net.sf.saxon.functions
Class SystemFunctionLibrary

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

All Implemented Interfaces:

Serializable, FunctionLibrary

public class SystemFunctionLibrary
extends Object
implements FunctionLibrary

The SystemFunctionLibrary represents the collection of functions in the fn: namespace. That is, the functions defined in the "Functions and Operators" specification, optionally augmented by the additional functions defined in XSLT.

See Also:

Serialized Form

Field Summary

static int	FULL_XSLT
static int	USE_WHEN
static int	XPATH_ONLY

Constructor Summary

SystemFunctionLibrary(int functionSet)
Create a SystemFunctionLibrary

Method Summary

Expression	bind(int nameCode, String uri, String local, Expression[] staticArgs) 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(int fingerprint, String uri, String local, int arity) Test whether a system function with a given name and arity is available.

Methods inherited from class java.lang.Object

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

Field Detail

XPATH_ONLY

public static final int XPATH_ONLY

See Also:

Constant Field Values

FULL_XSLT

public static final int FULL_XSLT

See Also:

Constant Field Values

USE_WHEN

public static final int USE_WHEN

See Also:

Constant Field Values

Constructor Detail

SystemFunctionLibrary

public SystemFunctionLibrary(int functionSet)

Create a SystemFunctionLibrary

Parameters:

functionSet - determines the set of functions allowed. One of XPATH_ONLY, FULL_XSLT, USE_WHEN

Method Detail

isAvailable

public boolean isAvailable(int fingerprint,
                           String uri,
                           String local,
                           int arity)

Test whether a system 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:

uri - The URI of the function name

local - The local part of the function name

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 matching extension function, regardless of its arity.

fingerprint - The namepool fingerprint of the function name. This must match the uri and localName; the information is provided redundantly to avoid repeated lookups in the name pool.

bind

public Expression bind(int nameCode,
                       String uri,
                       String local,
                       Expression[] staticArgs)
                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:

uri - The URI of the function name

local - The local part of the function name

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.

nameCode - The namepool nameCode of the function name. The uri and local name are also supplied (redundantly) to avoid fetching them from the name pool.

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.