Class MultiValuedNodeHeapIterator

  • All Implemented Interfaces:
    java.lang.Cloneable, DTMAxisIterator
    Direct Known Subclasses:
    KeyIndex.KeyIndexIterator, UnionIterator

    public abstract class MultiValuedNodeHeapIterator
    extends DTMAxisIteratorBase

    MultiValuedNodeHeapIterator takes a set of multi-valued heap nodes and produces a merged NodeSet in document order with duplicates removed.

    Each multi-valued heap node (which might be a DTMAxisIterator, but that's not necessary) generates DTM node handles in document order. The class maintains the multi-valued heap nodes in a heap, not surprisingly, sorted by the next DTM node handle available form the heap node.

    After a DTM node is pulled from the heap node that's at the top of the heap, the heap node is advanced to the next DTM node handle it makes available, and the heap nature of the heap is restored to ensure the next DTM node handle pulled is next in document order overall.

    Author:
    Jacek Ambroziak, Santiago Pericas-Geertsen
    • Constructor Detail

      • MultiValuedNodeHeapIterator

        public MultiValuedNodeHeapIterator()
    • Method Detail

      • next

        public int next()
        Description copied from interface: DTMAxisIterator
        Get the next node in the iteration.
        Returns:
        The next node handle in the iteration, or END.
      • setStartNode

        public DTMAxisIterator setStartNode​(int node)
        Description copied from interface: DTMAxisIterator
        Set start to END should 'close' the iterator, i.e. subsequent call to next() should return END.
        Parameters:
        node - Sets the root of the iteration.
        Returns:
        A DTMAxisIterator set to the start of the iteration.
      • setMark

        public void setMark()
        Description copied from interface: DTMAxisIterator
        Remembers the current node for the next call to gotoMark().
      • gotoMark

        public void gotoMark()
        Description copied from interface: DTMAxisIterator
        Restores the current node remembered by setMark().