net.sf.saxon.xpath

Class XPathFunctionLibrary

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.
Constructor Summary
XPathFunctionLibrary()
Construct a XPathFunctionLibrary
Method Summary
Expressionbind(StructuredQName functionName, Expression[] staticArgs, StaticContext env)
Bind a function, given the URI and local parts of the function name, and the list of expressions supplied as arguments.
FunctionLibrarycopy()
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.
SequenceType[]getFunctionSignature(StructuredQName functionName, int arity)
Test whether a function with a given name and arity is available; if so, return its signature.
XPathFunctionResolvergetXPathFunctionResolver()
Get the resolver
voidsetXPathFunctionResolver(XPathFunctionResolver resolver)
Set the resolver

Constructor Detail

XPathFunctionLibrary

public XPathFunctionLibrary()
Construct a XPathFunctionLibrary

Method Detail

bind

public Expression bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env)
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.

Parameters: functionName 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

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.

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.

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

getFunctionSignature

public SequenceType[] getFunctionSignature(StructuredQName functionName, int arity)
Test whether a function with a given name and arity is available; if so, return its signature. This supports the function-available() function in XSLT; it is also used to support higher-order functions introduced in XQuery 1.1. For this function library the method is never used and therefore returns null.

This method may be called either at compile time or at run time. If the function library is to be used only in an XQuery or free-standing XPath environment, this method may throw an UnsupportedOperationException.

Parameters: functionName the qualified name of the function being called arity The number of arguments. This is set to -1 in the case of the single-argument function-available() function; in this case the method should return true if there is some function of this name available for calling.

Returns: if a function of this name and arity is available for calling, then the type signature of the function, as an array of sequence types in which the zeroth entry represents the return type; or a zero-length array if the function exists but the signature is not known; or null if the function does not exist

getXPathFunctionResolver

public XPathFunctionResolver getXPathFunctionResolver()
Get the resolver

Returns: the XPathFunctionResolver wrapped by this FunctionLibrary

setXPathFunctionResolver

public void setXPathFunctionResolver(XPathFunctionResolver resolver)
Set the resolver

Parameters: resolver The XPathFunctionResolver wrapped by this FunctionLibrary