group-by="t:field[@name='EventID']">
                                        <event>
                                            <eventname>
                                                <xsl:value-of
                                                    select="t:field[@name='EventName']"/>
                                            </eventname>
                                            <eventid>
                                                <xsl:value-of
                                                    select="current-grouping-key()"/>
                                            </eventid>
                                        </event>
                                    </xsl:for-each-group>
                                </eventlist>
                            </source>
                        </xsl:for-each-group>
                    </sourcelist>
                </sourcetype>
            </xsl:for-each-group>
        </sources>
    </xsl:template>
</xsl:stylesheet>

Output:

<sources xmlns:t="http://www.taleo.com/ws/integration/toolkit/2005/07">
   <sourcetype>
      <sourcetypename>Billboards</sourcetypename>
      <sourcelist>
         <source>
            <sourcename>Billboard</sourcename>
            <sourceid>BLD-200284</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
      </sourcelist>
   </sourcetype>
   <sourcetype>
      <sourcetypename>Career Fair</sourcetypename>
      <sourcelist>
         <source>
            <sourcename>Ann Arbor News Fair</sourcename>
            <sourceid>CFE-10001</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
         <source>
            <sourcename>Black Data Processing Association (BDPA) </sourcename>
            <sourceid>CFE-10002</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
         <source>
            <sourcename>Career Concepts</sourcename>
            <sourceid>CFE-10760</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
      </sourcelist>
   </sourcetype>
</sources>

Answer 2

I'm guessing at the final output because I'm not exactly sure what the grouping should be, but here's another 2.0 grouping solution:

XSLT 2.0

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output indent="yes"/>
  <xsl:strip-space elements="*"/>

  <xsl:template match="node()|@*">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="/*:ExportXML">
    <sources>
      <xsl:for-each-group select="*:record" group-by="*:field[@name='TypeName']">
        <xsl:variable name="vType" select="*:field[@name='TypeName']"/>
        <sourcetype>
          <sourcetypename>
            <xsl:apply-templates select="*:field[@name='TypeName']" mode="title"/>
          </sourcetypename>
          <sourcelist>
            <xsl:apply-templates select="/*/*:record[*:field[@name='TypeName'][.=$vType]]"/>
          </sourcelist>
        </sourcetype>
      </xsl:for-each-group>
    </sources>
  </xsl:template>

  <xsl:template match="*:field">
    <xsl:element name="{lower-case(@name)}">
      <xsl:apply-templates/>     
    </xsl:element>
  </xsl:template>

  <xsl:template match="*:record">
    <source>
      <xsl:apply-templates select="*:field[starts-with(@name,'Source')]"/>
      <eventlist>
        <event>
          <xsl:apply-templates select="*:field[starts-with(@name,'Event')]"/>
        </event>
      </eventlist>
    </source>
  </xsl:template>

  <xsl:template match="*:field[@name='TypeName']"/>

  <xsl:template match="*:field[@name='TypeName']" mode="title">
    <xsl:apply-templates/>
  </xsl:template>  

</xsl:stylesheet>

XML output (using supplied XML input and Saxon-HE 9.3)

<sources>
   <sourcetype>
      <sourcetypename>Billboards</sourcetypename>
      <sourcelist>
         <source>
            <sourcename>Billboard</sourcename>
            <sourceid>BLD-200284</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
      </sourcelist>
   </sourcetype>
   <sourcetype>
      <sourcetypename>Career Fair</sourcetypename>
      <sourcelist>
         <source>
            <sourcename>Ann Arbor News Fair</sourcename>
            <sourceid>CFE-10001</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
         <source>
            <sourcename>Black Data Processing Association (BDPA) </sourcename>
            <sourceid>CFE-10002</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
         <source>
            <sourcename>Career Concepts</sourcename>
            <sourceid>CFE-10760</sourceid>
            <eventlist>
               <event>
                  <eventname/>
                  <eventid/>
               </event>
            </eventlist>
         </source>
      </sourcelist>
   </sourcetype>
</sources>