Class DistinctValues.DistinctIterator

  • All Implemented Interfaces:
    SequenceIterator
    Enclosing class:
    DistinctValues

    public static class DistinctValues.DistinctIterator
    extends java.lang.Object
    implements SequenceIterator
    Iterator class to return the distinct values in a sequence
    • Constructor Detail

      • DistinctIterator

        public DistinctIterator​(SequenceIterator base,
                                AtomicComparer comparer)
        Create an iterator over the distinct values in a sequence
        Parameters:
        base - the input sequence. This must return atomic values only.
        comparer - The comparer used to obtain comparison keys from each value; these comparison keys are themselves compared using equals().
    • Method Detail

      • next

        public Item next()
                  throws XPathException
        Get the next item in the sequence.
        Specified by:
        next in interface SequenceIterator
        Returns:
        the next item, or null if there are no more items.
        Throws:
        XPathException - if an error occurs retrieving the next item
      • current

        public Item current()
        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().
        Specified by:
        current in interface SequenceIterator
        Returns:
        the current item, the one most recently returned by a call on next(); or null, if next() has not been called, or if the end of the sequence has been reached.
      • position

        public int position()
        Get the current position. This will be zero before the first call on next(), otherwise it will be the number of times that next() has been called.
        Specified by:
        position in interface SequenceIterator
        Returns:
        the current position, the position of the item returned by the most recent call of next()
      • 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.

        (Currently, closing an iterator is important only 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 SequenceIterator
      • getAnother

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