IBM Version 5 manual XPointer paths and steps

The XML Pointer Language (XPointer), the language defined to express fragment identifiers for any URI reference that locates a resource whose Internet media type is one of text/xml, application/xml, text/xml-external-parsed-entity,or application/xml-external-parsed-entity.

Some examples of Xpointers follow. Each of these selects a particular element in a document.

The example finds the element with the ID United:

http://www.airlines.com/airline.xml#xpointer(id("United"))

The example finds the second language element in the document:

http://www.airlines.com/airline.xml#xpointer(descendant::language[position()=2]

)

The third example is a shorthand form of finding the element with the ID United.

http://www.airlines.com/airline.xml#United

The next two examples are more involved. It shows how one navigates down a, say a DOM tree. Here is shows the navigation from the root node, to the ‘spec’ child, and from it to all the second language elements from any of the child elements:

http://www.airlines.com/airline.xml#xpointer(/child::spec/child::body/child::*/

child::language[2])

http://www.airlines.com/airline.xml#xpointer(/spec/body/*/language[2])

The last example finds the second child element of the fourteenth child element of the root element:

http://www.airlines.com/airline.xml#/1/14/2

The final URI also points to the element with the ID United. However, if no such element is present, it then finds the element with the ID UNITED:

http://www.airlines.com/airline.xml#xpointer(id("United"))xpointer(id("UNITED")

)

XPointer paths and steps

A XPointer path is made up from a number of steps. From a context node, each step will relatively locate a specific point in the document. A location step has three points: axis, node test and an optional predicate. This is in the form:

axis::node-test[predicate]

For aircraft::ROW[position()=34]:

￿The axis is aircraft

30 The XML Files: Development of XML/XSL Applications Using WebSphere Studio