XSLT 1.0 Find unique node with Highest value

Question

I am beginner in XSLT 1.0. I am facing an issue when i tried to find unique node with Highest value.

Source XML:

<Response>
    <Flight>
        <From>A</From>
        <To>B</To>
        <Passengers>
            <Passenger>
                <Fare>200</Fare>
                <Fee>15</Fee>
                <Type>ADT</Type>
            </Passenger>
            <Passenger>
                <Fare>200</Fare>
                <Fee>15</Fee>
                <Type>ADT</Type>
            </Passenger>
            <Passenger>
                <Fare>150</Fare>
                <Fee>15</Fee>
                <Type>CHD</Type>
            </Passenger>
        </Passengers>
    </Flight>
    <Flight>
        <From>B</From>
        <To>A</To>
        <Passengers>
            <Passenger>
                <Fare>250</Fare>
                <Fee>25</Fee>
                <Type>ADT</Type>
            </Passenger>
            <Passenger>
                <Fare>250</Fare>
                <Fee>25</Fee>
                <Type>ADT</Type>
            </Passenger>
            <Passenger>
                <Fare>100</Fare>
                <Fee>25</Fee>
                <Type>CHD</Type>
            </Passenger>
        </Passengers>
    </Flight>
</Response>

As shown in above XML, There is a round trip result for A-B origin destination and i am going to purchase tickets for both the flights. i need to calculate total fare, fee (whichever is highest from both the Flights) and its total price.

Expected Output:

<Result>
    <PassengerGroup TotalFare="1150" TotalFee="75" TotalPrice="1225"/>
</Result>

Here,

• TotalFare is sum of all the Fare tag.
• TotalFee is greater value of each passenger type multiply by no of passenger of that type.
• e.g. For ADT greater Fee value is 25 and number of ADT is 2 so total Fee for ADT is 50. For CHD greater Fee value is 25 and number of CHD is 1 so total Fee for CHD is 25. That makes final total fee = 75.
• TotalPrice is sum of ToatalFare and TotalFee attribute.

I've tried with below XSLT.

XSLT:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
version="1.0" xmlns:exslt="http://exslt.org/common" exclude-result-prefixes="exslt">

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

    <xsl:template match="Response">
        <xsl:element name="Result">
            <xsl:element name="PassengerGroup">
                <xsl:attribute name="TotalFare">
                    <xsl:value-of select="sum(//Flight/Passengers/Passenger/Fare)"/>
                </xsl:attribute>
                <xsl:attribute name="TotalFee">
                    <xsl:value-of select="sum(//Flight/Passengers/Passenger[not(Type=preceding::Passenger/Type)]/Fee)"/>
                </xsl:attribute>
                <xsl:attribute name="TotalFee">
                    <xsl:value-of select="sum(//Flight/Passengers/Passenger/Fare) + sum(//Flight/Passengers/Passenger/Fee)"/>
                </xsl:attribute>
            </xsl:element>
        </xsl:element>
    </xsl:template>
</xsl:stylesheet>

and got the below output.

Output:

<Result>
  <PassengerGroup TotalFare="1150" TotalFee="30" TotalPrice="1270"/>
</Result>

TotalFee is not calculated correctly. Please Help. Thanks.

Answer 1

I believe this should do it:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0" xmlns:exslt="http://exslt.org/common" exclude-result-prefixes="exslt">
  <xsl:output method="xml" indent="yes" />
  <xsl:key name="kPassenger" match="Passenger" use="Type" />

  <!-- The passenger nodes from just the first flight, so we can count how many of 
       each type there are -->
  <xsl:variable name="passengers" select="Response/Flight[1]/Passengers/Passenger" />

  <xsl:template match="Response">
    <xsl:variable name="totalFare" select="sum(Flight/Passengers/Passenger/Fare)" />
    <xsl:variable name="feeByPassenger">
      <xsl:apply-templates 
         select="$passengers[generate-id() = 
                             generate-id(key('kPassenger', Type)[1])]"
         mode="fee" />
    </xsl:variable>
    <xsl:variable name="totalFee" 
                  select="sum(exslt:node-set($feeByPassenger)/*/@value)" />

    <Result>
      <PassengerGroup TotalFare="{$totalFare}" TotalFee="{$totalFee}" 
                      TotalPrice="{$totalFare + $totalFee}" />
    </Result>
  </xsl:template>

  <xsl:template match="Passenger" mode="fee">
    <xsl:variable name="maxFee">
      <xsl:apply-templates select="key('kPassenger', Type)/Fee">
        <xsl:sort select="." data-type="number" order="descending"/>
      </xsl:apply-templates>
    </xsl:variable>
    <fee value="{$maxFee * count($passengers[Type = current()/Type])}"/>
  </xsl:template>

  <xsl:template match="Fee">
    <xsl:if test="position() = 1">
      <xsl:value-of select="." />
    </xsl:if>
  </xsl:template>
</xsl:stylesheet>

When run on your sample input, the result is:

<Result>
  <PassengerGroup TotalFare="1150" TotalFee="75" TotalPrice="1225" />
</Result>