collection()

Description

collection() returns a sequence of nodes from a collection identified by a URI. A collection is a processor-defined set of nodes — typically a set of XML documents. The most common use in Saxon is to pass a directory URI, which the processor expands to all XML files in that directory.

When called without an argument (or with the empty sequence), the default collection is returned. The default collection may be set programmatically via the processor’s API.

The exact semantics of the URI are implementation-defined.

Parameters

Return value

node()* — a sequence of nodes from the collection, typically document nodes.

Examples

Process all XML files in a directory (Saxon)

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/">
    <catalog>
      <xsl:for-each select="collection('file:///data/books/?select=*.xml')">
        <book uri="{document-uri(.)}">
          <title><xsl:value-of select="*/title"/></title>
        </book>
      </xsl:for-each>
    </catalog>
  </xsl:template>
</xsl:stylesheet>

Output (example with two files):

<catalog>
  <book uri="file:///data/books/book1.xml">
    <title>Learning XSLT</title>
  </book>
  <book uri="file:///data/books/book2.xml">
    <title>XPath in Practice</title>
  </book>
</catalog>

Merge elements from all collected documents

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/">
    <merged>
      <xsl:for-each select="collection('file:///data/reports/?select=*.xml')/report/entry">
        <xsl:copy-of select="."/>
      </xsl:for-each>
    </merged>
  </xsl:template>
</xsl:stylesheet>

Notes

• The URI syntax for directory collections is Saxon-specific: file:///path/?select=*.xml selects XML files; recurse=yes enables recursive directory traversal.
• Saxon also supports catalog-style collection documents (an XML file listing URIs).
• The order of nodes in the returned sequence is implementation-defined.
• For a sequence of URIs rather than document nodes, use uri-collection().

See also

• uri-collection()
• document-uri()