XPathFunctionResolver provides access to the set of user defined XPathFunctions.
XPath functions are resolved by name and arity.
The resolver is not needed for XPath built-in functions and the resolver
cannot be used to override those functions.
In particular, the resolver is only called for functions in an another
namespace (functions with an explicit prefix). This means that you cannot
use the XPathFunctionResolver to implement specifications
like XML-Signature Syntax
and Processing which extend the function library of XPath 1.0 in the
same namespace. This is a consequence of the design of the resolver.
If you wish to implement additional built-in functions, you will have to
extend the underlying implementation directly. | 