## net.sf.saxon.sort
Interface GroupIterator

All Superinterfaces:
  SequenceIterator

All Known Implementing Classes:
  GroupAdjacentIterator, GroupByIterator, GroupEndingIterator, GroupStartingIterator, 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 Summary
`AtomicValue` `getCurrentGroupingKey()` Get the grouping key of the current group
`SequenceIterator` `iterateCurrentGroup()` Get an iterator over the members of the current group, in population order.

Methods inherited from interface net.sf.saxon.om.SequenceIterator
`current, getAnother, next, position`

Method Detail

### getCurrentGroupingKey

    public AtomicValue 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

### iterateCurrentGroup

    public SequenceIterator iterateCurrentGroup()
                                         throws XPathException

  Get an iterator over the members of the current group, in population order. This must always be a clean iterator, that is, an iterator that starts at the first item of the group.

  Returns:
    an iterator over all the members of the current group, in population order.
    `XPathException`