net.sf.saxon.expr

Interface LastPositionFinder

All Known Implementing Classes:

ARegexIterator, ArrayIterator, ArrayIterator.Of, ArrayIterator.OfNodes, AscendingRangeIterator, BigRangeIterator, DescendingRangeIterator, EmptyIterator, FocusTrackingIterator, GroupAdjacentIterator, GroupByIterator, GroupByIterator.ManualGroupByIterator, GroupEndingIterator, GroupMatchingIterator, GroupStartingIterator, ItemCheckingIterator, ItemMappingIterator, JRegexIterator, ListIterator, ListIterator.Of, ListIterator.OfAtomic, ManualGroupIterator, ManualIterator, ManualRegexIterator, MemoSequence.ProgressiveIterator, MergeGroupingIterator, MergeGroupingIterator.ManualMergeGroupingIterator, MultiIndex.SelectedItemsIterator, MultithreadedFocusTrackingIterator, MultithreadedItemMappingIterator, NodeListIterator, OneToOneMappingIterator, net.sf.saxon.expr.RangeIterator, Remove.RemoveIterator, Reverse.ReverseListIterator, SingleAtomicIterator, SingleNodeIterator, SingletonIterator, SortedGroupIterator, SortedIterator, SubsequenceIterator, TailIterator, TwoItemIterator, UntypedAtomizingIterator, ZenoSequence.ZenoSequenceIterator

public interface LastPositionFinder

A LastPositionFinder is an interface implemented by any SequenceIterator that is able to return the position of the last item in the sequence.

Method Summary

Modifier and Type	Method and Description
int	getLength() Get the last position (that is, the number of items in the sequence).
boolean	supportsGetLength() Ask whether this iterator supports use of the getLength() method.

Method Detail

supportsGetLength

boolean supportsGetLength()

Ask whether this iterator supports use of the getLength() method. This method should always be called before calling getLength(), because an iterator that implements this interface may support use of getLength() in some situations and not in others

Returns:

true if the getLength() method can be called to determine the length of the underlying sequence.

getLength

int getLength()

Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The result is undefined if the next() method of the iterator has already returned null. This method must not be called unless the supportsGetLength() has been called and has returned true.

Returns:

the number of items in the sequence

Throws:

UncheckedXPathException - if an error occurs evaluating the sequence in order to determine the number of items

java.lang.ClassCastException - if the capability is not available. (This exception is not guaranteed.)