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.

Constructor Summary

WhereClausePull(TuplePull base, Expression predicate)

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
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

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