net.sf.saxon.functions
Class VendorFunctionLibrary

java.lang.Object
  extended by net.sf.saxon.functions.VendorFunctionLibrary
All Implemented Interfaces:
Serializable, FunctionLibrary
Direct Known Subclasses:
ExtraFunctionLibrary

public class VendorFunctionLibrary
extends 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.
 boolean isAvailable(StructuredQName functionName, int arity)
          Test whether a Saxon function with a given name and arity is available.
 Expression makeSaxonFunction(String localName, StaticContext env, Expression[] arguments)
          Make a Saxon function with a given name
static String pluralArguments(int num)
          Utility routine used in constructing error messages
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

VendorFunctionLibrary

public VendorFunctionLibrary()
Create the Vendor Function Library for Saxon

Method Detail

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(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 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.


Copyright (C) Michael H. Kay. All rights reserved.