net.sf.saxon.expr
Class DifferenceEnumeration

java.lang.Object
  extended bynet.sf.saxon.expr.DifferenceEnumeration
All Implemented Interfaces:
SequenceIterator

public class DifferenceEnumeration
extends java.lang.Object
implements SequenceIterator

An enumeration representing a nodeset that is teh difference of two other NodeSets. There is an "except" operator in XPath 2.0 to create such an expression.


Constructor Summary
DifferenceEnumeration(SequenceIterator p1, SequenceIterator p2, NodeOrderComparer comparer)
          Form an enumeration of the difference of two nodesets, that is, the nodes that are in p1 and that are not in p2.
 
Method Summary
 Item current()
          Get the current value in the sequence (the one returned by the most recent call on next()).
 SequenceIterator getAnother()
          Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
 Item next()
          Get the next item in the sequence.
 int position()
          Get the current position.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DifferenceEnumeration

public DifferenceEnumeration(SequenceIterator p1,
                             SequenceIterator p2,
                             NodeOrderComparer comparer)
                      throws XPathException
Form an enumeration of the difference of two nodesets, that is, the nodes that are in p1 and that are not in p2.

Parameters:
p1 - the first operand
p2 - the second operand
comparer - the comparer
Method Detail

next

public Item next()
          throws XPathException
Description copied from interface: SequenceIterator
Get the next item in the sequence.

Specified by:
next in interface SequenceIterator
Returns:
the next item, or null if there are no more items.
Throws:
XPathException - if an error occurs retrieving the next item

current

public Item current()
Description copied from interface: SequenceIterator
Get the current value in the sequence (the one returned by the most recent call on next()). This will be null before the first call of next().

Specified by:
current in interface SequenceIterator
Returns:
the current item, the one most recently returned by a call on next(); or null, if next() has not been called, or if the end of the sequence has been reached.

position

public int position()
Description copied from interface: SequenceIterator
Get the current position. This will be zero before the first call on next(), otherwise it will be the number of times that next() has been called.

Specified by:
position in interface SequenceIterator
Returns:
the current position, the position of the item returned by the most recent call of next()

getAnother

public SequenceIterator getAnother()
                            throws XPathException
Description copied from interface: SequenceIterator
Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

Specified by:
getAnother in interface SequenceIterator
Returns:
a SequenceIterator that iterates over the same items, positioned before the first item
Throws:
XPathException - if any error occurs