net.sf.saxon.tree.iter
Class ArrayIterator<T extends Item>

java.lang.Object
  net.sf.saxon.tree.iter.ArrayIterator<T>

All Implemented Interfaces:

LastPositionFinder<T>, SequenceIterator<T>, GroundedIterator<T>, LookaheadIterator<T>, ReversibleIterator<T>, UnfailingIterator<T>

public class ArrayIterator<T extends Item>
extends Object
implements UnfailingIterator<T>, ReversibleIterator<T>, LastPositionFinder<T>, LookaheadIterator<T>, GroundedIterator<T>

ArrayIterator is used to enumerate items held in an array. The items are always held in the correct sorted order for the sequence.

Author:

Michael H. Kay

Field Summary

protected int	end
protected T[]	items
protected int	start

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

ArrayIterator(T[] nodes)
Create an iterator over all the items in an array

ArrayIterator(T[] items, int start, int end)
Create an iterator over a range of an array.

Method Summary

void	close() Close the iterator.
T	current() Get the current item in the array
ArrayIterator<T>	getAnother() Get another iterator over the same items
T[]	getArray() Get the underlying array
int	getEndPosition() Get the end position in the array
int	getLength() Get the number of items in the part of the array being processed
int	getProperties() Get properties of this iterator, as a bit-significant integer.
SequenceIterator<T>	getReverseIterator() Get an iterator that processes the same items in reverse order
int	getStartPosition() Get the initial start position
boolean	hasNext() Test whether there are any more items
SequenceIterator<T>	makeSliceIterator(int min, int max) Create a new ArrayIterator over the same items, with a different start point and end point
GroundedValue	materialize() Return a SequenceValue containing all the items in the sequence returned by this SequenceIterator
T	next() Get the next item in the array
int	position() Get the position of the current item in the array

Methods inherited from class java.lang.Object

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

Field Detail

items

protected T extends Item[] items

start

protected int start

end

protected int end

Constructor Detail

ArrayIterator

public ArrayIterator(T[] nodes)

Create an iterator over all the items in an array

Parameters:

nodes - the array (of any items, not necessarily nodes) to be processed by the iterator

ArrayIterator

public ArrayIterator(T[] items,
                     int start,
                     int end)

Create an iterator over a range of an array. Note that the start position is zero-based

Parameters:

items - the array (of nodes or simple values) to be processed by the iterator

start - the position of the first item to be processed (numbering from zero). Must be between zero and nodes.length-1; if not, undefined exceptions are likely to occur.

end - position of first item that is NOT returned, zero-based. Must be beween 1 and nodes.length; if not, undefined exceptions are likely to occur.

Method Detail

makeSliceIterator

public SequenceIterator<T> makeSliceIterator(int min,
                                             int max)

Create a new ArrayIterator over the same items, with a different start point and end point

Parameters:

min - the start position (1-based) of the new ArrayIterator relative to the original

max - the end position (1-based) of the last item to be delivered by the new ArrayIterator, relative to the original. For example, min=2, max=3 delivers the two items ($base[2], $base[3]). Set this to Integer.MAX_VALUE if there is no end limit.

Returns:

an iterator over the items between the min and max positions

hasNext

public boolean hasNext()

Test whether there are any more items

Specified by:

hasNext in interface LookaheadIterator<T extends Item>

Returns:

true if there are more items

next

public T next()

Get the next item in the array

Specified by:

next in interface SequenceIterator<T extends Item>

Specified by:

next in interface UnfailingIterator<T extends Item>

Returns:

the next item in the array

current

public T current()

Get the current item in the array

Specified by:

current in interface SequenceIterator<T extends Item>

Specified by:

current in interface UnfailingIterator<T extends Item>

Returns:

the item returned by the most recent call of next()

position

public int position()

Get the position of the current item in the array

Specified by:

position in interface SequenceIterator<T extends Item>

Specified by:

position in interface UnfailingIterator<T extends Item>

Returns:

the current position (starting at 1 for the first item)

getLength

public int getLength()

Get the number of items in the part of the array being processed

Specified by:

getLength in interface LastPositionFinder<T extends Item>

Returns:

the number of items; equivalently, the position of the last item

close

public void close()

Description copied from interface: SequenceIterator

Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

(Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

Specified by:

close in interface SequenceIterator<T extends Item>

getAnother

public ArrayIterator<T> getAnother()

Get another iterator over the same items

Specified by:

getAnother in interface SequenceIterator<T extends Item>

Specified by:

getAnother in interface UnfailingIterator<T extends Item>

Returns:

a new ArrayIterator

getReverseIterator

public SequenceIterator<T> getReverseIterator()

Get an iterator that processes the same items in reverse order

Specified by:

getReverseIterator in interface ReversibleIterator<T extends Item>

Returns:

a new ArrayIterator

getArray

public T[] getArray()

Get the underlying array

Returns:

the underlying array being processed by the iterator

getStartPosition

public int getStartPosition()

Get the initial start position

Returns:

the start position of the iterator in the array (zero-based)

getEndPosition

public int getEndPosition()

Get the end position in the array

Returns:

the position in the array (zero-based) of the first item not included in the iteration

materialize

public GroundedValue materialize()

Return a SequenceValue containing all the items in the sequence returned by this SequenceIterator

Specified by:

materialize in interface GroundedIterator<T extends Item>

Returns:

the corresponding SequenceValue

getProperties

public int getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator<T extends Item>

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.