net.sf.saxon.om

Class ReverseArrayIterator

Implemented Interfaces:
LastPositionFinder, LookaheadIterator, ReversibleIterator, SequenceIterator, UnfailingIterator
Known Direct Subclasses:
ReverseNodeArrayIterator

public class ReverseArrayIterator
extends java.lang.Object
implements UnfailingIterator, ReversibleIterator, LookaheadIterator, LastPositionFinder

ReverseArrayIterator is used to enumerate items held in an array in reverse order.
Author:
Michael H. Kay

Fields inherited from interface net.sf.saxon.om.SequenceIterator

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

ReverseArrayIterator(Item[] items, int start, int end)
Create an iterator a slice of an array

Method Summary

Item
current()
Get the current item in the sequence.
SequenceIterator
getAnother()
Get another iterator over the same sequence of items, positioned at the start of the sequence.
int
getLastPosition()
Get the last position (that is, the number of items in the sequence).
int
getProperties()
Get properties of this iterator, as a bit-significant integer.
SequenceIterator
getReverseIterator()
Get an iterator that processes the same items in reverse order.
boolean
hasNext()
Determine whether there are more items to come.
Item
next()
Get the next item in the sequence.
int
position()
Get the current position

Constructor Details

ReverseArrayIterator

public ReverseArrayIterator(Item[] items,
                            int start,
                            int end)
Create an iterator a slice of an array
Parameters:
items - The array of items
start - The first item in the array to be be used (this will be the last one in the resulting iteration). Zero-based.
end - The item after the last one in the array to be used (this will be the first one to be returned by the iterator). Zero-based.

Method Details

current

public Item current()
Get the current item in the sequence.
Specified by:
current in interface UnfailingIterator
current in interface SequenceIterator
Returns:
the current item, that is, the item most recently returned by next()

getAnother

public SequenceIterator getAnother()
Get another iterator over the same sequence of items, positioned at the start of the sequence. It must be possible to call this method at any time, whether none, some, or all of the items in the original iterator have been read. The method is non-destructive: it does not change the state of the original iterator.
Specified by:
getAnother in interface UnfailingIterator
getAnother in interface SequenceIterator
Returns:
a new iterator over the same sequence

getLastPosition

public int getLastPosition()
Specified by:
getLastPosition in interface LastPositionFinder

getProperties

public int getProperties()
Get properties of this iterator, as a bit-significant integer.
Specified by:
getProperties in interface SequenceIterator
Returns:
the properties of this iterator. This will be some combination of properties such as SequenceIterator.GROUNDED, SequenceIterator.LAST_POSITION_FINDER, and SequenceIterator.LOOKAHEAD. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.

getReverseIterator

public SequenceIterator getReverseIterator()
Get an iterator that processes the same items in reverse order. Since this iterator is processing the items backwards, this method returns an ArrayIterator that processes them forwards.
Specified by:
getReverseIterator in interface ReversibleIterator
Returns:
a new ArrayIterator

hasNext

public boolean hasNext()
Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.
Specified by:
hasNext in interface LookaheadIterator
Returns:
true if there are more items in the sequence

next

public Item next()
Get the next item in the sequence.
Specified by:
next in interface UnfailingIterator
next in interface SequenceIterator
Returns:
the next Item. If there are no more nodes, return null.

position

public int position()
Get the current position
Specified by:
position in interface UnfailingIterator
position in interface SequenceIterator
Returns:
the position of the current item (the item most recently returned by next()), starting at 1 for the first node