Implements support for shorthand XPointers (= id-based lookup). We treat them here as if they
were a pointerpart too.
Note that although this is implemented here, this feature depends on the presence of a DTD,
and a validating parser. Currently, this means its unuseable within Cocoon.
process(XPointerContext xpointerContext)
If this pointer part successfully identifies any subresources, it should
stream them to the XMLConsumer available from the XPointerContext and return true.
If this pointer part successfully identifies any subresources, it should
stream them to the XMLConsumer available from the XPointerContext and return true.
Otherwise this method should return false.