Class VariableReference

    • Field Detail

      • constantValue

        Value constantValue
      • displayName

        transient java.lang.String displayName
    • Constructor Detail

      • VariableReference

        public VariableReference()
      • VariableReference

        public VariableReference​(VariableDeclaration declaration)
        Constructor
        Parameters:
        declaration - the variable declaration to which this variable refers
    • Method Detail

      • copy

        public VariableReference copy()
        Create a clone copy of this VariableReference
      • setStaticType

        public void setStaticType​(SequenceType type,
                                  Value value,
                                  int properties)
        Set static type. This is a callback from the variable declaration object. As well as supplying the static type, it may also supply a compile-time value for the variable. As well as the type information, other static properties of the value are supplied: for example, whether the value is an ordered node-set.
        Specified by:
        setStaticType in interface BindingReference
      • typeCheck

        public Expression typeCheck​(StaticContext env,
                                    ItemType contextItemType)
                             throws XPathException
        Type-check the expression. At this stage details of the static type must be known. If the variable has a compile-time value, this is substituted for the variable reference
        Specified by:
        typeCheck in interface 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
        Type-check the expression. At this stage details of the static type must be known. If the variable has a compile-time value, this is substituted for the variable reference
        Specified by:
        optimize in interface 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
      • fixup

        public void fixup​(Binding binding)
        Fix up this variable reference to a Binding object, which enables the value of the variable to be located at run-time.
        Specified by:
        fixup in interface BindingReference
      • refineVariableReference

        public void refineVariableReference()
        Replace this VariableReference where appropriate by a more efficient implementation. This can only be done after all slot numbers are allocated. The efficiency is gained by binding the VariableReference directly to a local or global slot, rather than going via the Binding object
      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the data type of the expression, if possible
        Specified by:
        getItemType in interface Expression
        Parameters:
        th -
        Returns:
        the type of the variable, if this can be determined statically; otherwise Type.ITEM (meaning not known in advance)
      • equals

        public boolean equals​(java.lang.Object other)
        Test if this expression is the same as another expression. (Note, we only compare expressions that have the same static and dynamic context).
        Overrides:
        equals in class java.lang.Object
      • hashCode

        public int hashCode()
        get HashCode for comparing two expressions
        Overrides:
        hashCode in class java.lang.Object
      • getIntrinsicDependencies

        public int getIntrinsicDependencies()
        Description copied from class: ComputedExpression
        Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".
        Overrides:
        getIntrinsicDependencies in class ComputedExpression
        Returns:
        a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
      • promote

        public Expression promote​(PromotionOffer offer)
                           throws XPathException
        Promote this expression if possible
        Specified by:
        promote in interface Expression
        Overrides:
        promote in class ComputedExpression
        Parameters:
        offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
        Returns:
        if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
        Throws:
        XPathException - if any error is detected
      • 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 all three methods natively.
        Specified by:
        getImplementationMethod in interface Expression
        Overrides:
        getImplementationMethod in class ComputedExpression
      • evaluateItem

        public Item evaluateItem​(XPathContext c)
                          throws XPathException
        Description copied from class: ComputedExpression
        Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.
        Specified by:
        evaluateItem in interface Expression
        Overrides:
        evaluateItem in class ComputedExpression
        Parameters:
        c - The context in which the expression is to be evaluated
        Returns:
        the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression
      • getBinding

        public Binding getBinding()
        Get the object bound to the variable
      • display

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