Package net.sf.saxon.functions

Class KeyFn

    • Constructor Detail

      • KeyFn

        public KeyFn()

    • Method Detail

      • getStaticKeyName

        public StructuredQName getStaticKeyName()
        Get the key name, if known statically. If not known statically, return null.
        Returns:
        the key name if known, otherwise null

      • getInternal

        public boolean getInternal()

      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                            ExpressionVisitor.ContextItemType contextItemType)
                     throws XPathException
        Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.
        Overrides:
        typeCheck in class FunctionCall
        Parameters:
        visitor - an expression visitor
        contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
        Returns:
        the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)

      • internalKeyCall

        public static KeyFn internalKeyCall​(KeyDefinitionSet keySet,
                                    java.lang.String name,
                                    Expression value,
                                    Expression doc)
        Non-standard constructor to create an internal call on key() with a known key definition
        Parameters:
        keySet - the set of KeyDefinitions (always a single KeyDefinition)
        name - the name allocated to the key (first argument of the function)
        value - the value being searched for (second argument of the function)
        doc - the document being searched (third argument)
        Returns:
        a call on the key() function

      • computeSpecialProperties

        public int computeSpecialProperties()
        Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if a property bit is set, it is true, but if it is unset, the value is unknown.
        Overrides:
        computeSpecialProperties in class SystemFunction
        Returns:
        the special properties, as a bit-significant integer

      • preEvaluate

        public Expression preEvaluate​(ExpressionVisitor visitor)
        preEvaluate: this method suppresses compile-time evaluation by doing nothing
        Overrides:
        preEvaluate in class FunctionCall
        Parameters:
        visitor - the expression visitor
        Returns:
        the result of the early evaluation, or the original expression, or potentially a simplified expression

      • addToPathMap

        public PathMap.PathMapNodeSet addToPathMap​(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
        Add a representation of a doc() call or similar function to a PathMap. This is a convenience method called by the addToPathMap() methods for doc(), document(), collection() and similar functions. These all create a new root expression in the path map.
        Overrides:
        addToPathMap in class Expression
        Parameters:
        pathMap - the PathMap to which the expression should be added
        pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
        Returns:
        the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression

      • copy

        public Expression copy()
        Copy an expression. This makes a deep copy.
        Overrides:
        copy in class SystemFunction
        Returns:
        the copy of the original expression

      • equals

        public boolean equals​(java.lang.Object o)
        Determine whether two expressions are equivalent
        Overrides:
        equals in class SystemFunction

      • iterate

        public SequenceIterator iterate​(XPathContext context)
                         throws XPathException
        Enumerate the results of the expression
        Overrides:
        iterate in class Expression
        Parameters:
        context - supplies the context for evaluation
        Returns:
        a SequenceIterator that can be used to iterate over the result of the expression
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression