net.sf.saxon.expr.flwor
Class TuplePull
java.lang.Object
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)
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 |
TuplePull
public TuplePull()
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.