Advice on how to replace call-template with apply-templaes (if possible)

apollo13 · August 10th, 2012, 03:35 AM

Hi,

I currently have a xml file like this:

Code:

<?xml version="1.0" encoding="UTF-8"?>
<data>
  <config>
    <field1 sort="group">field1</field1>
    <field2 sort="group">field2</field2>
    <field3>field3</field3>
    <field4>field4</field4>
  </config>
  <rows>
    <row>
      <field1>c</field1>
      <field2>g</field2>
      <field3>c</field3>
      <field4>test2</field4>
    </row>
    <row>
      <field1>a</field1>
      <field2>b</field2>
      <field3>z</field3>
      <field4>test</field4>
    </row>
    <row>
      <field1>a</field1>
      <field2>b</field2>
      <field3>a</field3>
      <field4>test2</field4>
    </row>
  </rows>
</data>

Now what I want to to is to generate a HTML table which is grouped according to the config-element, eg grouped by field1,field2 and then field3 and field4 ungrouped (as specified in the config).

My current (working) approach is this:

Code:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">

  <xsl:output method="html" indent="yes" version="5.0"/>

  <xsl:template match="data">
    <html>
    <body>
      <table border="1">
        <thead>
          <tr>
            <xsl:for-each select="config/*">
              <th><xsl:value-of select="."/></th>
            </xsl:for-each>
          </tr>
        </thead>
        <tbody>
          <xsl:call-template name="table-helper">
            <xsl:with-param name="config" select="config"/>
          </xsl:call-template>
        </tbody>
      </table>
    </body>
    </html>
  </xsl:template>

  <xsl:template name="table-helper">
    <xsl:param name="config" required="yes"/>
    <xsl:param name="column" select="1" as="xs:integer"/>
    <xsl:param name="first-round" select="xs:boolean(1)" as="xs:boolean"/>

    <xsl:variable name="current-column" select="$config/*[$column]"/>
    <xsl:variable name="current-data" select="if($first-round) then rows/row else current-group()"/>

    <xsl:choose>

      <xsl:when test="$current-column/@sort = 'group'">
        <xsl:for-each-group select="$current-data"
                            group-by="*[local-name() = $current-column/local-name()]">
          <xsl:call-template name="table-helper">
            <xsl:with-param name="first-round" select="xs:boolean(0)"/>
            <xsl:with-param name="column" select="$column + 1"/>
            <xsl:with-param name="config" select="$config"/>
          </xsl:call-template>
        </xsl:for-each-group>
      </xsl:when>

      <xsl:otherwise>
        <xsl:for-each select="$current-data">
          <tr>
            <xsl:for-each select="for $i in $config/* return *[local-name() = $i/local-name()]">
              <td><xsl:value-of select="."/></td>
            </xsl:for-each>
          </tr>
        </xsl:for-each>
      </xsl:otherwise>

    </xsl:choose>
  </xsl:template>

</xsl:stylesheet>

Now while this works I am wondering if I can rewrite that to apply-templates and if rewriting makes sense at all. (Also: If there are any non-xsl-isms in the template please tell me)

Thx,
Florian

samjudson · August 10th, 2012, 05:36 AM

I'll be honest I can't see what your call-template is actually meant to do.

Running it against the sample XML it simply prints out the rows, one after the other. Any attempt to 'group' (which from the wording it appears to be trying to do) seems to fail.

As for re-writing - generally in XSLT I tend to favour trying to use template matching, as this is kind of the way XSLT is 'meant' to be used (and I use 'meant' in the very loosest sense). So you might certainly benefit your knowledge of XSLT by rewriting. It might also be easier to maintain perhaps.

apollo13 · August 10th, 2012, 05:41 AM

Quote:

Originally Posted by samjudson

Running it against the sample XML it simply prints out the rows, one after the other. Any attempt to 'group' (which from the wording it appears to be trying to do) seems to fail.

Oh it does group, but yes currently every row displays the full data (for now). Granted the example xml isn't the best, but take this one:

Code:

<?xml version="1.0" encoding="UTF-8"?>
<data>
  <config>
    <field1 sort="group">field1</field1>
    <field2 sort="group">field2</field2>
    <field3>field3</field3>
    <field4>field4</field4>
  </config>
  <rows>
    <row>
      <field1>a</field1>
      <field2>b</field2>
      <field3>z</field3>
      <field4>test</field4>
    </row>
    <row>
      <field1>c</field1>
      <field2>g</field2>
      <field3>c</field3>
      <field4>test2</field4>
    </row>
    <row>
      <field1>a</field1>
      <field2>b</field2>
      <field3>a</field3>
      <field4>test2</field4>
    </row>
  </rows>

Using the above xml example you will see the first two rows in the output have field1=a, which means they have been grouped since the row with field1=c went down to the bottom. I hope that clears it up for you.

Quote:

As for re-writing - generally in XSLT I tend to favour trying to use template matching, as this is kind of the way XSLT is 'meant' to be used (and I use 'meant' in the very loosest sense). So you might certainly benefit your knowledge of XSLT by rewriting. It might also be easier to maintain perhaps.

Yes, but I don't know how to achieve the same result using matching, that's my issue…