net.sf.saxon.style
Class StylesheetFunctionLibrary

java.lang.Object
  net.sf.saxon.style.StylesheetFunctionLibrary

All Implemented Interfaces:

Serializable, FunctionLibrary

public class StylesheetFunctionLibrary
extends Object
implements FunctionLibrary

A StylesheetFunctionLibrary contains functions defined by the user in a stylesheet. This library is used at compile time only, as it contains references to the actual XSLFunction objects. Binding to a function in this library registers the function call on a fix-up list to be notified when the actual compiled function becomes available.

See Also:

Serialized Form

Constructor Summary

StylesheetFunctionLibrary(PrincipalStylesheetModule sheet, boolean overriding)
Create a FunctionLibrary that provides access to stylesheet functions

Method Summary

Expression	bind(StructuredQName functionName, 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.
SequenceType[]	getFunctionSignature(StructuredQName functionName, int arity) Test whether a function with a given name and arity is available; if so, return its signature.
boolean	isOverriding() Ask whether the functions in this library are "overriding" functions, that is, defined with xsl:function override="yes".

Methods inherited from class java.lang.Object

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

Constructor Detail

StylesheetFunctionLibrary

public StylesheetFunctionLibrary(PrincipalStylesheetModule sheet,
                                 boolean overriding)

Create a FunctionLibrary that provides access to stylesheet functions

Parameters:

sheet - The XSLStylesheet element of the principal stylesheet module

overriding - set to true if this library is to contain functions specifying override="yes", or to false if it is to contain functions specifying override="no". (XSLT uses two instances of this class, one for overriding functions and one for non-overriding functions.)

Method Detail

isOverriding

public boolean isOverriding()

Ask whether the functions in this library are "overriding" functions, that is, defined with xsl:function override="yes".

Returns:

true if these are overriding functions, false otherwise

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.

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.

Specified by:

getFunctionSignature in interface FunctionLibrary

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

bind

public Expression bind(StructuredQName functionName,
                       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 -

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 and arity.

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; or if this function library "owns" the namespace containing the function call, but no function was found.

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.