Class KeyFn

    • Constructor Detail

      • KeyFn

        public KeyFn()
    • Method Detail

      • typeCheck

        public Expression typeCheck​(StaticContext env,
                                    ItemType 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.
        Specified by:
        typeCheck in interface Expression
        Overrides:
        typeCheck in class FunctionCall
        Parameters:
        env - the static context of the expression
        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:
        StaticError - if an error is discovered during this phase (typically a type error)
        XPathException
      • internalKeyCall

        public static KeyFn internalKeyCall​(NamePool pool,
                                            int fingerprint,
                                            java.lang.String name,
                                            Expression value,
                                            Expression doc)
        Non-standard constructor to create an internal call on key() with a known key fingerprint
      • 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