Class ForExpression

    • Constructor Detail

      • ForExpression

        public ForExpression()
    • Method Detail

      • setPositionVariable

        public void setPositionVariable​(RangeVariableDeclaration decl)
        Set the reference to the position variable (XQuery only)
      • getPositionVariableNameCode

        public int getPositionVariableNameCode()
      • setAction

        public void setAction​(Expression action)
        Description copied from class: Assignation
        Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression
        Overrides:
        setAction in class Assignation
        Parameters:
        action - the expression that occurs after the "return" keyword of a "for" expression, the "satisfies" keyword of "some/every", or the ":=" operator of a "let" expression.

        This method must be called after calling setVariableDeclaration()

      • setSlotNumber

        public void setSlotNumber​(int nr)
        Set the slot number for the range variable
        Overrides:
        setSlotNumber in class Assignation
      • getRequiredSlots

        public int getRequiredSlots()
        Get the number of slots required. Normally 1, except for a FOR expression with an AT clause, where it is 2.
        Overrides:
        getRequiredSlots in class Assignation
      • typeCheck

        public Expression typeCheck​(StaticContext env,
                                    ItemType contextItemType)
                             throws XPathException
        Type-check the expression
        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
      • optimize

        public Expression optimize​(Optimizer opt,
                                   StaticContext env,
                                   ItemType contextItemType)
                            throws XPathException
        Optimize the expression
        Parameters:
        opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
        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 if appropriate to optimize execution
        Throws:
        StaticError - if an error is discovered during this phase (typically a type error)
        XPathException
      • markTailFunctionCalls

        public boolean markTailFunctionCalls​(int nameCode,
                                             int arity)
        Mark tail function calls: only possible if the for expression iterates zero or one times. (This arises in XSLT/XPath, which does not have a LET expression, so FOR gets used instead)
        Overrides:
        markTailFunctionCalls in class ComputedExpression
        Returns:
        true if a tail recursive call was found and if this call accounts for the whole of the value.
      • extendBindingList

        protected Binding[] extendBindingList​(Binding[] in)
        Extend an array of variable bindings to include the binding(s) defined in this expression
        Overrides:
        extendBindingList in class Assignation
      • getImplementationMethod

        public int getImplementationMethod()
        An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided. This implementation provides both iterate() and process() methods natively.
        Specified by:
        getImplementationMethod in interface Expression
        Overrides:
        getImplementationMethod in class ComputedExpression
      • checkPermittedContents

        public void checkPermittedContents​(SchemaType parentType,
                                           StaticContext env,
                                           boolean whole)
                                    throws XPathException
        Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type. It's always OK to say yes, since the check will be repeated at run-time. The process of checking element and attribute constructors against the content model of a complex type also registers the type of content expected of those constructors, so the static validation can continue recursively.
        Specified by:
        checkPermittedContents in interface Expression
        Overrides:
        checkPermittedContents in class ComputedExpression
        Parameters:
        parentType - The schema type
        env - the static context
        whole - true if this expression is expected to make the whole content of the type, false if it is expected to make up only a part
        Throws:
        XPathException - if the expression doesn't match the required content type
      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the data type of the items returned by the expression, if possible
        Parameters:
        th -
        Returns:
        one of the values Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)
      • display

        public void display​(int level,
                            java.io.PrintStream out,
                            Configuration config)
        Diagnostic print of expression structure
        Parameters:
        level - indentation level for this expression
        out - Output destination
      • getConstructType

        protected int getConstructType()
        Get the type of this expression for use in tracing and diagnostics
        Overrides:
        getConstructType in class ComputedExpression
        Returns:
        the type of expression, as enumerated in class Location