Class ExecutableFunctionLibrary

  • All Implemented Interfaces:

    public class ExecutableFunctionLibrary
    extends java.lang.Object
    implements FunctionLibrary
    An ExecutableFunctionLibrary is a function library that contains definitions of functions for use at run-time. Normally functions are bound at compile-time; however there are various situations in which the information is needed dynamically, for example (a) to support the XSLT function-available() call (in the pathological case where the argument is not known statically), (b) to allow functions to be called from saxon:evaluate(), (c) to allow functions to be called from a debugging breakpoint.
    • Constructor Detail

      • ExecutableFunctionLibrary

        public ExecutableFunctionLibrary​(Configuration config)
        Create the ExecutableFunctionLibrary
        config - the Saxon configuration
    • Method Detail

      • addFunction

        public void addFunction​(UserFunction fn)
        Register a function with the function library
        fn - the function to be registered
      • 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)
        Bind a 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
        functionName - The name of the function to be called
        staticArgs - The expressions supplied statically in the function call. The intention is that the static type of the arguments (obtainable via getItemType() and getCardinality() may be used as part of the binding algorithm.
        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 evaluation 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.
        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.
      • 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
        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
        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
        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
        functionName - the qualified name of the function being called
        languageLevel - the XPath language level, times 10 (31 = XPath 3.1)
        true if a function of this name and arity is available for calling
      • 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
        a copy of this function library. This must be an instance of the original class.
      • getAllFunctions

        public java.lang.Iterable<UserFunction> getAllFunctions()
        Get all the functions defined in this function library.
        an iterable delivering the UserFunction objects representing the user-defined functions in a stylesheet or query