Package net.sf.saxon.expr.flwor

Class GroupByClausePush

java.lang.Object

net.sf.saxon.expr.flwor.TuplePush

net.sf.saxon.expr.flwor.GroupByClausePush

public class GroupByClausePush
extends TuplePush

Represents the tuple stream delivered by an "group by" clause. This groups the tuple stream supplied as its input, and outputs a new set of tuples one per group of the input tuples. No groups are output until all the groups have been read.

Constructor Summary

Constructors

Constructor	Description
GroupByClausePush(Outputter outputter, TuplePush destination, GroupByClause groupBy, XPathContext context)

Method Summary

Modifier and Type	Method	Description
protected static void	addToGroup(Object key, GroupByClause.ObjectToBeGrouped objectToBeGrouped, List<GroupByClause.ObjectToBeGrouped> group, HashMap<Object,List<GroupByClause.ObjectToBeGrouped>> map)
protected static void	checkGroupingValues(Sequence[] groupingValues)
void	close()	Close the tuple stream, indicating that although not all tuples have been read, no further tuples are required and resources can be released
void	processTuple(XPathContext context)	Move on to the next tuple.

Methods inherited from class net.sf.saxon.expr.flwor.TuplePush

getOutputter

Methods inherited from class java.lang.Object

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

Constructor Details

GroupByClausePush

public GroupByClausePush(Outputter outputter,
 TuplePush destination,
 GroupByClause groupBy,
 XPathContext context)

Method Details

processTuple

public void processTuple(XPathContext context)
                  throws XPathException

Move on to the next tuple. Before returning, this method must set all the variables corresponding to the "returned" tuple in the local stack frame associated with the context object

Specified by:

processTuple in class TuplePush

Parameters:

context - the dynamic evaluation context

Throws:

XPathException - if a dynamic error occurs

addToGroup

protected static void addToGroup(Object key,
 GroupByClause.ObjectToBeGrouped objectToBeGrouped,
 List<GroupByClause.ObjectToBeGrouped> group,
 HashMap<Object,List<GroupByClause.ObjectToBeGrouped>> map)

checkGroupingValues

protected static void checkGroupingValues(Sequence[] groupingValues)
                                   throws XPathException

Throws:

XPathException

close

public void close()
           throws XPathException

Close the tuple stream, indicating that although not all tuples have been read, no further tuples are required and resources can be released

Overrides:

close in class TuplePush

Throws:

XPathException - if a dynamic error occurs