org.jaxen

Interface FunctionContext

All Known Implementing Classes:

SimpleFunctionContext, XPathFunctionContext

public interface FunctionContext

Implemented by classes that know how to resolve XPath function names and namespaces to implementations of these functions.

By using a custom FunctionContext, new or different functions may be installed and available to XPath expression writers.

Author:

bob mcwhirter

See Also:

XPathFunctionContext

Method Summary

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.

Method Detail

getFunction

Function getFunction(String namespaceURI,
                     String prefix,
                     String localName)
              throws UnresolvableException

An implementation should return a 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.

Parameters:

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 expression

localName - the local name of the function-call expression. If there is no prefix, then this is the whole name of the function.

Returns:

a Function implementation object.

Throws:

UnresolvableException - when the function cannot be resolved