Package net.sf.saxon.expr.flwor

Class GroupByClausePull

java.lang.Object

net.sf.saxon.expr.flwor.TuplePull

net.sf.saxon.expr.flwor.GroupByClausePull

public class GroupByClausePull
extends TuplePull

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
GroupByClausePull(TuplePull base, GroupByClause groupBy, XPathContext context)

Method Summary

Modifier and Type	Method	Description
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
boolean	nextTuple(XPathContext context)	Move on to the next tuple.

Methods inherited from class java.lang.Object

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

Constructor Details

GroupByClausePull

public GroupByClausePull(TuplePull base,
 GroupByClause groupBy,
 XPathContext context)

Method Details

nextTuple

public boolean nextTuple(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:

nextTuple in class TuplePull

Parameters:

context - the dynamic evaluation context

Returns:

true if another tuple has been generated; false if the tuple stream is exhausted. If the method returns false, the values of the local variables corresponding to this tuple stream are undefined.

Throws:

XPathException - if any error occurs

close

public 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

Overrides:

close in class TuplePull