Package net.sf.saxon.expr.sort

Interface GroupIterator

All Superinterfaces:
AutoCloseable, Closeable, SequenceIterator
All Known Implementing Classes:
GroupAdjacentIterator, GroupBreakingIterator, GroupByIterator, GroupEndingIterator, GroupMatchingIterator, GroupStartingIterator, ManualGroupIterator, MergeGroupingIterator, SortedGroupIterator
public interface GroupIterator extends SequenceIterator
A GroupIterator is an iterator that iterates over a sequence of groups. The normal methods such as next() and current() always deliver the leading item of the group. Additional methods are available to get the grouping key for the current group (only applicable to group-by and group-adjacent), and to get all the members of the current group.

  • Method Details

    • getCurrentGroupingKey

      AtomicSequence getCurrentGroupingKey()
      Get the grouping key of the current group
      Returns:
      the current grouping key in the case of group-by or group-adjacent, or null in the case of group-starting-with and group-ending-with

    • currentGroup

      GroundedValue currentGroup() throws XPathException
      Get a sequence containing the members of the current group, in population order. This may be a MemoSequence rather than a grounded value
      Returns:
      a sequence containing all the members of the current group, in population order.
      Throws:
      XPathException - if a dynamic error occurs

    • getSnapShot

      ManualGroupIterator getSnapShot(XPathContext context) throws XPathException
      Get a pseudo-iterator which represents a snapshot of this sequence at the current position
      Parameters:
      context - the XPath context
      Returns:
      the snapshot sequence
      Throws:
      XPathException - if any error occurs