net.sf.saxon.expr.sort

Class GroupByIterator.ManualGroupByIterator

java.lang.Object

net.sf.saxon.tree.iter.ManualIterator

com.saxonica.ee.stream.ManualGroupIterator

net.sf.saxon.expr.sort.GroupByIterator.ManualGroupByIterator

All Implemented Interfaces:

LastPositionFinder, GroupIterator, FocusIterator, SequenceIterator, GroundedIterator, LookaheadIterator, ReversibleIterator, UnfailingIterator

Enclosing class:

GroupByIterator

public class GroupByIterator.ManualGroupByIterator
extends ManualGroupIterator

Field Summary

Fields inherited from interface net.sf.saxon.om.SequenceIterator

ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Constructors

Constructor and Description
GroupByIterator.ManualGroupByIterator()

Method Summary

Methods

Modifier and Type	Method and Description
GroupByIterator.ManualGroupByIterator	getAnother() Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
AtomicSequence	getCurrentGroupingKey() Get the grouping key of the current group
int	getLength() Get the position of the last item in the sequence
SequenceIterator	iterateCurrentGroup() Get an iterator over the members of the current group, in population order.

Methods inherited from class com.saxonica.ee.stream.ManualGroupIterator

getSnapShot, hasCurrentGroup, hasCurrentGroupingKey, setCurrentGroup, setCurrentGroupingKey

Methods inherited from class net.sf.saxon.tree.iter.ManualIterator

close, current, getProperties, getReverseIterator, hasNext, incrementPosition, materialize, next, position, setContextItem, setLastPositionFinder, setPosition

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.SequenceIterator

close, getProperties, next

Constructor Detail

GroupByIterator.ManualGroupByIterator

public GroupByIterator.ManualGroupByIterator()

Method Detail

iterateCurrentGroup

public SequenceIterator iterateCurrentGroup()
                                     throws XPathException

Description copied from interface: GroupIterator

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.

Specified by:

iterateCurrentGroup in interface GroupIterator

Overrides:

iterateCurrentGroup in class ManualGroupIterator

Returns:

an iterator over all the members of the current group, in population order.

Throws:

XPathException - if a dynamic error occurs

getCurrentGroupingKey

public AtomicSequence getCurrentGroupingKey()

Description copied from interface: GroupIterator

Get the grouping key of the current group

Specified by:

getCurrentGroupingKey in interface GroupIterator

Overrides:

getCurrentGroupingKey in class ManualGroupIterator

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

getAnother

public GroupByIterator.ManualGroupByIterator getAnother()

Description copied from interface: FocusIterator

Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

This method allows access to all the items in the sequence without disturbing the current position of the iterator. Internally, its main use is in evaluating the last() function.

This method does not change the state of the iterator.

Some implementations of this method may regenerate the input sequence, creating new nodes with different identity from the original. This is not recommended, but is hard to prevent. This causes no problem for the primary usage of this method to support the last() function, but it has been known to cause trouble in other situations.

Specified by:

getAnother in interface FocusIterator

Specified by:

getAnother in interface SequenceIterator

Specified by:

getAnother in interface UnfailingIterator

Overrides:

getAnother in class ManualIterator

Returns:

a SequenceIterator that iterates over the same items, positioned before the first item

getLength

public int getLength()
              throws XPathException

Description copied from interface: FocusIterator

Get the position of the last item in the sequence

Specified by:

getLength in interface LastPositionFinder

Specified by:

getLength in interface FocusIterator

Overrides:

getLength in class ManualIterator

Returns:

the position of the last item

Throws:

XPathException - if a failure occurs reading the sequence