Re: [xsl] merging multiple xml files

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 2003-06-04 14:36 -0500, RPeterson@xxxxxxxxxxxxxx wrote:
> I have multiple xml files that I wish to merge. An example of the files is
> below.  Note that a file
> may contain thousands of <detail> nodes.

Having chosen to use XSLT, all these nodes will need to be in memory in 
source node trees.

> I have been using a master xml file to try and merge but with no success in
> keeping the clients together.

This is a grouping issue, and grouping across separate source files is very 
straightforward when using the variable-based grouping method.  A working 
result is below (modulo how you want to handle the whitespace when 
indenting ... I advise that after confirming this is what you want to 
happen that you remove the <xsl:output> instruction because of the 
arbitrary indenting).

You'll see that it isn't very long at all.

> Also, due to the size of the files, is using xsl:copy and xsl:copy-of the
> best way to approach this.

"Best" in what sense?  Any choice here will not impact on your memory 
capacity issues regarding storing the source node trees ... it is in the 
architecture of XSLT (much like with DOM) that the entire source node tree 
of any source file be loaded in memory before any node of that tree is 
accessed ... and there are no guidelines for garbage collection and freeing 
memory.

I hope this helps.

................ Ken


T:\ftemp>type peterson.xml
<masterfile>
      <doc filename="file1.xml"/>
      <doc filename="file2.xml"/>
      <doc filename="file3.xml"/>
</masterfile>

T:\ftemp>type file1.xml
<client>
      <name>A</name>
      <subclient>
            <name>a</name>
            <detail>....</detail>
            <detail>....</detail>
      </subclient>
</client>

T:\ftemp>type file2.xml
<client>
      <name>A</name>
      <subclient>
            <name>b</name>
            <detail>....</detail>
            <detail>....</detail>
      </subclient>
</client>

T:\ftemp>type file3.xml
<client>
      <name>B</name>
      <subclient>
            <name>c</name>
            <detail>....</detail>
            <detail>....</detail>
      </subclient>
</client>

T:\ftemp>type peterson.xsl
<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                version="1.0">

<xsl:output indent="yes"/>

<xsl:template match="masterfile">
  <merged>
    <xsl:variable name="clients" select="document(doc/@filename)/client"/>

    <xsl:for-each select="$clients">
      <xsl:if test="generate-id(.)=
                    generate-id($clients[name=current()/name])">
        <client>
          <xsl:copy-of select="name"/>
          <xsl:copy-of select="$clients[name=current()/name]/subclient"/>
        </client>
      </xsl:if>
    </xsl:for-each>
  </merged>
</xsl:template>

</xsl:stylesheet>

T:\ftemp>saxon -o peterson.out peterson.xml peterson.xsl

T:\ftemp>type peterson.out
<?xml version="1.0" encoding="utf-8"?>
<merged>
   <client>
      <name>A</name>
      <subclient>

         <name>a</name>

         <detail>....</detail>

         <detail>....</detail>

      </subclient>
      <subclient>

         <name>b</name>

         <detail>....</detail>

         <detail>....</detail>

      </subclient>
   </client>
   <client>
      <name>B</name>
      <subclient>

         <name>c</name>

         <detail>....</detail>

         <detail>....</detail>

      </subclient>
   </client>
</merged>


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G. Ken Holman                mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
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