Class AtomicSequenceConverter

    • Constructor Detail

      • AtomicSequenceConverter

        public AtomicSequenceConverter​(Expression sequence,
                                       PlainType requiredItemType,
                                       boolean allConverted)
        Constructor
        Parameters:
        sequence - this must be a sequence of atomic values. This is not checked; a ClassCastException will occur if the precondition is not satisfied.
        requiredItemType - the item type to which all items in the sequence should be converted, using the rules for "cast as".
    • Method Detail

      • makeUntypedSequenceConverter

        public static AtomicSequenceConverter makeUntypedSequenceConverter​(Configuration config,
                                                                           Expression operand,
                                                                           PlainType requiredItemType)
                                                                    throws XPathException
        Create an AtomicSequenceConverter that converts all untypedAtomic values in the input sequence to a specified target type, while leaving items other than untypedAtomic unchanged
        Parameters:
        config - the Saxon configuration
        operand - the expression that delivers the input sequence
        requiredItemType - the type to which untypedAtomic values should be cast, which must either be an atomic type or a "plain" union type
        Returns:
        an AtomicSequenceConverter that performs the required conversion
        Throws:
        XPathException
      • allocateConverter

        public void allocateConverter​(Configuration config)
      • getConverter

        public Converter getConverter()
        Get the converter used to convert the items in the sequence
        Returns:
        the converter. Note that a converter is always allocated during the typeCheck() phase, even if the source type is not known.
      • setConverter

        public void setConverter​(Converter converter)
      • isAllItemsConverted

        public boolean isAllItemsConverted()
        Ask if all items in the input are converted to the target type
      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                                    ExpressionVisitor.ContextItemType contextItemType)
                             throws XPathException
        Type-check the expression
        Overrides:
        typeCheck in class UnaryExpression
        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)
      • optimize

        public Expression optimize​(ExpressionVisitor visitor,
                                   ExpressionVisitor.ContextItemType contextItemType)
                            throws XPathException
        Perform optimisation of an expression and its subexpressions.
        Overrides:
        optimize in class UnaryExpression
        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)
      • copy

        public Expression copy()
        Copy an expression. This makes a deep copy.
        Specified by:
        copy in class Expression
        Returns:
        the copy of the original expression
      • iterate

        public SequenceIterator iterate​(XPathContext context)
                                 throws XPathException
        Iterate over the sequence of values
        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
      • evaluateItem

        public Item evaluateItem​(XPathContext context)
                          throws XPathException
        Evaluate as an Item. This should only be called if the AtomicSequenceConverter has cardinality zero-or-one
        Overrides:
        evaluateItem in class Expression
        Parameters:
        context - 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
      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the data type of the items returned by the expression, if possible
        Overrides:
        getItemType in class UnaryExpression
        Parameters:
        th - the type hierarchy cache
        Returns:
        a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)
      • equals

        public boolean equals​(java.lang.Object other)
        Is this expression the same as another expression?
        Overrides:
        equals in class UnaryExpression
      • hashCode

        public int hashCode()
        get 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:
        hashCode in class UnaryExpression
      • explain

        public void explain​(ExpressionPresenter destination)
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Overrides:
        explain in class UnaryExpression
        Parameters:
        destination - the expression presenter used to display the structure