net.sf.saxon.functions
Class VendorFunctionLibrary

java.lang.Object
  net.sf.saxon.functions.VendorFunctionLibrary

All Implemented Interfaces:

java.io.Serializable, FunctionLibrary

Direct Known Subclasses:

ExtraFunctionLibrary

public class VendorFunctionLibrary
extends java.lang.Object
implements FunctionLibrary

The VendorFunctionLibrary represents specially-recognized functions in the Saxon namespace. It doesn't handle Saxon extension functions that are implemented as normal extension functions, which are bound using the JavaExtensionLibrary.

See Also:

Serialized Form

Constructor Summary

VendorFunctionLibrary()
Create the Vendor Function Library for Saxon

Method Summary

Expression	bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env) Bind an extension 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.
protected void	init()
boolean	isAvailable(StructuredQName functionName, int arity) Test whether a Saxon function with a given name and arity is available.
Expression	makeSaxonFunction(java.lang.String localName, StaticContext env, Expression[] arguments) Make a Saxon function with a given name
static java.lang.String	pluralArguments(int num) Utility routine used in constructing error messages
protected StandardFunction.Entry	register(java.lang.String name, java.lang.Class implementationClass, int opcode, int minArguments, int maxArguments, ItemType itemType, int cardinality) Register an extension function in the table of function details.

Methods inherited from class java.lang.Object

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

Constructor Detail

VendorFunctionLibrary

public VendorFunctionLibrary()

Create the Vendor Function Library for Saxon

Method Detail

register

protected StandardFunction.Entry register(java.lang.String name,
                                          java.lang.Class implementationClass,
                                          int opcode,
                                          int minArguments,
                                          int maxArguments,
                                          ItemType itemType,
                                          int cardinality)

Register an extension function in the table of function details.

Parameters:

name - the function name

implementationClass - the class used to implement the function

opcode - identifies the function when a single class implements several functions

minArguments - the minimum number of arguments required

maxArguments - the maximum number of arguments allowed

itemType - the item type of the result of the function

cardinality - the cardinality of the result of the function

Returns:

the entry describing the function. The entry is incomplete, it does not yet contain information about the function arguments.

init

protected void init()

isAvailable

public boolean isAvailable(StructuredQName functionName,
                           int arity)

Test whether a Saxon function with a given name and arity is available. This supports the function-available() function in XSLT. This method may be called either at compile time or at run time.

Specified by:

isAvailable in interface FunctionLibrary

Parameters:

functionName - the name of the function

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

Returns:

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

bind

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

Bind an extension 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 - the name of the function

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 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.

makeSaxonFunction

public Expression makeSaxonFunction(java.lang.String localName,
                                    StaticContext env,
                                    Expression[] arguments)
                             throws XPathException

Make a Saxon function with a given name

Parameters:

localName - the local name of the function

env - the static context

arguments - the arguments of the function

Returns:

an exprssion representing a call on the given function

Throws:

XPathException

pluralArguments

public static java.lang.String pluralArguments(int num)

Utility routine used in constructing error messages

Parameters:

num - a number

Returns:

the string " argument" or " arguments" if num is plural

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.