XSLT - Check if two nodes are equal in a for-each loop

Question

This is my XML:

<Shipment>
<AddressData>   
    <Sender>
        <PartnerID>123</PartnerID>
        <Name1>Test</Name1>         
    </Sender>
    <Receiver>
        <PartnerID>124</PartnerID>
        <Name1>Test 2</Name1>       
    </Receiver>
</AddressData>
<Packaging>
    <Package>
        <ID>1</ID>
        <Length>20</Length>
        <Width>20</Width>           
        <PackageType>Carton</PackageType>
    </Package>
    <Package>
        <ID>2</ID>
        <Length>20</Length>
        <Width>20</Width>           
        <PackageType>Carton</PackageType>
    </Package>
</Packaging>
<Items>
    <Item>
        <PackageID>1</PackageID>
        <Partnumber>1234</Partnumber>
        <Quantity>3</Quantity>
    </Item>
    <Item>
        <PackageID>1</PackageID>
        <Partnumber>1235</Partnumber>
        <Quantity>3</Quantity>
    </Item>
    <Item>
        <PackageID>1</PackageID>
        <Partnumber>1236</Partnumber>
        <Quantity>3</Quantity>
    </Item>
    <Item>
        <PackageID>2</PackageID>
        <Partnumber>1232</Partnumber>
        <Quantity>3</Quantity>
    </Item>
    <Item>
        <PackageID>2</PackageID>
        <Partnumber>12322</Partnumber>
        <Quantity>3</Quantity>
    </Item>
</Items>

What I'm trying to acomplish is to list the relevant items of each package directly in the Packaging XML field.

So that I will become the following result:

<Shipment>
<AddressData>
    <Sender>
        <PartnerID>123</PartnerID>
        <Name1>Test</Name1>         
    </Sender>
    <Receiver>
        <PartnerID>124</PartnerID>
        <Name1>Test 2</Name1>       
    </Receiver>
</AddressData>
<Packaging>
    <Package>
        <ID>1</ID>
        <Length>20</Length>
        <Width>20</Width>           
        <PackageType>Carton</PackageType>
        <Items>
            <Item>
                <PackageID>1</PackageID>
                <Partnumber>1234</Partnumber>
                <Quantity>3</Quantity>
            </Item>
            <Item>
                <PackageID>1</PackageID>
                <Partnumber>1235</Partnumber>
                <Quantity>3</Quantity>
            </Item>
            <Item>
                <PackageID>1</PackageID>
                <Partnumber>1236</Partnumber>
                <Quantity>3</Quantity>
            </Item>
        </Items>
    </Package>
    <Package>
        <ID>2</ID>
        <Length>20</Length>
        <Width>20</Width>           
        <PackageType>Carton</PackageType>
        <Items>
            <Item>
                <PackageID>2</PackageID>
                <Partnumber>1232</Partnumber>
                <Quantity>3</Quantity>
            </Item>
            <Item>
                <PackageID>2</PackageID>
                <Partnumber>12322</Partnumber>
                <Quantity>3</Quantity>
            </Item>
        </Items>
    </Package>
</Packaging>

</Shipment>

What I've tried to do is the following XSLT Tranformation:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
</xsl:template>
<xsl:template match="Items">
</xsl:template>

<xsl:template match="Packaging">
    <Packaging>
        <xsl:for-each select="Package">
            <ID>
                <xsl:value-of select="ID"/>
            </ID>
            <Length>
                <xsl:value-of select="Length"/>
            </Length>
            <Width>
                <xsl:value-of select="Width"/>
            </Width>
            <PackageType>
                <xsl:value-of select="PackageType"/>
            </PackageType>
            <Items>
                <xsl:for-each select="../../Items/Item">
                    <xsl:if test="PackageID = ../../Packaging/Package/ID">
                    <Item>
                        <PackageID><xsl:value-of select="PackageID"/></PackageID>
                        <Partnumber><xsl:value-of select="Partnumber"/></Partnumber>
                        <Quantity><xsl:value-of select="Quantity"/></Quantity>
                    </Item>
                    </xsl:if>
                </xsl:for-each>
            </Items>
        </xsl:for-each>
    </Packaging>
</xsl:template>
</xsl:stylesheet>

My current XSLT Transformation isn't working because all Items regardless of the ID will be shown. So the if statement seems to be not working correctly.

Thanks

Answer 1

The issue is that as soon as you do xsl:for-each select="../../Items/Item" you are in a different context, and your previous context (of the Package) is effectively "forgotten".

What you can do is store the current package id in a variable before selecting the items, and use that in the compate

<Items>
    <xsl:variable name="packageId" select="ID" />
    <xsl:for-each select="../../Items/Item">
        <xsl:if test="PackageID = $packageId">
        <Item>
            <PackageID><xsl:value-of select="PackageID"/></PackageID>
            <Partnumber><xsl:value-of select="Partnumber"/></Partnumber>
            <Quantity><xsl:value-of select="Quantity"/></Quantity>
        </Item>
        </xsl:if>
    </xsl:for-each>
</Items>

In fact, you can put your condition in the select of the xsl:for-each rather than do an xsl:if

<xsl:variable name="packageId" select="ID" />
<xsl:for-each select="../../Items/Item[PackageID = $packageId]">

In this case, this condition could reference the current package node, with current()

<xsl:for-each select="../../Items/Item[PackageID = current()/ID]">

But having said that, it may be even better to use xsl:key here. Define a key like so (as a child of xsl:stylesheet )

<xsl:key name="items" match="Item" use="PackageID" />

Then, you can do this...

<xsl:for-each select="key('items', ID)">

In fact, you don't even need xsl:for-each here at all. Use xsl:apply-templates and take advantage of the identity template.

Try this simplified XSLT:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" />
<xsl:key name="items" match="Item" use="PackageID" />

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

<xsl:template match="Items" />

<xsl:template match="Package">
    <Package>
        <xsl:apply-templates />
        <Items>
          <xsl:apply-templates select="key('items', ID)" />
        </Items>
    </Package>
</xsl:template>
</xsl:stylesheet>