GroupIterator

All Superinterfaces:

java.lang.AutoCloseable, java.io.Closeable, SequenceIterator

All Known Implementing Classes:

GroupAdjacentIterator, GroupBreakingIterator, GroupByIterator, GroupByIterator.ManualGroupByIterator, GroupEndingIterator, GroupMatchingIterator, GroupStartingIterator, ManualGroupIterator, MergeGroupingIterator, MergeGroupingIterator.ManualMergeGroupingIterator, 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

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`AtomicSequence`	`getCurrentGroupingKey()`	Get the grouping key of the current group
`ManualGroupIterator`	`getSnapShot(XPathContext context)`	Get a sequence which is a snapshot of this sequence at the current position
`SequenceIterator`	`iterateCurrentGroup()`	Get an iterator over the members of the current group, in population order.

Methods inherited from interface net.sf.saxon.om.SequenceIterator
close, discharge, next

- Method Detail
  - 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
  - iterateCurrentGroup
```
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.
    
    Throws:
    
    XPathException - if a dynamic error occurs
  - getSnapShot
```
ManualGroupIterator getSnapShot(XPathContext context)
                         throws XPathException
```
    Get a sequence which is a snapshot of this sequence at the current position
    
    Parameters:
    
    context - the XPath context
    
    Returns:
    
    the snapshot sequence
    
    Throws:
    
    XPathException - if any error occurs