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[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Generic Lookup (Element Mapping)
 I have been trying to write a generic xslt template to map the element names based on a lookup table. Is there a reason you want to do this in one stylesheet with both the mapping file and the data file? The lookup xml file has always a subset of the elements and therefore I do not want to hard code the element names. Then you need a customized stylesheet based on your mappings, especially for speed in order to do a single pass on the input data. The output file is a flat xml file in opposite to the input file. This was a particularly difficult criterion to meet. But my main problem is how navigate through the input file in a generic approach. I'm also just a little concern about the overall performance because the input file might be MBs big. For performance reasons, I recommend you write a stylesheet that, based on your mapping, emits a single stylesheet that is then run against your data. This emitted stylesheet does simple matches and should meet your performance requirements. An example of writing a stylesheet that writes a stylesheet is in Chapter 5 of "Definitive XSLT and XPath" which happens to be the freely-downloadable chapter made available by Prentice Hall on the Amazon site. It is also in Chapter 5 of our electronic book from which the paper book was derived. A working answer to your requirements is below. I hope this helps. ...................... Ken
t:\ftemp>type lookup.xml <?xml version="1.0" encoding="iso-8859-1"?> <Maps> <Map> <!-- combination of SEName, SAname and TEname is unique through the file.--> <SEname>aa1</SEname> <!-- element name in the input file--> <SAname>aa11</SAname> <!-- element name in the input file, it's always the child element of SEName--> <TEname>aa_1</TEname> <!-- element name in output--> <TAname>aa_11</TAname> <!-- element nemae in output, it should be the child element of TEname--> </Map> <Map> <SEname>aa1</SEname> <SAname>aa12</SAname> <TEname>aa_1</TEname> <TAname>aa_12</TAname> </Map> <Map> <SEname>aa1</SEname> <SAname>aa13</SAname> <TEname>aa_1A</TEname> <TAname>aa_13</TAname> </Map> <Map> <SEname>aa2</SEname> <SAname>aa21</SAname> <TEname>aa_2</TEname> <TAname>aa_21</TAname> </Map> <!-- no mapping for aa22 --> <Map> <SEname>aa3</SEname> <SAname>aa31</SAname> <TEname>aa_3</TEname> <TAname>aa_31</TAname> </Map> </Maps> t:\ftemp>type faroukh.xsl
<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xslo="junk"
version="1.0"><xsl:namespace-alias stylesheet-prefix="xslo" result-prefix="xsl"/> <xsl:key name="parents" match="Map" use="SEname"/> <xsl:key name="children" match="Map" use="concat(SEname,' ',TEname)"/> <xsl:template match="/">
<xslo:stylesheet version="1.0">
<xslo:output indent="yes"/>
<xslo:template match="/project"><!--preserve project element-->
<project>
<xslo:apply-templates/>
</project>
</xslo:template>
<xslo:template match="*"/><!--throw away unmapped-->
<xslo:template match="text()"/><!--only keep explicitly copied text-->
<xsl:apply-templates/>
</xslo:stylesheet>
</xsl:template><xsl:template match="Map"> <!--only put out a single template for the parent--> <xsl:if test="generate-id(.)=generate-id(key('parents',SEname))"> <xslo:template match="{SEname}"> <!--needs as many apply templates as unique parent mappings--> <xsl:for-each select="key('parents',SEname)[generate-id(.)= generate-id(key('children',concat(SEname,' ',TEname)))]"> <xslo:element name="{TEname}"> <xslo:apply-templates mode="mapping"> <xsl:attribute name="select"> <xsl:for-each select="key('children',concat(SEname,' ',TEname))"> <xsl:if test="position()>1">|</xsl:if> <xsl:value-of select="SAname"/> </xsl:for-each> </xsl:attribute> </xslo:apply-templates> </xslo:element> </xsl:for-each> <xslo:apply-templates/> </xslo:template> </xsl:if> <xslo:template match="{SEname}/{SAname}" mode="mapping"> <xslo:element name="{TAname}"> <xslo:value-of select="."/> </xslo:element> </xslo:template> </xsl:template> </xsl:stylesheet> t:\ftemp>saxon -o mapping.xsl lookup.xml faroukh.xsl t:\ftemp>saxon -o faroukh.out data.xml mapping.xsl t:\ftemp>type faroukh.out
<?xml version="1.0" encoding="utf-8"?>
<project>
<aa_1>
<aa_11>aa11_value</aa_11>
<aa_12>aa12_value</aa_12>
</aa_1>
<aa_1A>
<aa_13>aa13_value</aa_13>
</aa_1A>
<aa_2>
<aa_21>aa21_value</aa_21>
</aa_2>
<aa_3>
<aa_31>aa31_value</aa_31>
</aa_3>
</project>
t:\ftemp>rem Done!
G. Ken Holman mailto:gkholman@xxxxxxxxxxxxxxxxxxxx Crane Softwrights Ltd. http://www.CraneSoftwrights.com/s/ Box 266, Kars, Ontario CANADA K0A-2E0 +1(613)489-0999 (Fax:-0995) ISBN 0-13-065196-6 Definitive XSLT and XPath ISBN 1-894049-08-X Practical Transformation Using XSLT and XPath ISBN 1-894049-07-1 Practical Formatting Using XSLFO XSL/XML/DSSSL/SGML/OmniMark services, books(electronic, printed), articles, training(instructor-live,Internet-live,web/CD,licensed) Next public training: 2002-05-06,07,09,10,13,15,20, - 06-04,07,10,11,13,14,17,20,07-31,08-05,27,30 XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list 
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