XSLT, how to recognize different pattern during transformation? - xslt

Question

I have a source xml, that looks like below:
<root>
<CompoundPredicate booleanOperator="surrogate">
<CompoundPredicate booleanOperator="and">
<True />
<SimplePredicate field="MODELYEAR" operator="lessOrEqual" value="1999" />
</CompoundPredicate>
<False />
</CompoundPredicate>
<CompoundPredicate booleanOperator="surrogate">
<CompoundPredicate booleanOperator="and">
<True />
<SimplePredicate field="MODELYEAR" operator="lessOrEqual" value="1999" />
</CompoundPredicate>
<SimplePredicate field="AGE" operator="lessOrEqual" value="40" />
<False />
</CompoundPredicate>
</root>
I want to perform a transformation in such way, that
1). if there is only 'False' element after the inner 'CompoundPredicate' element, then delete the outer 'CompoundPredicate' element and the element which appears after the inner 'CompoundPredicate' element. For example,
<CompoundPredicate booleanOperator="surrogate">
<CompoundPredicate booleanOperator="and">
<True />
<SimplePredicate field="MODELYEAR" operator="lessOrEqual" value="1999" />
</CompoundPredicate>
<False />
</CompoundPredicate>
becomes
<CompoundPredicate booleanOperator="and">
<True />
<SimplePredicate field="MODELYEAR" operator="lessOrEqual" value="1999" />
</CompoundPredicate>
2) if there are other elements after the inner 'CompoundPredicate' element other than 'False', then only delete 'False' element which appears after the inner 'CompoundPredicate' element. For example,
<CompoundPredicate booleanOperator="surrogate">
<CompoundPredicate booleanOperator="and">
<True />
<SimplePredicate field="MODELYEAR" operator="lessOrEqual" value="1999" />
</CompoundPredicate>
<SimplePredicate field="AGE" operator="lessOrEqual" value="40" />
<False />
</CompoundPredicate>
becomes
<CompoundPredicate booleanOperator="surrogate">
<CompoundPredicate booleanOperator="and">
<True />
<SimplePredicate field="MODELYEAR" operator="lessOrEqual" value="1999" />
</CompoundPredicate>
<SimplePredicate field="AGE" operator="lessOrEqual" value="40" />
</CompoundPredicate>
For this problem, I don`t even know how to start. I would really appreciate your help. Thanks a lot.

Answer 1

See if this points you in the right direction. It's based on a restatement of your rules, which may or may not be correct:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<!-- identity transform -->
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
<!-- for outer 'CompoundPredicate' that contains only inner 'CompoundPredicate' and/or 'False' -->
<xsl:template match="root/CompoundPredicate[not(*[not(self::CompoundPredicate or self::False)])]">
<xsl:apply-templates select="CompoundPredicate"/>
</xsl:template>
<!-- remove 'False' elements, children of outer 'CompoundPredicate' -->
<xsl:template match="root/CompoundPredicate/False"/>
</xsl:stylesheet>