Package net.sf.saxon.ma.map

Class MapFunctionSet.MapMerge

  • All Implemented Interfaces:
    Callable, FunctionItem, GroundedValue, Item, Sequence
    Enclosing class:
    MapFunctionSet
    public static class MapFunctionSet.MapMerge
extends SystemFunction
    Implementation of the function map:merge() => Map From 9.8, map:merge is also used to implement map constructors in XPath and the xsl:map instruction in XSLT. For this purpose it accepts an additional option to define the error code to be used to signal duplicates.

    • Constructor Detail

      • MapMerge

        public MapMerge()

    • Method Detail

      • makeOptimizedFunctionCall

        public Expression makeOptimizedFunctionCall​(ExpressionVisitor visitor,
                                            ContextItemStaticInfo contextInfo,
                                            Expression... arguments)
                                     throws XPathException
        Allow the function to create an optimized call based on the values of the actual arguments
        Overrides:
        makeOptimizedFunctionCall in class SystemFunction
        Parameters:
        visitor - the expression visitor
        contextInfo - information about the context item
        arguments - the supplied arguments to the function call. Note: modifying the contents of this array should not be attempted, it is likely to have no effect.
        Returns:
        either a function call on this function, or an expression that delivers the same result, or null indicating that no optimization has taken place
        Throws:
        XPathException - if an error is detected

      • getResultItemType

        public ItemType getResultItemType​(Expression[] args)
        Get the return type, given knowledge of the actual arguments
        Overrides:
        getResultItemType in class SystemFunction
        Parameters:
        args - the actual arguments supplied
        Returns:
        the best available item type that the function will return

      • call

        public MapItem call​(XPathContext context,
                    Sequence[] arguments)
             throws XPathException
        Description copied from interface: Callable
        Call the Callable.
        Parameters:
        context - the dynamic evaluation context
        arguments - the values of the arguments, supplied as Sequences.

        Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

        If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

        It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

        Returns:
        the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the expression

      • mergeMaps

        public static MapItem mergeMaps​(SequenceIterator iter,
                                XPathContext context,
                                java.lang.String duplicates,
                                java.lang.String duplicatesErrorCode,
                                FunctionItem onDuplicates)
                         throws XPathException
        Merge a sequence of maps into a single map
        Parameters:
        iter - iterator over the input maps
        context - The XPath dynamic context
        duplicates - action to be taken when duplicate keys are encountered
        duplicatesErrorCode - if duplicates are not allowed, the error code to be used
        onDuplicates - callback to be used when duplicates = "use-callback"
        Returns:
        the merged map
        Throws:
        XPathException - if any error occurs, including detection of disallowed duplicates

      • getStreamerName

        public java.lang.String getStreamerName()
        Description copied from class: SystemFunction
        Get a name that identifies the class that can be used to evaluate this function in streaming mode, that is, supplying one item or event at a time as it is delivered by the parser. Special streaming support is generally available in Saxon-EE for all system functions that take a sequence as their argument.
        Overrides:
        getStreamerName in class SystemFunction
        Returns:
        a name that identifies a class that supports streamed evaluation of this system function, or null if no such class is available. The mapping of names to classes is defined in the Saxon-EE class StreamerMap. In non-streaming Saxon editions (HE and PE) the method always returns null.