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(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.
FunctionLibrary	get(int n) Get the n'th function library in the list
XQueryFunction	getDeclaration(StructuredQName functionName, Expression[] staticArgs) Get the function declaration corresponding to a given function name and arity
List	getLibraryList() Get the list of contained FunctionLibraries.
boolean	isAvailable(StructuredQName functionName, 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(StructuredQName functionName,
                           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:

functionName -

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 -

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.

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.

getDeclaration

public XQueryFunction getDeclaration(StructuredQName functionName,
                                     Expression[] staticArgs)

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

Specified by:

getDeclaration in interface XQueryFunctionBinder

Parameters:

functionName - the name of the function as a QName

staticArgs - the expressions supplied as arguments in the function call (typically, we only need to know the number of arguments)

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.