xml - XSLT document('') function doesn't work

Question

As I understand from docs, XSLT function document() with empty string as parameter should read current XSLT document. But the following code doesn't work:

  <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <state>test2</state>
   <xsl:template match="/">
      test1
      <xsl:value-of select="document('')/*/state"/>
    </xsl:template>
   </xsl:stylesheet>

When I apply this XSLT to some XML (just for example), I have only "test1" as output. Why line

 <xsl:value-of select="document('')/*/state"/>

doesn't print "test2"?

Answer 1

The definition of document('') is that it reads the XML document whose URI is the same as the base URI of the instruction in the stylesheet containing the document('') call. Unless you use external entities, this is normally the same as the base URI of the stylesheet module. If it doesn't work, this is often because the base URI of the stylesheet module is unknown. This can easily happen if the XSLT processor is given a stylesheet that's in memory (for example as a character string or a DOM) rather than a resource retrieved via a URI. For example, if you use a JAXP StreamSource and don't call setSystemId() then the base URI will be unknown.