Merge different products belong to each standard

Question

I have to transform the following xml content,

    
        200057<         


        

Answer 1

Switching from imperative "pull" processing (<xsl:for-each...>) to "push" processing, where you depend on the natural processing loop of the XSL engine, simplifies the stylesheet significantly.

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:x="http://ws.wso2.org/dataservice"
    xmlns="http://ws.wso2.org/dataservice"
    exclude-result-prefixes="x"
    version="1.0">

    <xsl:output indent="yes" method="xml" />

    <!-- Identity Transform -->
    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>

    <xsl:template match="x:Standard">
        <xsl:copy>
            <xsl:copy-of select="x:ProductID"/>
            <xsl:copy-of select="x:Prefix"/>
            <xsl:copy-of select="x:SNumber"/>
            <RelatedProducts>
                <xsl:apply-templates select=".//x:RelatedProduct"/>
            </RelatedProducts>
            <xsl:copy-of select="x:S1"/>
            <xsl:copy-of select="x:S2"/>
        </xsl:copy>
    </xsl:template>

    <xsl:template match="x:RelatedProduct">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
            <RelationType><xsl:value-of select="name(..)"/></RelationType>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>

This is essentially an "identity transform" plus one template to match Standard, and output only what we want from within it. The template for x:RelatedProduct copies those elements to the output verbatim and adds the RelationType element whose text is the name of the containing element.

Output is

<?xml version="1.0" encoding="UTF-8"?>
<Standards xmlns="http://ws.wso2.org/dataservice">
    <Standard>
      <ProductID>200057</ProductID>
      <Prefix>ISO</Prefix>
      <SNumber>1001</SNumber>
      <RelatedProducts>
         <RelatedProduct>
                <ProductID>1500163</ProductID>
            <RelationType>DraftProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID>263973</ProductID>
                <RelationId>708519</RelationId>
                <Designation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
            <RelationType>ReferenceProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID>320056</ProductID>
                <RelationId>934789</RelationId>
                <Designation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
            <RelationType>ReferenceProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
                <RelationId>116881</RelationId>
                <Relationship>Identical</Relationship>
                <Designation>NEN ISO 1001</Designation>
            <RelationType>RelatedIntProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID>208076</ProductID>
                <RelationId>116886</RelationId>
                <Relationship>Identical</Relationship>
                <Designation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
            <RelationType>RelatedIntProducts</RelationType>
         </RelatedProduct>
      </RelatedProducts>
      <S1>1001</S1>
      <S2>1986</S2>
   </Standard>
    <Standard>
      <ProductID>200058</ProductID>
      <Prefix>ISO</Prefix>
      <SNumber>1002</SNumber>
      <RelatedProducts>
         <RelatedProduct>
                <ProductID>1500167</ProductID>
            <RelationType>DraftProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID>263974</ProductID>
                <RelationId>708519</RelationId>
                <Designation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
            <RelationType>ReferenceProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID>320052</ProductID>
                <RelationId>934754</RelationId>
                <Designation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
            <RelationType>ReferenceProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
                <RelationId>116837</RelationId>
                <Relationship>Identical</Relationship>
                <Designation>NEN ISO 1001</Designation>
            <RelationType>RelatedIntProducts</RelationType>
         </RelatedProduct>
         <RelatedProduct>
                <ProductID>208074</ProductID>
                <RelationId>116843</RelationId>
                <Relationship>Identical</Relationship>
                <Designation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
            <RelationType>RelatedIntProducts</RelationType>
         </RelatedProduct>
      </RelatedProducts>
      <S1>1005</S1>
      <S2>1983</S2>
   </Standard>
</Standards>