How to Duplicate xml elements

Question

i have to duplicate the xml payload into as many xml payloads based on a specific id, e.g., userid

<ns2:Details xmlns:ns2="ns">
  <ns2:var1>AA0511201143</ns2:var1>
  <ns2:var2>PARCEL</ns2:var2>
  <ns2:var3>04/04/2011</ns2:var3>
  <ns2:var4>Organization</ns2:var4>
  <ns2:UserId>46</ns2:UserId>
  <ns2:UserId>237</ns2:UserId>
</ns2:Details>

i need the output as

<ns2:Details>
  <ns2:var1>AA0511201143</ns2:var1>
  <ns2:var2>PARCEL</ns2:var2>
  <ns2:var3>04/04/2011</ns2:var3>
  <ns2:var4>Organization</ns2:var4>
  <ns2:UserId>46</ns2:UserId>
</ns2:Details>
<ns2:Details>
  <ns2:var1>AA0511201143</ns2:var1>
  <ns2:var2>PARCEL</ns2:var2>
  <ns2:var3>04/04/2011</ns2:var3>
  <ns2:var4>Organization</ns2:var4>
  <ns2:UserId>237</ns2:UserId>
</ns2:Details>

is this possible

---

Update: The below answer that was given is working fine, but there's a small catch I failed to mention. If the userid is the same and it's repeating, then the same xml payload should be displayed. For this I tried the following to get the unique elements of userid

<xsl:param name="userId" select="ns0:UserId[generate-id(.)=generate-id(key('k', ns0:UserId)[1])]"/>

but this is not working and also tried using above

..[generate-id(.)=generate-id(key('k', ns0:UserId)[1])] 

at template level also it is not working

Am I missing something?

Update : i made a small modification to the above code, instead of working at xsl:param, i have used it at xsl:apply-template

before modification (provided as answer to me) <xsl:apply-templates select="//ns2:Details/ns2:UserId"/> after modification <xsl:apply-templates select="//ns2:Details/ns2:UserId[generate-id(.)=generate-id(key('myUserId', .)[1])]"/>

my mistake i was using ns2:userid instead of "."

full xsl code ---

<xsl:output method="xml" indent="yes"/>
<xsl:key name="k" match="ns2:UserId" use="text()"/>
<xsl:key name="myUserId" match="ns2:UserId" use="."/>
  <xsl:template match="/">
    <ns2:Root>
            <xsl:apply-templates select="//ns2:Details/ns2:UserId[generate-id(.)=generate-id(key('myUserId', .)[1])]"/>
    </ns2:Root>
  </xsl:template>

<xsl:template match="//ns2:Details">
    <xsl:param name="userId" select="ns2:UserId"/>
    <ns2:Details>
      <xsl:copy-of select="key('k', $userId)[1]"/>  <!-- displays UserId values-->
      <xsl:copy-of select="./*[name() != 'ns2:UserId']"/> <!-- displays other values-->
    </ns2:Details>
  </xsl:template>

<xsl:template match="ns2:UserId">
    <xsl:apply-templates select="..">
      <xsl:with-param name="userId" select="."/>
    </xsl:apply-templates>
  </xsl:template>

Please, validate it. this too is working for me...

Answer 1

Supposed XML:

<ns2:Details xmlns:ns2="ns2">
  <ns2:var1>AA0511201143</ns2:var1>
  <ns2:var2>PARCEL</ns2:var2>
  <ns2:var3>04/04/2011</ns2:var3>
  <ns2:var4>Organization</ns2:var4>
  <ns2:UserId>46</ns2:UserId>
  <ns2:UserId>237</ns2:UserId>
  <ns2:UserId>46</ns2:UserId>
</ns2:Details>

XSLT:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:ns2="ns2"
>
  <xsl:output method="xml" indent="yes"/>

  <xsl:key name="k" match="ns2:UserId" use="text()"/>

  <xsl:template match="/">
    <root>
      <xsl:apply-templates select="//ns2:Details/ns2:UserId[not(node() = preceding-sibling::node())]"/>
    </root>
  </xsl:template>

  <xsl:template match="//ns2:Details">
    <xsl:param name="userId" select="ns2:UserId"/>

    <ns2:Details>
      <xsl:copy-of select="key('k', $userId)[not(node() = preceding-sibling::node())]"/>
      <xsl:copy-of select="./*[name() != 'ns2:UserId']"/>
    </ns2:Details>
  </xsl:template>

  <xsl:template match="ns2:UserId">
    <xsl:apply-templates select="..">
      <xsl:with-param name="userId" select="."/>
    </xsl:apply-templates>
  </xsl:template>

</xsl:stylesheet>

Output XML:

<?xml version="1.0" encoding="utf-8"?>
<root xmlns:ns2="ns2">
  <ns2:Details>
    <ns2:UserId>46</ns2:UserId>
    <ns2:var1>AA0511201143</ns2:var1>
    <ns2:var2>PARCEL</ns2:var2>
    <ns2:var3>04/04/2011</ns2:var3>
    <ns2:var4>Organization</ns2:var4>
  </ns2:Details>
  <ns2:Details>
    <ns2:UserId>237</ns2:UserId>
    <ns2:var1>AA0511201143</ns2:var1>
    <ns2:var2>PARCEL</ns2:var2>
    <ns2:var3>04/04/2011</ns2:var3>
    <ns2:var4>Organization</ns2:var4>
  </ns2:Details>
</root>

Answer 2

This transformation (short, only two templates, no xsl:for-each, no modes):

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ns2="ns">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:key name="kIdByVal" match="ns2:UserId" use="."/>

 <xsl:template match="/">
  <xsl:apply-templates select=
  "ns2:Details/ns2:UserId
        [generate-id()=generate-id(key('kIdByVal',.)[1])]
  "/>
 </xsl:template>

 <xsl:template match="ns2:UserId">
  <ns2:Details>
   <xsl:copy-of select=
    "../node()
          [not(self::ns2:UserId
                 [not(generate-id()=generate-id(current()))])
          ]"/>
  </ns2:Details>
 </xsl:template>
</xsl:stylesheet>

when applied on this XML document (containing redundant ns2:UserId elements):

<ns2:Details xmlns:ns2="ns">
    <ns2:var1>AA0511201143</ns2:var1>
    <ns2:var2>PARCEL</ns2:var2>
    <ns2:var3>04/04/2011</ns2:var3>
    <ns2:var4>Organization</ns2:var4>
    <ns2:UserId>46</ns2:UserId>
    <ns2:UserId>237</ns2:UserId>
    <ns2:UserId>46</ns2:UserId>
</ns2:Details>

produces exactly the wanted, correct result:

<ns2:Details xmlns:ns2="ns">
   <ns2:var1>AA0511201143</ns2:var1>
   <ns2:var2>PARCEL</ns2:var2>
   <ns2:var3>04/04/2011</ns2:var3>
   <ns2:var4>Organization</ns2:var4>
   <ns2:UserId>46</ns2:UserId>
</ns2:Details>
<ns2:Details xmlns:ns2="ns">
   <ns2:var1>AA0511201143</ns2:var1>
   <ns2:var2>PARCEL</ns2:var2>
   <ns2:var3>04/04/2011</ns2:var3>
   <ns2:var4>Organization</ns2:var4>
   <ns2:UserId>237</ns2:UserId>
</ns2:Details>

Explanation: Muenchian grouping, xsl:copy-of, use of current()