net.sf.saxon.functions
Class FunctionLibraryList

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

All Implemented Interfaces:

Serializable, FunctionLibrary, XQueryFunctionBinder

public class FunctionLibraryList
extends Object
implements FunctionLibrary, XQueryFunctionBinder

A FunctionLibraryList is a list of FunctionLibraries. It is also a FunctionLibrary in its own right. When required, it searches the list of FunctionLibraries to find the required function.

See Also:

Serialized Form

Field Summary

List	libraryList

Constructor Summary

FunctionLibraryList()

Method Summary

int	addFunctionLibrary(FunctionLibrary lib) Add a new FunctionLibrary to the list of FunctionLibraries in this FunctionLibraryList.
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.
FunctionLibrary	get(int n) Get the n'th function library in the list
XQueryFunction	getDeclaration(int nameCode, String uri, String local, Expression[] staticArgs) Get the function declaration corresponding to a given function name and arity
List	getLibraryList() Get the list of contained FunctionLibraries.
boolean	isAvailable(int fingerprint, String uri, String local, int arity) Test whether an extension 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

libraryList

public List libraryList

Constructor Detail

FunctionLibraryList

public FunctionLibraryList()

Method Detail

addFunctionLibrary

public int addFunctionLibrary(FunctionLibrary lib)

Add a new FunctionLibrary to the list of FunctionLibraries in this FunctionLibraryList. Note that libraries are searched in the order they are added to the list.

Parameters:

lib - A function library to be added to the list of function libraries to be searched.

Returns:

the position of the library in the list

get

public FunctionLibrary get(int n)

Get the n'th function library in the list

isAvailable

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

Test whether an extension 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 arguments to the function call. The length of this array represents the arity of the function. The intention is that the static type of the arguments (obtainable via getItemType() and getCardinality() may be used as part of the binding algorithm. In some cases it may be possible for the function to be pre-evaluated at compile time, for example if these expressions are all constant values.

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.

getDeclaration

public XQueryFunction getDeclaration(int nameCode,
                                     String uri,
                                     String local,
                                     Expression[] staticArgs)

Get the function declaration corresponding to a given function name and arity

Specified by:

getDeclaration in interface XQueryFunctionBinder

Returns:

the XQueryFunction if there is one, or null if not.

getLibraryList

public List getLibraryList()

Get the list of contained FunctionLibraries. This method allows the caller to modify the library list, for example by adding a new FunctionLibrary at a chosen position, by removing a library from the list, or by changing the order of libraries in the list. Note that such changes may violate rules in the language specifications, or assumptions made within the product.

Returns:

a list whose members are of class FunctionLibrary

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.