Class VennExpression

    • Constructor Detail

      • VennExpression

        public VennExpression​(Expression p1,
                              int op,
                              Expression p2)
        Constructor
        Parameters:
        p1 - the left-hand operand
        op - the operator (union, intersection, or difference)
        p2 - the right-hand operand
    • Method Detail

      • simplify

        public Expression simplify()
                            throws XPathException
        Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation simplifies its operands.
        Overrides:
        simplify in class Expression
        Returns:
        the simplified expression (or the original if unchanged, or if modified in-situ)
        Throws:
        XPathException - if an error is discovered during expression rewriting
      • getExpressionName

        public java.lang.String getExpressionName()
        Get a name identifying the kind of expression, in terms meaningful to a user.
        Overrides:
        getExpressionName in class Expression
        Returns:
        a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.
      • getItemType

        public final ItemType getItemType()
        Determine the data type of the items returned by this expression
        Specified by:
        getItemType in class Expression
        Returns:
        the data type
      • getStaticUType

        public UType getStaticUType​(UType contextItemType)
        Get the static type of the expression as a UType, following precisely the type inference rules defined in the XSLT 3.0 specification.
        Overrides:
        getStaticUType in class Expression
        Parameters:
        contextItemType - the static type of the context item
        Returns:
        the static item type of the expression according to the XSLT 3.0 defined rules
      • computeSpecialProperties

        protected 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 property bit is set, it is true, but if it is unset, the value is unknown.
        Overrides:
        computeSpecialProperties in class BinaryExpression
        Returns:
        StaticProperty.NO_NODES_NEWLY_CREATED. This is overridden for some subclasses.
      • gatherComponents

        public void gatherComponents​(int operator,
                                     java.util.Set<Expression> set)
        Gather the component operands of a union or intersect expression
        Parameters:
        operator - union or intersect
        set - the set into which the components are to be gathered. If the operator is union, this follows the tree gathering all operands of union expressions. Ditto, mutatis mutandis, for intersect expressions.
      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                                    ContextItemStaticInfo contextInfo)
                             throws XPathException
        Type-check the expression
        Overrides:
        typeCheck in class BinaryExpression
        Parameters:
        visitor - an expression visitor
        contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.
        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)
      • optimize

        public Expression optimize​(ExpressionVisitor visitor,
                                   ContextItemStaticInfo contextItemType)
                            throws XPathException
        Perform optimisation of an expression and its subexpressions.

        This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

        Overrides:
        optimize in class BinaryExpression
        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 if appropriate to optimize execution
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • unordered

        public Expression unordered​(boolean retainAllNodes,
                                    boolean forStreaming)
        Replace this expression by an expression that returns the same result but without regard to order
        Overrides:
        unordered in class Expression
        Parameters:
        retainAllNodes - true if all nodes in the result must be retained; false if duplicates can be eliminated
        forStreaming - set to true if optimizing for streaming
        Returns:
        an expression that delivers the same nodes in a more convenient order
      • copy

        public Expression copy​(RebindingMap rebindings)
        Copy an expression. This makes a deep copy.
        Specified by:
        copy in class Expression
        Parameters:
        rebindings - variables that need to be rebound
        Returns:
        the copy of the original expression
      • getOperandRole

        protected OperandRole getOperandRole​(int arg)
        Get the operand role (applies to both operands)
        Overrides:
        getOperandRole in class BinaryExpression
        Parameters:
        arg - which argument: 0 for the lhs, 1 for the rhs
        Returns:
        the operand role
      • equals

        public boolean equals​(java.lang.Object other)
        Is this expression the same as another expression?
        Overrides:
        equals in class BinaryExpression
        Parameters:
        other - the other operand; the result is false if this is not an Expression
        Returns:
        true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.
      • computeHashCode

        protected int computeHashCode()
        Description copied from class: BinaryExpression
        Get a hashCode for comparing two expressions. Note that this hashcode gives the same result for (A op B) and for (B op A), whether or not the operator is commutative.
        Overrides:
        computeHashCode in class BinaryExpression
        Returns:
        a computed hash code
      • tag

        protected java.lang.String tag()
        Get the element name used to identify this expression in exported expression format
        Overrides:
        tag in class BinaryExpression
        Returns:
        the element name used to identify this expression
      • iterate

        public SequenceIterator iterate​(XPathContext c)
                                 throws XPathException
        Iterate over the value of the expression. The result will always be sorted in document order, with duplicates eliminated
        Overrides:
        iterate in class Expression
        Parameters:
        c - The context for evaluation
        Returns:
        a SequenceIterator representing the union of the two operands
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression
      • effectiveBooleanValue

        public boolean effectiveBooleanValue​(XPathContext context)
                                      throws XPathException
        Get the effective boolean value. In the case of a union expression, this is reduced to an OR expression, for efficiency
        Overrides:
        effectiveBooleanValue in class Expression
        Parameters:
        context - The context in which the expression is to be evaluated
        Returns:
        the effective boolean value
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression
      • getStreamerName

        public java.lang.String getStreamerName()
        Get the (partial) name of a class that supports streaming of this kind of expression
        Overrides:
        getStreamerName in class Expression
        Returns:
        the partial name of a class that can be instantiated to provide streaming support in Saxon-EE, or null if there is no such class