Package net.sf.saxon.query

Class ImportedFunctionLibrary

java.lang.Object

net.sf.saxon.query.ImportedFunctionLibrary

All Implemented Interfaces:

FunctionLibrary, XQueryFunctionBinder

public class ImportedFunctionLibrary
extends Object
implements FunctionLibrary, XQueryFunctionBinder

This implementation of FunctionLibrary contains all the functions imported into a Query Module. It is implemented as a view of the "global" XQueryFunctionLibrary for the whole query, selecting only those functions that are in an imported namespace.

Constructor Summary

Constructors

Constructor	Description
ImportedFunctionLibrary(QueryModule importingModule, XQueryFunctionLibrary baseLibrary)	Create an imported function library

Method Summary

Modifier and Type	Method	Description
void	addImportedNamespace(NamespaceUri namespace)	Add an imported namespace
Expression	bind(SymbolicName.F symbolicName, Expression[] staticArgs, Map<StructuredQName,Integer> keywords, StaticContext env, List<String> reasons)	Bind an extension function, given the URI and local parts of the function name, and the list of expressions supplied as arguments.
boolean	bindUnboundFunctionCall(UserFunctionCall call, List<String> reasons)	Bind a function call using this XQuery function library, in the situation where it was not possible to bind it earlier, typically because it was encountered as a forwards reference.
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.
XQueryFunction	getDeclaration(StructuredQName functionName, int staticArgs)	Get the function declaration corresponding to a given function name and arity
FunctionItem	getFunctionItem(SymbolicName.F functionName, StaticContext staticContext)	Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.
boolean	isAvailable(SymbolicName.F functionName, int languageLevel)	Test whether a function with a given name and arity is available
void	setImportingModule(QueryModule importingModule)	Set the module that imports this function libary

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.functions.FunctionLibrary

setConfiguration

Constructor Details

ImportedFunctionLibrary

public ImportedFunctionLibrary(QueryModule importingModule,
 XQueryFunctionLibrary baseLibrary)

Create an imported function library

Parameters:

importingModule - the module importing the library

baseLibrary - the function library of which this is a subset view

Method Details

addImportedNamespace

public void addImportedNamespace(NamespaceUri namespace)

Add an imported namespace

Parameters:

namespace - the imported namespace

bind

public Expression bind(SymbolicName.F symbolicName,
 Expression[] staticArgs,
 Map<StructuredQName,Integer> keywords,
 StaticContext env,
 List<String> reasons)
                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:

symbolicName - the name of the function to be bound

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.

The conventions of the XPath language demand that the results of a function depend only on the values of the expressions supplied as arguments, and not on the form of those expressions. For example, the result of f(4) is expected to be the same as f(2+2). The actual expression is supplied here to enable the binding mechanism to select the most efficient possible implementation (including compile-time pre-evaluation where appropriate).

keywords - May be null if no keywords are used in the function call. Otherwise, a map identifying the keywords appearing in the function call, and the 0-based position at which they appeared.

env - The static context of the function call

reasons - If no matching function is found by the function library, it may add a diagnostic explanation to this list explaining why none of the available functions could be used.

Returns:

An object representing the function to be called, if one is found; null if no function was found matching the required name and arity.

Throws:

XPathException - if a matching function was identified, but the call is incorrect, for example because it uses incorrect argument keywords

getDeclaration

public XQueryFunction getDeclaration(StructuredQName functionName,
 int 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 number of expressions supplied as arguments in the function call

Returns:

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

bindUnboundFunctionCall

public boolean bindUnboundFunctionCall(UserFunctionCall call,
 List<String> reasons)

Bind a function call using this XQuery function library, in the situation where it was not possible to bind it earlier, typically because it was encountered as a forwards reference.

Specified by:

bindUnboundFunctionCall in interface XQueryFunctionBinder

Parameters:

call - The unbound function call, which will include a non-null UnboundFunctionCallDetails

reasons - a list which can be populated with messages indicating why binding failed

Returns:

true if the function call is now bound; false if it remains unbound.

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.

setImportingModule

public void setImportingModule(QueryModule importingModule)

Set the module that imports this function libary

Parameters:

importingModule - the importing module

getFunctionItem

public FunctionItem getFunctionItem(SymbolicName.F functionName,
 StaticContext staticContext)
                             throws XPathException

Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.

This supports the function-lookup() function in XPath 3.0.

Specified by:

getFunctionItem in interface FunctionLibrary

Parameters:

functionName - the qualified name of the function being called

staticContext - the static context to be used by the function, in the event that it is a system function with dependencies on the static context

Returns:

if a function of this name and arity is available for calling, then a corresponding function item; or null if the function does not exist

Throws:

XPathException - in the event of certain errors, for example attempting to get a function that is private

isAvailable

public boolean isAvailable(SymbolicName.F functionName,
 int languageLevel)

Test whether a function with a given name and arity is available

This supports the function-available() function in XSLT.

Specified by:

isAvailable in interface FunctionLibrary

Parameters:

functionName - the qualified name of the function being called

languageLevel - the XPath language level times 10 (31 = XPath 3.1)

Returns:

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