net.sf.saxon.om
Interface SequenceIterator

All Known Subinterfaces:
AtomizableIterator, AxisIterator, GroundedIterator, GroupIterator, LastPositionFinder, LookaheadIterator, ReversibleIterator
All Known Implementing Classes:
AppendIterator, ArrayIterator, AxisIteratorImpl, DifferenceEnumeration, DistinctValues.DistinctIterator, DocumentOrderIterator, EmptyIterator, FilterIterator, GroupAdjacentIterator, GroupByIterator, GroupEndingIterator, GroupStartingIterator, Insert.InsertIterator, IntersectionEnumeration, ListIterator, MappingIterator, MemoClosure.ProgressiveIterator, NamespaceIterator, PositionIterator, PrependIterator, RangeExpression.RangeIterator, RegexIterator, ReverseArrayIterator, SingletonIterator, SortedGroupIterator, SortedIterator, StringTokenIterator, StringValue.CharacterIterator, TailExpression.TailIterator, Tokenize.TokenIterator, Trace.TracingIterator, UnionEnumeration

public interface SequenceIterator

A SequenceIterator is used to iterate over any XPath 2 sequence (of values or nodes). To get the next item in a sequence, call next(); if this returns null, you've reached the end of the sequence.

A SequenceIterator keeps track of the current Item and the current position. The objects returned by the SequenceIterator will always be either nodes (class NodeInfo) or singleton values (class AtomicValue): these are represented collectively by the interface Item.


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.
 

Method Detail

next

public Item next()
          throws XPathException
Get the next item in the sequence.

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()
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().

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()
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.

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

getAnother

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

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