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added in API level 8

XPathFunctionResolver

public interface XPathFunctionResolver

javax.xml.xpath.XPathFunctionResolver


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.

Summary

Public methods

abstract XPathFunction resolveFunction(QName functionName, int arity)

Find a function in the set of available functions.

Public methods

resolveFunction

added in API level 8
public abstract XPathFunction resolveFunction (QName functionName, 
                int arity)

Find a function in the set of available functions.

If functionName or arity is null, then a NullPointerException is thrown.

Parameters
functionName QName: The function name.

arity int: The number of arguments that the returned function must accept.

Returns
XPathFunction The function or null if no function named functionName with arity arguments exists.

Throws
NullPointerException If functionName or arity is null.