Class DifferenceEnumeration

  • All Implemented Interfaces:, java.lang.AutoCloseable, SequenceIterator

    public class DifferenceEnumeration
    extends java.lang.Object
    implements SequenceIterator
    An enumeration representing a nodeset that is teh difference of two other NodeSets. There is an "except" operator in XPath 2.0 to create such an expression.
    • Constructor Detail

      • DifferenceEnumeration

        public DifferenceEnumeration​(SequenceIterator p1,
                                     SequenceIterator p2,
                                     ItemOrderComparer comparer)
                              throws XPathException
        Form an enumeration of the difference of two nodesets, that is, the nodes that are in p1 and that are not in p2.
        p1 - the first operand, with nodes delivered in document order
        p2 - the second operand, with nodes delivered in document order
        comparer - the comparer
        XPathException - if a failure occurs reading from either input sequence
    • Method Detail

      • next

        public NodeInfo next()
                      throws XPathException
        Description copied from interface: SequenceIterator
        Get the next item in the sequence. This method changes the state of the iterator.
        Specified by:
        next in interface SequenceIterator
        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.
        XPathException - if an error occurs retrieving the next item
      • close

        public void close()
        Description copied from interface: SequenceIterator
        Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

        For example, the iterator returned by the unparsed-text-lines() function has a close() method that causes the underlying input stream to be closed, whether or not the file has been read to completion.

        Closing an iterator is important when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.

        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface
        Specified by:
        close in interface SequenceIterator