net.sf.saxon.expr.flwor
Class TuplePull

java.lang.Object
  extended by net.sf.saxon.expr.flwor.TuplePull
Direct Known Subclasses:
CountClausePull, ForClausePull, GroupByClausePull, LetClausePull, OrderByClausePull, SingularityPull, WhereClausePull, WindowClausePull

public abstract class TuplePull
extends Object

Abtract class representing a tuple stream (used to evaluate a FLWOR expression) in pull mode (where the consumer of tuples activates the provider of those tuples)


Constructor Summary
TuplePull()
           
 
Method Summary
 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
abstract  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 Detail

TuplePull

public TuplePull()
Method Detail

nextTuple

public abstract 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

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



Copyright (c) 2004-2011 Saxonica Limited. All rights reserved.