[xsl] How to avoid duplicated items in result tree

[Ramnivas Laddad <ramnivas@xxxxxxx>]

Hello,

I am facing this problem of avoiding duplicate entries in the result tree.
Can somebody please help?

Given XML file such as follows:
<?xml version="1.0"?>
<structure>
    <element name="A_AB">
        <superclass type="A"/>
        <superclass type="A_B"/>
    </element>
    <element name="A_B">
        <superclass type="A"/>
        <superclass type="B"/>
    </element>
    <element name="A"/>
    <element name="B"/>
    <element name="X"/>
</structure>

I want to extract all direct and indirect superclasses of a given element (supplied
as a parameter)

I am trying the following stylesheet:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:output method="xml" indent="yes"/>
<xsl:strip-space elements="*"/>

<xsl:template match="/">
    <elementDetails name = "{$elementToExtract}">
	<xsl:call-template name="printElement">
	    <xsl:with-param name="elementName" select="$elementToExtract"/>
        </xsl:call-template>
    </elementDetails>
</xsl:template>

<xsl:template name="printElement">
    <xsl:param name="elementName"/>

    <xsl:copy-of select="//element[@name=$elementName]"/>

    <xsl:for-each select="//element[@name=$elementName]/superclass">
    	<xsl:call-template name="printElement">
	    <xsl:with-param name="elementName" select="@type"/>	
	</xsl:call-template>
    </xsl:for-each>
</xsl:template>

</xsl:stylesheet>

This stylesheet produced follwing output for element A_AB:
(Command: java org.apache.xalan.xslt.Process -in structure.xml -xsl extract.xsl 
	-param elementToExtract A_AB )

<?xml version="1.0" encoding="UTF-8"?>
<elementDetails name="A_AB">
	<element name="A_AB">
		<superclass type="A"/>
		<superclass type="A_B"/>
	</element>
	<element name="A"/>
	<element name="A_B">
		<superclass type="A"/>
		<superclass type="B"/>
	</element>
	<element name="A"/>  <!-- <<< I will like to avoid this duplicated entry -->
	<element name="B"/>
</elementDetails>

Can somebody suggest me a way to avoid duplicate entries (in above case,
one of the element A) in the result tree.

Thanks.

-Ramnivas

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