net.sf.saxon.xpath

Class XPathFunctionLibrary

java.lang.Object

net.sf.saxon.xpath.XPathFunctionLibrary

All Implemented Interfaces:

Serializable, FunctionLibrary

public class XPathFunctionLibrary
extends Object
implements FunctionLibrary

The XPathFunctionLibrary is a FunctionLibrary that supports binding of XPath function calls to instances of the JAXP XPathFunction interface returned by an XPathFunctionResolver.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
XPathFunctionLibrary() Construct a XPathFunctionLibrary

Method Summary

Methods

Modifier and Type	Method and Description
Expression	bind(StructuredQName functionName, int arity, Expression[] staticArgs, StaticContext env, Container container) Bind a function, given the URI and local parts of the function name, and the list of expressions supplied as arguments.
FunctionLibrary	copy() This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows new functions to be added, then additions to this copy will not affect the original, or vice versa.
FunctionItem	getFunctionItem(StructuredQName functionName, int arity, StaticContext staticContext) Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.
XPathFunctionResolver	getXPathFunctionResolver() Get the resolver
boolean	isAvailable(StructuredQName functionName, int arity) Test whether a function with a given name and arity is available
void	setXPathFunctionResolver(XPathFunctionResolver resolver) Set the resolver

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

XPathFunctionLibrary

public XPathFunctionLibrary()

Construct a XPathFunctionLibrary

Method Detail

setXPathFunctionResolver

public void setXPathFunctionResolver(XPathFunctionResolver resolver)

Set the resolver

Parameters:

resolver - The XPathFunctionResolver wrapped by this FunctionLibrary

getXPathFunctionResolver

public XPathFunctionResolver getXPathFunctionResolver()

Get the resolver

Returns:

the XPathFunctionResolver wrapped by this FunctionLibrary

bind

public Expression bind(StructuredQName functionName,
              int arity,
              Expression[] staticArgs,
              StaticContext env,
              Container container)
                throws XPathException

Bind a function, given the URI and local parts of the function name, and the list of expressions supplied as arguments. This method is called at compile time.

Specified by:

bind in interface FunctionLibrary

Parameters:

functionName -

arity -

staticArgs - The expressions supplied statically in the function call. The intention is that the static type of the arguments (obtainable via getItemType() and getCardinality() may be used as part of the binding algorithm.

env -

container -

Returns:

An object representing the extension function to be called, if one is found; null if no extension function was found matching the required name, arity, or signature.

Throws:

XPathException - if a function is found with the required name and arity, but the implementation of the function cannot be loaded or used; or if an error occurs while searching for the function.

getFunctionItem

public FunctionItem getFunctionItem(StructuredQName functionName,
                           int arity,
                           StaticContext staticContext)
                             throws XPathException

Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.

This supports the function-lookup() function in XPath 3.0.

Specified by:

getFunctionItem in interface FunctionLibrary

Parameters:

functionName - the qualified name of the function being called

arity - The number of arguments.

staticContext - the static context to be used by the function, in the event that it is a system function with dependencies on the static context

Returns:

if a function of this name and arity is available for calling, then a corresponding function item; or null if the function does not exist

Throws:

XPathException - in the event of certain errors, for example attempting to get a function that is private

isAvailable

public boolean isAvailable(StructuredQName functionName,
                  int arity)

Test whether a function with a given name and arity is available

This supports the function-available() function in XSLT.

Specified by:

isAvailable in interface FunctionLibrary

Parameters:

functionName - the qualified name of the function being called

arity - The number of arguments.

Returns:

true if a function of this name and arity is available for calling

copy

public FunctionLibrary copy()

This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows new functions to be added, then additions to this copy will not affect the original, or vice versa.

Specified by:

copy in interface FunctionLibrary

Returns:

a copy of this function library. This must be an instance of the original class.