Package net.sf.saxon.expr.flwor

Class WhereClausePull

java.lang.Object

net.sf.saxon.expr.flwor.TuplePull

net.sf.saxon.expr.flwor.WhereClausePull

public class WhereClausePull
extends TuplePull

This class represents the tuple stream delivered as the output of a where clause in a FLWOR expression: that is, it returns all the tuples in its input stream that satisfy a specified predicate. It does not change the values of any variables in the tuple stream.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) TuplePull	base
(package private) Expression	predicate

Constructor Summary

Constructors

Constructor	Description
WhereClausePull(TuplePull base, Expression predicate)

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

Field Detail

base

TuplePull base

predicate

Expression predicate

Constructor Detail

WhereClausePull

public WhereClausePull(TuplePull base,
                       Expression predicate)

Method Detail

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

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