net.sf.saxon.expr.sort

Interface GroupIterator

All Superinterfaces:

SequenceIterator

All Known Implementing Classes:

GroupAdjacentIterator, GroupByIterator, GroupByIterator.ManualGroupByIterator, GroupEndingIterator, GroupMatchingIterator, GroupStartingIterator, ManualGroupIterator, MergeGroupingIterator, MergeGroupingIterator.ManualMergGroupingIterator, 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.

Field Summary

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Method Summary

Methods

Modifier and Type	Method and 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
boolean	hasCurrentGroup() Ask whether this iterator has a current group
boolean	hasCurrentGroupingKey() Ask whether this iterator has a current grouping key
SequenceIterator<? extends Item>	iterateCurrentGroup() Get an iterator over the members of the current group, in population order.
void	setGroupSlot(int groupSlot) Set a local variable slot to hold the value of the current group
void	setKeySlot(int keySlot) Set a local variable slot to hold the value of the current grouping key

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

close, current, getAnother, getProperties, next, position

Method Detail

setGroupSlot

void setGroupSlot(int groupSlot)

Set a local variable slot to hold the value of the current group

Parameters:

groupSlot - the stack frame position of the variable holding the current group

setKeySlot

void setKeySlot(int keySlot)

Set a local variable slot to hold the value of the current grouping key

Parameters:

keySlot - the stack frame position of the variable holding the current grouping key

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<? extends Item> 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

hasCurrentGroup

boolean hasCurrentGroup()

Ask whether this iterator has a current group

Returns:

false if the controlling xsl:for-each-group element binds a group variable, true if it delivers results using the current-group() function

hasCurrentGroupingKey

boolean hasCurrentGroupingKey()

Ask whether this iterator has a current grouping key

Returns:

false if the controlling xsl:for-each-group element binds a grouping-key variable, true if it delivers results using the current-grouping-key() function

getSnapShot

ManualGroupIterator getSnapShot(XPathContext context)
                                throws XPathException

Get a sequence which is a snapshot of this sequence at the current position

Throws:

XPathException