Creating new attribute based on another attribute value in XML using XSLT

Question

I just started learning xslt. I need this input xml file :

<response>
<type>Some type</type>
<attribute name="First"/>
<attribute name="Second"/>
...
<attribute name="nth"/>
  <attribute name="start_action">
    <ActionValue>
      <entryMap name="entryvalue1">
        <action>
          <type>some app statement</type>
          <attribute name="type" value="apps jump" />
        </action>
      </entryMap>
      <entryMap name="entryvalue2">
        <action>
          <type>some phase statement</type>
          <attribute name="type" value="phases2" />
        </action>
      </entryMap>
      <entryMap name="entryvalue3">
        <action>
          <type>some phase statement</type>
          <attribute name="type" value="phases3" />
        </action>
      </entryMap>
      <entryMap name="...">
        <action>
          <type>...</type>
          <attribute name="type" value="..." />
        </action>
      </entryMap>
    </ActionValue>
  </attribute>
</response>

(The ... are for generalizing the input xml so that more phases and apps sections can be added.)

to be transformed to this output xml file :

<response>
<type>Some type</type>
<attribute name="First"/>
<attribute name="Second"/>
...
<attribute name="nth"/>
  <attribute name="start_action">
    <ActionValue>
      <entryMap name="entryvalue1">
        <action>
          <type>some app statement</type>
          <attribute name="type" value="apps jump" />
          <attribute name="app_name" value="entryvalue1" />
        </action>
      </entryMap>
      <entryMap name="entryvalue2">
        <action>
          <type>some phase statement</type>
          <attribute name="type" value="phases2" />
          <attribute name="phase_name" value="entryvalue2" />
        </action>
      </entryMap>
      <entryMap name="entryvalue3">
        <action>
          <type>some phase statement</type>
          <attribute name="type" value="phases3" />
          <attribute name="phase_name" value="entryvalue3" />
        </action>
      </entryMap>
      <entryMap name="...">
        <action>
          <type>...</type>
          <attribute name="type" value="..." />
          <attribute name="..." value="..." />
        </action>
      </entryMap>
    </ActionValue>
  </attribute>
</response>

So, in the input file when I have <attribute name="type" value="apps jump" /> I need to add <attribute name="app_name" value="entryvalue1" /> right after <attribute name="type" value="apps jump" />. And when I have <attribute name="type" value="phases2" /> or <attribute name="type" value="phases3" /> or ANY VALUE in value="" in <attribute name="type"> other than "apps jump" then I need to add <attribute name="phase_name" value="entryvalue2" /> right after the attribute with type element i.e. for the 2nd case <attribute name="type" value="phases2" />. Also, the value in <attribute name="app_name" value="entryvalue1" /> and <attribute name="phase_name" value="entryvalue2" /> and so on, holds the value of their corresponding entryMap name value.

Here for this example I have 1 app and 2 phase sections with app defined first and then the 2 phases are defined but that is not fixed. I can have multiple app and phase sections in any position in my input xml but on the same level. For eg. I can have 2 apps and then 3 phases and then 6 apps and then 1 phase. So I'm trying to create a generalized xslt which will work on any number of app and phase sections.

The current sample XSLT I have right now is this :

<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>

  <!-- Identity transform -->
  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>
  
  <xsl:template match="action">
    <xsl:copy>
        <xsl:copy-of select="*"/>
        <attribute name="phase_name" value="{../@name}"/>
        <attribute name="app_name" value="{../@name}"/>
    </xsl:copy>
</xsl:template>

<xsl:template match="action">
        <xsl:for-each select="attribute">
            <xsl:if test="@name='phase_name'">
            <xsl:value-of select="@value"/>
            </xsl:if>
            <xsl:if test="@name='app_name'">
            <xsl:value-of select="@value"/>
            </xsl:if>
        </xsl:for-each>
</xsl:template>
</xsl:stylesheet>

I am not able to incorporate my logic into the XSLT. If someone could please help me out with this, I'd be very grateful. Thank you in advance.

Answer 1

You've written the problem description as a set of condition-action rules, which is great: what you need to do is translate these directly into template rules. For example:

So, in the input file when I have <attribute name="type" value="apps jump" /> I need to add <attribute name="app_name" value="entryvalue1" /> right after <attribute name="type" value="apps jump" />.

That becomes

<xsl:template match="attribute[@name='type'][@value='apps jump']">
  <xsl:copy/>
  <attribute name="app_name" value="{ancestor::entryMap/@name}"/>
</xsl:template

And when I have <attribute name="type" value="phases2" /> or <attribute name="type" value="phases3" /> or ANY VALUE in value="" in <attribute name="type"> other than "apps jump" then I need to add <attribute name="phase_name" value="entryvalue2" /> right after the attribute with type element i.e. for the 2nd case <attribute name="type" value="phases2" />.

This one becomes something like

<xsl:template match="attribute[@name='type'][@value!='apps jump']">
  <xsl:copy/>
  <attribute name="app_name" value="{ancestor::entryMap/@name}"/>
</xsl:template>

But I obviously haven't quite understood your logic because these rules are identical. I'm not sure whether entryMap1 etc in your rules are literal values or values taken from the source document.