net.sf.saxon.tree.iter
Class AxisIteratorImpl

java.lang.Object
  net.sf.saxon.tree.iter.AxisIteratorImpl

All Implemented Interfaces:

SequenceIterator, AxisIterator, UnfailingIterator

Direct Known Subclasses:

Navigator.AxisFilter, Navigator.BaseEnumeration, Navigator.EmptyTextFilter

public abstract class AxisIteratorImpl
extends Object
implements AxisIterator

A SequenceIterator is used to iterate over a sequence. An AxisIterator is a SequenceIterator that always iterates over a set of nodes, and that throws no exceptions; it also supports the ability to find the last() position, again with no exceptions. This class is an abstract implementation of AxisIterator that is used as a base class for many concrete implementations. The main functionality that it provides is maintaining the current position.

Field Summary

protected NodeInfo	current
protected int	position

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

AxisIteratorImpl()

Method Summary

Value	atomize() Return the atomized value of the current node.
void	close() Close the iterator.
Item	current() Get the current node in the sequence.
int	getProperties() Get properties of this iterator, as a bit-significant integer.
CharSequence	getStringValue() Return the string value of the current node.
AxisIterator	iterateAxis(byte axis, NodeTest test) Return an iterator over an axis, starting at the current node.
boolean	moveNext() Move to the next node, without returning it.
int	position() Get the current position

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.tree.iter.UnfailingIterator

getAnother, next

Field Detail

position

protected int position

current

protected NodeInfo current

Constructor Detail

AxisIteratorImpl

public AxisIteratorImpl()

Method Detail

moveNext

public boolean moveNext()

Move to the next node, without returning it. Returns true if there is a next node, false if the end of the sequence has been reached. After calling this method, the current node may be retrieved using the current() function.

Specified by:

moveNext in interface AxisIterator

current

public Item current()

Get the current node in the sequence.

Specified by:

current in interface SequenceIterator

Specified by:

current in interface UnfailingIterator

Returns:

the node returned by the most recent call on next()

position

public final int position()

Get the current position

Specified by:

position in interface SequenceIterator

Specified by:

position in interface UnfailingIterator

Returns:

the position of the most recent node returned by next()

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

iterateAxis

public AxisIterator iterateAxis(byte axis,
                                NodeTest test)

Return an iterator over an axis, starting at the current node.

Specified by:

iterateAxis in interface AxisIterator

Parameters:

axis - the axis to iterate over, using a constant such as Axis.CHILD

test - a predicate to apply to the nodes before returning them.

atomize

public Value atomize()
              throws XPathException

Return the atomized value of the current node.

Specified by:

atomize in interface AxisIterator

Returns:

the atomized value.

Throws:

NullPointerException - if there is no current node

XPathException

getStringValue

public CharSequence getStringValue()

Return the string value of the current node.

Specified by:

getStringValue in interface AxisIterator

Returns:

the string value, as an instance of CharSequence.

Throws:

NullPointerException - if there is no current node

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.