Add a default valued node if that node does not exists in xml

cdcatalog.xsl

<?xml version="1.0" encoding="UTF-8"?>
<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="/*">
	 <xsl:copy>
		<xsl:apply-templates />

		<xsl:if test="count(defaultx) = 0">
			<defaultx>||| DEFAULT VALUE FOR X |||</defaultx>
		</xsl:if>

		<xsl:if test="count(defaulty) = 0">
			<defaulty>||| DEFAULT VALUE FOR Y |||</defaulty>
		</xsl:if>
	</xsl:copy>
  </xsl:template>
</xsl:stylesheet>

example.xml

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="cdcatalog.xsl"?>
<catalog>
  <atag>
	<btag attrib="attr">serkan</btag>
  </atag>
  <cd>
    <title>Empire Burlesque</title>
    <artist>Bob Dylan</artist>
    <country>USA</country>
    <company>Columbia</company>
    <price>10.90</price>
    <year>1985</year>
  </cd>
  <cd>
    <title>Hide your heart</title>
    <artist>Bonnie Tyler</artist>
    <country>UK</country>
    <company>CBS Records</company>
    <price>9.90</price>
    <year>1988</year>
  </cd>
  <defaulty>||| CUSTOM VALUE FOR Y |||</defaulty>
  <cd>
    <title>Greatest Hits</title>
    <artist>Dolly Parton</artist>
    <country>USA</country>
    <company>RCA</company>
    <price>9.90</price>
    <year>1982</year>
  </cd>

</catalog>