Class IntersectionEnumeration

  • All Implemented Interfaces:
    SequenceIterator

    public class IntersectionEnumeration
    extends java.lang.Object
    implements SequenceIterator
    An enumeration representing a nodeset that is an intersection of two other NodeSets. This implements the XPath 2.0 operator "intersect".
    • Constructor Detail

      • IntersectionEnumeration

        public IntersectionEnumeration​(SequenceIterator p1,
                                       SequenceIterator p2,
                                       NodeOrderComparer comparer)
                                throws XPathException
        Form an enumeration of the intersection of the nodes in two nodesets
        Parameters:
        p1 - the first operand: must be in document order
        p2 - the second operand: must be in document order
        comparer - Comparer to be used for putting nodes in document order
        Throws:
        XPathException
    • Method Detail

      • next

        public Item next()
                  throws XPathException
        Description copied from interface: SequenceIterator
        Get the next item in the sequence. This method changes the state of the iterator, in particular it affects the result of subsequent calls of position() and current().
        Specified by:
        next in interface SequenceIterator
        Returns:
        the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.
        Throws:
        XPathException - if an error occurs retrieving the next item
      • current

        public Item current()
        Description copied from interface: SequenceIterator
        Get the current value in the sequence (the one returned by the most recent call on next()). This will be null before the first call of next(). This method does not change the state of the iterator.
        Specified by:
        current in interface SequenceIterator
        Returns:
        the current item, the one most recently returned by a call on next(). Returns null if next() has not been called, or if the end of the sequence has been reached.
      • position

        public int position()
        Description copied from interface: SequenceIterator
        Get the current position. This will usually be zero before the first call on next(), otherwise it will be the number of times that next() has been called. Once next() has returned null, the preferred action is for subsequent calls on position() to return -1, but not all existing implementations follow this practice. (In particular, the EmptyIterator is stateless, and always returns 0 as the value of position(), whether or not next() has been called.)

        This method does not change the state of the iterator.

        Specified by:
        position in interface SequenceIterator
        Returns:
        the current position, the position of the item returned by the most recent call of next(). This is 1 after next() has been successfully called once, 2 after it has been called twice, and so on. If next() has never been called, the method returns zero. If the end of the sequence has been reached, the value returned will always be <= 0; the preferred value is -1.
      • getAnother

        public SequenceIterator getAnother()
                                    throws XPathException
        Description copied from interface: SequenceIterator
        Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

        This method allows access to all the items in the sequence without disturbing the current position of the iterator. Internally, its main use is in evaluating the last() function.

        This method does not change the state of the iterator.

        Specified by:
        getAnother in interface SequenceIterator
        Returns:
        a SequenceIterator that iterates over the same items, positioned before the first item
        Throws:
        XPathException - if any error occurs