public class SimpleFunctionContext extends Object implements FunctionContext
FunctionContext
.
This is a simple table-based key-lookup implementation
for FunctionContext
which can be programmatically
extended by registering additional functions.
XPathFunctionContext
Constructor and Description |
---|
SimpleFunctionContext()
Construct an empty function context.
|
Modifier and Type | Method and Description |
---|---|
Function |
getFunction(String namespaceURI,
String prefix,
String localName)
An implementation should return a
Function implementation object
based on the namespace URI and local name of the function-call
expression. |
void |
registerFunction(String namespaceURI,
String localName,
Function function)
Register a new function.
|
public SimpleFunctionContext()
Construct an empty function context.
public void registerFunction(String namespaceURI, String localName, Function function)
By registering a new function, any XPath expression
that utilizes this FunctionContext
may
refer to and use the new function.
Functions may exist either in a namespace or not.
Namespace prefix-to-URI resolution is the responsibility
of a NamespaceContext
. Within this FunctionContext
functions are only referenced using the URI, not
the prefix.
The namespace URI of a function may be null
to indicate that it exists without a namespace.
namespaceURI
- the namespace URI of the function to
be registered with this contextlocalName
- the non-prefixed local portion of the
function to be registered with this contextfunction
- a Function
implementation object
to be used when evaluating the functionpublic Function getFunction(String namespaceURI, String prefix, String localName) throws UnresolvableException
FunctionContext
Function
implementation object
based on the namespace URI and local name of the function-call
expression.
It must not use the prefix parameter to select an implementation, because a prefix could be bound to any namespace; the prefix parameter could be used in debugging output or other generated information. The prefix may otherwise be completely ignored.
getFunction
in interface FunctionContext
namespaceURI
- the namespace URI to which the prefix parameter
is bound in the XPath expression. If the function
call expression had no prefix, the namespace URI
is null
.prefix
- the prefix that was used in the function call
expressionlocalName
- the local name of the function-call expression.
If there is no prefix, then this is the whole
name of the function.UnresolvableException
- when the function cannot be resolvedCopyright 2001–2022 The Jaxen Project. All rights reserved.