net.sf.saxon.expr.flwor

Class ForClausePull

java.lang.Object

net.sf.saxon.expr.flwor.TuplePull

net.sf.saxon.expr.flwor.ForClausePull

Direct Known Subclasses:

ForClauseOuterPull, ForMemberClausePull

public class ForClausePull
extends TuplePull

This class implements the changes to the tuple stream effected by a "for" clause in a FLWOR expression

Field Summary

Fields

Modifier and Type	Field and Description
protected TuplePull	base
protected FocusIterator	currentIteration
protected ForClause	forClause

Constructor Summary

Constructors

Constructor and Description
ForClausePull(TuplePull base, ForClause forClause)

Method Summary

Modifier and Type	Method and 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
protected SequenceIterator	getIterator(XPathContext context) Get an iterator over the items or members in the target collection.
boolean	nextTuple(XPathContext context) Move on to the next tuple.
protected GroundedValue	variableValue(Item item) Get the value to be bound to the iteration variable

Methods inherited from class java.lang.Object

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

Field Detail

base

protected TuplePull base

forClause

protected ForClause forClause

currentIteration

protected FocusIterator currentIteration

Constructor Detail

ForClausePull

public ForClausePull(TuplePull base,
                     ForClause forClause)

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 - if any error occurs

getIterator

protected SequenceIterator getIterator(XPathContext context)
                                throws XPathException

Get an iterator over the items or members in the target collection.

Parameters:

context - dynamic evaluation context

Returns:

for a simple "for $x" clause, the sequence of items to which $x will be bound. For a "for member ¢x" clause, the sequence of array members, each wrapped as an object value

Throws:

XPathException - if evaluation fails

variableValue

protected GroundedValue variableValue(Item item)

Get the value to be bound to the iteration variable

Parameters:

item - the value returned by the sequence iterator

Returns:

the value to be assigned to the iteration variable

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