Can you transform unordered xml to match an xsd:sequence order?

Question

Hi i need to transform unorderd xml using xslt to the correct order as specified in an xsd schema

<Person>
    <property name="address" value="5" />
    <property name="firstname" value="1234567890" />
    <property name="lastname" value="The BFG" />
</Person>

would need to be transformed using

<xs:element name="Person">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="firstname" type="xs:string"/>
            <xs:element name="lastname" type="xs:string"/>
            <xs:element name="address" type="xs:string"/>
        </xs:sequence>
    </xs:complexType>
</xs:element>

The xml could have the properties in any order, with upwars of 10+ property elements.I have tried using an xsl:for-each to try and process the xml but i'm stumped at how to get the xslt to transform the xml into the correct order as defined by the sequence

any help would be appreciated

Answer 1

This may not be the best way, but it seems to work ok. I'm not sure if the order that the xs:element 's are processed is guaranteed though. Also, this is an XSLT 2.0 answer tested with Saxon-HE 9.3.0.5 in oXygen.

XML Input (modified the case of Person to match the schema):

<person>
  <property name="address" value="5" />
  <property name="firstname" value="1234567890" />
  <property name="lastname" value="The BFG" />
</person>

External XSD Schema file (schema.xsd):

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
  <xs:element name="person">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="firstname" type="xs:string"/>
        <xs:element name="lastname" type="xs:string"/>
        <xs:element name="address" type="xs:string"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

XSLT 2.0 Stylesheet:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="#all">
  <xsl:output indent="yes"/>
  <xsl:strip-space elements="*"/>

  <xsl:variable name="input">
    <xsl:copy-of select="/"/>
  </xsl:variable>

  <xsl:template match="/*">
    <xsl:variable name="firstContext" select="name()"/>
    <xsl:variable name="xsdElems" select="document('schema.xsd')/xs:schema/xs:element[@name=$firstContext]/xs:complexType/xs:sequence/xs:element/@name"/>
    <xsl:element name="{$firstContext}">
      <xsl:for-each select="$xsdElems">
        <xsl:variable name="secondContext" select="."/>
        <xsl:element name="{$secondContext}">
          <xsl:value-of select="$input/*/*[@name=$secondContext]/@value"/>
        </xsl:element>
      </xsl:for-each>      
    </xsl:element>
  </xsl:template>

</xsl:stylesheet>

XML Output:

<person>
   <firstname>1234567890</firstname>
   <lastname>The BFG</lastname>
   <address>5</address>
</person>

Hope this helps.

Answer 2

Here is an XSLT 1.0 solution :

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:xs="http://www.w3.org/2001/XMLSchema">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:key name="kxsElemByName" match="xs:element" use="@name"/>

 <xsl:variable name="vSchema" select=
  "document('file:///c:/temp/delete/schema.xsd')"/>

 <xsl:variable name="vDoc" select="/"/>

 <xsl:template match="/*">
  <xsl:variable name="vElem" select="."/>

  <xsl:for-each select="$vSchema">
   <xsl:apply-templates select=
     "key('kxsElemByName', name($vElem))">
    <xsl:with-param name="pElement" select="$vElem"/>
   </xsl:apply-templates>
  </xsl:for-each>
 </xsl:template>

 <xsl:template match="xs:element">
  <xsl:param name="pElement"/>

  <xsl:element name="{name($pElement)}">
   <xsl:apply-templates mode="generate"
        select="xs:complexType/xs:sequence/*">
     <xsl:with-param name="pParent" select="$pElement"/>
   </xsl:apply-templates>
  </xsl:element>
 </xsl:template>

 <xsl:template match="xs:element" mode="generate">
  <xsl:param name="pParent"/>
  <xsl:variable name="vProp" select=
   "$pParent/property[@name = current()/@name]"/>

  <xsl:element name="{$vProp/@name}">
   <xsl:value-of select="$vProp/@value"/>
  </xsl:element>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the provided XML document ( Person renamed to person to match the schema):

<person>
    <property name="address" value="5" />
    <property name="firstname" value="1234567890" />
    <property name="lastname" value="The BFG" />
</person>

and if the provided XML schema is in the file c:\\temp\\delete\\schema.xsd :

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
  <xs:element name="person">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="firstname" type="xs:string"/>
        <xs:element name="lastname" type="xs:string"/>
        <xs:element name="address" type="xs:string"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

then the wanted, correct result is produced :

<person>
   <firstname>1234567890</firstname>
   <lastname>The BFG</lastname>
   <address>5</address>
</person>