Selectively copy and update xml nodes using XSLT

Question

I'm working with an xml that I need to copy and update to pass on for further processing. The issue I'm having is that I have not figured out an efficient method to do this. Essentially, I want to update some data, conditionally, then copy all the nodes that were not updated. Why this is challenging is due to the volume and variance in the number and name of nodes to be copied. I also want to NOT copy nodes that have no text value. Here is an example:

INPUT XML

  <root>
     <PersonProfile xmlns:'namespace'>
        <ID>0001</ID>
        <Name>
           <FirstName>Jonathan</FirstName>
           <PreferredName>John</PreferredName>
           <MiddleName>A</MiddleName>
           <LastName>Doe</LastName>
        </Name>
        <Country>US</Country>
        <Biirthdate>01-01-1980</Birthdate>
        <BirthPlace>
           <City>Townsville</City>
           <State>OR</State>
           <Country>US</Country>
        </Birthplace>
        <Gender>Male</Gender>
        <HomeState>OR</HomeState>
        ...
        <nodeN>text</nodeN>
     </PersonProfile>
 </root>

The "PersonProfile" node is just one of several node sets within the "root" element, each with their own subset of data. Such as mailing address, emergency contact info, etc. What I am attempting to do is update nodes if the variable has a new value for them then copy all the nodes that were not updated.

Here is my current XSLT

 <xsl:stylesheet version="2.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

 <xsl:variable name='updateData' select='document("report")'/>

 <!-- Identity Transform -->
 <xsl:template match='@* | node()'>
     <xsl:if test'. != ""'>
        <xsl:copy>
            <xsl:apply-templates select='@* | node()'/>
        </xsl:copy>
      </xsl:if>
  </xsl:template>

 <!-- Template to update Person Profile -->
  <xsl:template match='PersonProfile'>   
    <xsl:copy>
        <xsl:apply-templates select='*'/>    
        <xsl:element name='Name'>
            <xsl:if test='exists($updateData/Preferred)'>
               <xsl:element name='FirstName'>
                  <xsl:value-of select='$reportData/FirstName'/>
               </xsl:element>
            </xsl:if>            
            <xsl:if test='exists($updateData/Preferred)'>
               <xsl:element name='PreferredName'>
                   <xsl:value-of select='$updateData/Preferred'/>
               </xsl:element>
            </xsl:if>
            <xsl:if test='exists($updateData/Middle)'>
            <xsl:element name='MiddleName'>
                <xsl:value-of select='$updateData/Middle'/>
            </xsl:element>
            </xsl:if>
            <xsl:if test='exists($updateData/LastName)'>
               <xsl:element name='LastName'>
                   <xsl:value-of select='$updateData/wd:LastName'/>
               </xsl:element>
            </xsl:if> 
         </xsl:element>
         <xsl:if test='exists($updateData/Country)'>
            <xsl:element name='Country'>
               <xsl:value-of select='$updateData/Country'/>
            </xsl:element>
         </xsl:if> 
         ....
         <!-- follows same structure until end of template -->
    </xsl:copy>
  </xsl:template>

 <!-- More Templates to Update other Node sets -->

</xsl:stylesheet>

What's happening right now, is that it's copying ALL the nodes and then adding the updates values. Using Saxon-PE 9.3.0.5, I'll get an output similar to this:

Sample Output

  <root>
     <PersonProfile xmlns:'namespace'>
        <ID>0001</ID>
        <Name>
           <FirstName>Jonathan</FirstName>
           <PreferredName>John</PreferredName>
           <MiddleName>A</MiddleName>
           <LastName>Doe</LastName>
        </Name>
        <Country>US</Country>
        <Biirthdate>01-01-1980</Birthdate>
        <BirthPlace>
           <City>Townsville</City>
           <State>OR</State>
           <Country>US</Country>
        </Birthplace>
        <Gender>Male</Gender>
        <HomeState>OR</HomeState>
        ...
        <nodeN>text</nodeN>
        <PreferredName>Jonathan</PreferredName>
        <HomeState>WA</HomeState>
     </PersonProfile>
 </root>

I realize this is happening because I am applying the templates to all the nodes in PersonProfile and that I could specify which nodes to exclude, but I feel like this is a very poor solution as the volume of nodes could be upwards of 30 or more and that would require a written value for each one. I trust XML has a more elegant solution than to explicitly list each of these nodes. I would like to have an out like this:

Desired Output

  <root>
     <PersonProfile xmlns:'namespace'>
        <ID>0001</ID>
        <Name>
           <FirstName>Jonathan</FirstName>
           <PreferredName>Jonathan</PreferredName>
           <MiddleName>A</MiddleName>
           <LastName>Doe</LastName>
        </Name>
        <Country>US</Country>
        <Biirthdate>01-01-1980</Birthdate>
        <BirthPlace>
           <City>Townsville</City>
           <State>OR</State>
           <Country>US</Country>
        </Birthplace>
        <Gender>Male</Gender>
        <HomeState>WA</HomeState>
        ...
        <nodeN>text</nodeN>
     </PersonProfile>
 </root>

If anyone could help me create a template structure that would work for the xml structure, I would GREATLY appreciate it. It would need to be "reusable" as there are similar node structures like Person Profile I would have to apply it to, but with different node names and number of elements, etc.

Thanks in advance for any help!

• J

Answer 1

This should work for your original question:

<xsl:stylesheet version="2.0" 
                xmlns:xs="http://www.w3.org/2001/XMLSchema" 
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

  <xsl:variable name='updateData' select='document("report")'/>

  <!-- Identity Transform -->
  <xsl:template match='@* | node()' name='copy'>
      <xsl:copy>
        <xsl:apply-templates select='@* | node()'/>
      </xsl:copy>
  </xsl:template>

  <xsl:template match='*[not(*)]'>
    <xsl:variable name='matchingValue' 
                  select='$updateData/*[name() = name(current())]'/>
    <xsl:choose>
      <xsl:when test='$matchingValue'>
        <xsl:copy>
          <xsl:apply-templates select='@*' />
          <xsl:value-of select='$matchingValue'/>
        </xsl:copy>
      </xsl:when>
      <xsl:when test='normalize-space()'>
        <xsl:call-template name='copy' />
      </xsl:when>
    </xsl:choose>
  </xsl:template>
</xsl:stylesheet>

As far as inserting new elements that are not present in the source XML, that's trickier. Could you open a separate question for that? I may have some ideas for how to approach that.