Package net.sf.saxon.query

Class ImportedFunctionLibrary

  • All Implemented Interfaces:
    FunctionLibrary, XQueryFunctionBinder
    public class ImportedFunctionLibrary
extends java.lang.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 Detail

      • 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 Detail

      • addImportedNamespace

        public void addImportedNamespace​(java.lang.String namespace)
        Add an imported namespace
        Parameters:
        namespace - the imported namespace

      • bind

        public Expression bind​(SymbolicName.F symbolicName,
                       Expression[] staticArgs,
                       StaticContext env,
                       java.util.List<java.lang.String> reasons)
        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).

        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.

      • 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.

      • 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 Function 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