How to group at more than one level? - xslt

Question

I have an XML file:
<document>
<line id="0">
<field id="2">X111</field>
<field id="3">1</field>
<field id="4">222222222222</field>
</line>
<line id="1">
<field id="2">X111</field>
<field id="3">1</field>
<field id="4">111111111111</field>
</line>
<line id="2">
<field id="2">X222</field>
<field id="3">1</field>
<field id="4">111111111111</field>
</line>
<line id="3">
<field id="2">X222</field>
<field id="3">1></field>
<field id="4">111111111111</field>
</line>
<line id="4">
<field id="2">X333</field>
<field id="3">1</field>
<field id="4">111111111111</field>
</line>
</document>
From this xml file I should group field2 (after that field4 ), question will be not to how to group field 2 and get three documents but how to group field4 if they are the same?
Output:
<document>
<Result>
<Header>
<Field2>X111</Field2>
</Header>
<Line>
<Position>1</Position>
<Field4>222222222222</Field4>
<Sum>1<Sum>
<Position>2</Position>
<Field4>111111111111</Field4>
<Sum>1<Sum>
</Line>
</Result>
<Result>
<Header>
<Field2>X222</Field2>
</Header>
<Line>
<Position>1</Position>
<Field4>111111111111</Field4>
<Sum>2<Sum>
</Line>
</Result>
<Result>
<Header>
<Field2>X333</Field2>
</Header>
<Line>
<Position>1</Position>
<Field4>111111111111</Field4>
<Sum>1</Sum>
</Line>
</Result>
</document>
I'm stuck in grouping lines, I didn't know how to group the same and different fields which id= 4.
My program looks:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:key name="kLine" match="line" use="string(field[#id=2])"/>
<xsl:key name="bLine" match="line" use="field[#id=4]"/>
<xsl:template match="document">
<document>
<xsl:apply-templates select="line[count( . | key('kLine', string(field[#id='2']))[1]) = 1]"/>
</document>
</xsl:template>
<xsl:template match="line">
<xsl:variable name="field2" select="field[#id='2']"/>
<result>
<Header>
<xsl:value-of select="field[#id='2']"/>
</Header>
<Line>
<xsl:for-each select="//line[field[#id='2']=$field2]">
<Position>
<xsl:value-of select="position()"/>
</Position>
<Field4><xsl:value-of select="field[#id='4']"/></Field4>
<Sum><xsl:value-of select="sum(key('bLine', field[#id='4'])/field[#id='3'])"/></Sum>
</xsl:for-each>
</Line>
</result>
</xsl:template>
</xsl:stylesheet>

Answer 1

You're asking how to group at multiple levels. The following stylesheet:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:key name="byField2" match="line" use="field[#id='2']" />
<xsl:key name="byField2AndField4" match="line"
use="concat(field[#id='2'], '|', field[#id='4'])" />
<xsl:template match="/">
<document><xsl:apply-templates /></document>
</xsl:template>
<xsl:template
match="line[generate-id() =
generate-id(key('byField2', field[#id='2'])[1])]">
<Result>
<Header>
<Field2><xsl:value-of select="field[#id='2']" /></Field2>
</Header>
<Line>
<xsl:apply-templates
select="key('byField2', field[#id='2'])
[generate-id() =
generate-id(key('byField2AndField4',
concat(field[#id='2'], '|', field[#id='4']))[1])]"
mode="field4" />
</Line>
</Result>
</xsl:template>
<xsl:template match="line" mode="field4">
<Position><xsl:value-of select="position()" /></Position>
<Field4><xsl:value-of select="field[#id='4']" /></Field4>
<Sum>
<xsl:value-of
select="sum(key('byField2AndField4',
concat(field[#id='2'], '|', field[#id='4']))/
field[#id='3'])" />
</Sum>
</xsl:template>
<xsl:template match="line" />
</xsl:stylesheet>
On this input:
<document>
<line id="0">
<field id="2">X111</field>
<field id="3">1</field>
<field id="4">222222222222</field>
</line>
<line id="1">
<field id="2">X111</field>
<field id="3">1</field>
<field id="4">111111111111</field>
</line>
<line id="2">
<field id="2">X222</field>
<field id="3">1</field>
<field id="4">111111111111</field>
</line>
<line id="3">
<field id="2">X222</field>
<field id="3">1></field>
<field id="4">111111111111</field>
</line>
<line id="4">
<field id="2">X333</field>
<field id="3">1</field>
<field id="4">111111111111</field>
</line>
</document>
Produces the desired result:
<document>
<Result>
<Header>
<Field2>X111</Field2>
</Header>
<Line>
<Position>1</Position>
<Field4>222222222222</Field4>
<Sum>1</Sum>
<Position>2</Position>
<Field4>111111111111</Field4>
<Sum>1</Sum>
</Line>
</Result>
<Result>
<Header>
<Field2>X222</Field2>
</Header>
<Line>
<Position>1</Position>
<Field4>111111111111</Field4>
<Sum>2</Sum>
</Line>
</Result>
<Result>
<Header>
<Field2>X333</Field2>
</Header>
<Line>
<Position>1</Position>
<Field4>111111111111</Field4>
<Sum>1</Sum>
</Line>
</Result>
</document>
We use two keys. The first groups only by field 2. The second groups by the concatenation of fields 2 and 4.