Package net.sf.saxon.expr.sort

Class SortedGroupIterator

java.lang.Object

net.sf.saxon.expr.sort.SortedIterator

net.sf.saxon.expr.sort.SortedGroupIterator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, LastPositionFinder, GroupIterator, SequenceIterator, LookaheadIterator

public class SortedGroupIterator
extends SortedIterator
implements GroupIterator

A SortedGroupIterator is a modified SortedIterator. It sorts a sequence of groups, and is itself a GroupIterator. The modifications retain extra information about the items being sorted. The items are each the leading item of a group, and as well as the item itself, the iterator preserves information about the group: specifically, an iterator over the items in the group, and the value of the grouping key (if any).

Field Summary

Fields inherited from class net.sf.saxon.expr.sort.SortedIterator

comparators, context, count, position, sortKeyEvaluator, values

Constructor Summary

Constructors

Constructor	Description
SortedGroupIterator(XPathContext context, GroupIterator base, SortKeyEvaluator sortKeyEvaluator, AtomicComparer[] comparators)

Method Summary

Modifier and Type	Method	Description
protected void	buildArray()	Override the method that builds the array of values and sort keys.
GroundedValue	currentGroup()	Get a sequence containing the members of the current group, in population order.
AtomicSequence	getCurrentGroupingKey()	Get the grouping key of the current group
ManualGroupIterator	getSnapShot(XPathContext context)	Get a pseudo-iterator which represents a snapshot of this sequence at the current position

Methods inherited from class net.sf.saxon.expr.sort.SortedIterator

getBaseIterator, getLength, hasNext, next, setHostLanguage, supportsGetLength, supportsHasNext

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, next

Constructor Detail

SortedGroupIterator

public SortedGroupIterator(XPathContext context,
                           GroupIterator base,
                           SortKeyEvaluator sortKeyEvaluator,
                           AtomicComparer[] comparators)

Method Detail

buildArray

protected void buildArray()
                   throws XPathException

Override the method that builds the array of values and sort keys.

Overrides:

buildArray in class SortedIterator

Throws:

XPathException - in the event of a dynamic error

getCurrentGroupingKey

public AtomicSequence getCurrentGroupingKey()

Description copied from interface: GroupIterator

Get the grouping key of the current group

Specified by:

getCurrentGroupingKey in interface GroupIterator

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

public GroundedValue currentGroup()
                           throws XPathException

Description copied from interface: GroupIterator

Get a sequence containing the members of the current group, in population order. This may be a MemoSequence rather than a grounded value

Specified by:

currentGroup in interface GroupIterator

Returns:

a sequence containing all the members of the current group, in population order.

Throws:

XPathException - if a dynamic error occurs

getSnapShot

public ManualGroupIterator getSnapShot(XPathContext context)

Description copied from interface: GroupIterator

Get a pseudo-iterator which represents a snapshot of this sequence at the current position

Specified by:

getSnapShot in interface GroupIterator

Parameters:

context - the XPath context

Returns:

the snapshot sequence