javax.xml.xpath.XPathFunctionResolver |
XPathFunctionResolver
provides access to the set of user defined
XPathFunction
s.
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.
Public Methods | |||||||||||
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|
Find a function in the set of available functions. |
Find a function in the set of available functions.
If
functionName
or
arity
is
null
, then a
NullPointerException
is thrown.
functionName | The function name. |
---|---|
arity | The number of arguments that the returned function must accept. |
null
if no function named
functionName
with
arity
arguments exists.
NullPointerException |
If
functionName
or
arity
is
null
.
|
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