Package net.sf.saxon.functions

Class FunctionLibraryList

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

    • 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

      • 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

      • bind

        public Expression bind​(SymbolicName.F functionName,
                       Expression[] staticArgs,
                       java.util.Map<StructuredQName,​java.lang.Integer> keywords,
                       StaticContext env,
                       java.util.List<java.lang.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:
        functionName - The name of the function
        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.
        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
        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 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 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,
                                       java.util.List<java.lang.String> reasons)
        Bind a function call using this 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.

      • getLibraryList

        public java.util.List<FunctionLibrary> 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.