net.sf.saxon.expr.sort
Class GroupBySingletonIterator

java.lang.Object
  extended by net.sf.saxon.expr.sort.GroupByIterator
      extended by net.sf.saxon.expr.sort.GroupBySingletonIterator
All Implemented Interfaces:
LastPositionFinder, GroupIterator, SequenceIterator, LookaheadIterator

public class GroupBySingletonIterator
extends GroupByIterator

A variant of the GroupByIterator used for XQuery 1.1 grouping, where the grouping key is either a single atomic value or an empty sequence, and an empty sequence compares equal to an empty sequence.


Field Summary
 
Fields inherited from class net.sf.saxon.expr.sort.GroupByIterator
comparer, groupKeys, groups, keyExpression
 
Fields inherited from interface net.sf.saxon.om.SequenceIterator
GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
 
Constructor Summary
GroupBySingletonIterator(SequenceIterator population, Expression keyExpression, XPathContext keyContext, StringCollator collator)
          Create a GroupByIterator
 
Method Summary
protected  void processItem(HashMap<ComparisonKey,List<Item>> index, Item item, XPathContext c2)
          Process one item in the population
 
Methods inherited from class net.sf.saxon.expr.sort.GroupByIterator
close, current, getAnother, getCurrentGroup, getCurrentGroupingKey, getLastPosition, getProperties, hasNext, iterateCurrentGroup, next, position
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

GroupBySingletonIterator

public GroupBySingletonIterator(SequenceIterator population,
                                Expression keyExpression,
                                XPathContext keyContext,
                                StringCollator collator)
                         throws XPathException
Create a GroupByIterator

Parameters:
population - iterator over the population to be grouped
keyExpression - the expression used to calculate the grouping key
keyContext - dynamic context for calculating the grouping key
collator - Collation to be used for comparing grouping keys
Throws:
XPathException
Method Detail

processItem

protected void processItem(HashMap<ComparisonKey,List<Item>> index,
                           Item item,
                           XPathContext c2)
                    throws XPathException
Process one item in the population

Overrides:
processItem in class GroupByIterator
Parameters:
index - the index of items
item - the item from the population to be processed
c2 - the XPath evaluation context
Throws:
XPathException


Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.