Class MatchingIterator

  • All Implemented Interfaces:
    java.lang.Cloneable, DTMAxisIterator

    public final class MatchingIterator
    extends DTMAxisIteratorBase
    This is a special kind of iterator that takes a source iterator and a node N. If initialized with a node M (the parent of N) it computes the position of N amongst the children of M. This position can be obtained by calling getPosition(). It is an iterator even though next() will never be called. It is used to match patterns with a single predicate like: BOOK[position() = last()] In this example, the source iterator will return elements of type BOOK, a call to position() will return the position of N. Notice that because of the way the pattern matching is implemented, N will always be a node in the source since (i) it is a BOOK or the test sequence would not be considered and (ii) the source iterator is initialized with M which is the parent of N. Also, and still in this example, a call to last() will return the number of elements in the source (i.e. the number of BOOKs).
    Author:
    Jacek Ambroziak, Santiago Pericas-Geertsen
    • Constructor Detail

      • MatchingIterator

        public MatchingIterator​(int match,
                                DTMAxisIterator source)
    • Method Detail

      • 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.
      • 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.
      • getLast

        public int getLast()
        Description copied from class: DTMAxisIteratorBase
        Returns the position of the last node within the iteration, as defined by XPath. In a forward iterator, I believe this equals the number of nodes which this iterator will yield. In a reverse iterator, I believe it should return 1 (since the "last" is the first produced.) This may be an expensive operation when called the first time, since it may have to iterate through a large part of the document to produce its answer.
        Specified by:
        getLast in interface DTMAxisIterator
        Overrides:
        getLast in class DTMAxisIteratorBase
        Returns:
        The number of nodes in this iterator (forward) or 1 (reverse).
      • 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().