Question

I am using XSLT for converting a XML derived from web and convert the same on the fly into the target xml file denoted as output .
I am still unable to do so even after trying a lot , Can anyone please help me out with this conversion .

Source XML

<allocelement>
    <hd1>12</hd1>
    <hd2>14</hd2>
    <hd3>87</hd3>
        <alc>1</alc>
    <amount>4587</amount>
    <code>1111</code>
</allocelement>
<alloclement>
        <hd1>12</hd1>
    <hd2>14</hd2>
    <hd3>87</hd3>
    <alc>2</alc>
    <amount>80000</amount>
    <code>1111</code>
</alloclement>
<alloclement>
    <hd1>875</hd1>
    <hd2>455</hd2>
    <hd3>455</hd3>
    <alc>2</alc>
    <amount>80000</amount>
    <code>1112</code>
 </alloclement>

Output Desired

<allocelement>
    <Codeheader>
    <code>1111</code>
        <hd1>12</hd1>
        <hd2>14</hd2>
        <hd3>87</hd3>
                <alc>1</alc>
                    <amount>4587</amount>
                <alc>2</alc>
                    <amount>80000</amount>
    </codeHeader>
        <CodeHeader>
    <code>1112</code>
        <hd1>875</hd1>
        <hd2>455</hd2>
        <hd3>455</hd3>
            <alc>2</alc>
              <amount>80000</amount>
    </CodeHeader>
</allocelement>

The Grouping is on the basis of Code,[hd1,hd2,hd3] such that the different elements within which have the same Code and [hd1,hd2,hd3] will be merged and only show fields which are different viz. the and .
Also I am using xslt 1.0 .

Answer 1

A significantly shorter and simpler XSLT 1.0 solution:

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

 <xsl:key name="kCodeByVal" match="code" use="."/>

 <xsl:template match="/*">
  <allocelement>
   <xsl:apply-templates/>
  </allocelement>
 </xsl:template>

<xsl:template match="allocelement"/>

 <xsl:template match=
  "allocelement
    [generate-id(code) = generate-id(key('kCodeByVal', code)[1])]">
  <code><xsl:value-of select="code"/>
    <xsl:copy-of select=
    "node()[not(self::code)]
    | key('kCodeByVal', code)/../*[self::alc or self::amount]"/>
  </code>
 </xsl:template>
</xsl:stylesheet>

When this transformation is applied on the following XML document (a single top element wrapping the provided XML fragment):

<t>
    <allocelement>
        <hd1>12</hd1>
        <hd2>14</hd2>
        <hd3>87</hd3>
        <alc>1</alc>
        <amount>4587</amount>
        <code>1111</code>
    </allocelement>
    <allocelement>
        <hd1>12</hd1>
        <hd2>14</hd2>
        <hd3>87</hd3>
        <alc>2</alc>
        <amount>80000</amount>
        <code>1111</code>
    </allocelement>
    <allocelement>
        <hd1>875</hd1>
        <hd2>455</hd2>
        <hd3>455</hd3>
        <alc>2</alc>
        <amount>80000</amount>
        <code>1112</code>
    </allocelement>
</t>

the wanted, correct result is produced:

<allocelement>
   <code>1111<hd1>12</hd1>
      <hd2>14</hd2>
      <hd3>87</hd3>
      <alc>1</alc>
      <amount>4587</amount>
      <alc>2</alc>
      <amount>80000</amount>
   </code>
   <code>1112<hd1>875</hd1>
      <hd2>455</hd2>
      <hd3>455</hd3>
      <alc>2</alc>
      <amount>80000</amount>
   </code>
</allocelement>

Explanation: Proper use of the Muenchian grouping method.

---

II. XSLT 2.0 solution — again shorter, and much more importantly — syntactically and semantically correct:

<xsl:stylesheet version="2.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

  <xsl:template match="/*">
  <allocelement>
   <xsl:for-each-group select="*" group-by="code">
     <code><xsl:value-of select="code"/>
        <xsl:sequence select=
        "node()[not(self::code)]
        | current-group()/*[self::alc or self::amount]"/>
  </code>
   </xsl:for-each-group>
  </allocelement>
 </xsl:template>
</xsl:stylesheet>

UPDATE: The OP has changed the requirements for the outpu.

Here is the corresponding modified XSLT 1.0 solution:

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

     <xsl:key name="kCodeByVal" match="code" use="."/>

     <xsl:template match="/*">
      <allocelement>
       <xsl:apply-templates/>
      </allocelement>
     </xsl:template>

    <xsl:template match="allocelement"/>

     <xsl:template match=
      "allocelement
        [generate-id(code) = generate-id(key('kCodeByVal', code)[1])]">
      <codeHeader>
       <code><xsl:value-of select="code"/></code>
         <xsl:copy-of select=
         "node()[not(self::code)]
         | key('kCodeByVal', code)/../*[self::alc or self::amount]"/>
      </codeHeader>
     </xsl:template>
</xsl:stylesheet>