net.sf.saxon.om

Class SingleNodeIterator

Implemented Interfaces:
AxisIterator, GroundedIterator, LastPositionFinder, LookaheadIterator, ReversibleIterator, SequenceIterator, UnfailingIterator

public class SingleNodeIterator
extends java.lang.Object
implements AxisIterator, UnfailingIterator, ReversibleIterator, LastPositionFinder, GroundedIterator, LookaheadIterator

SingletonIterator: an iterator over a sequence of zero or one values

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Method Summary

Value
atomize()
Return the atomized value of the current node.
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 a new SequenceIterator that returns the same items in reverse order.
CharSequence
getStringValue()
Return the string value of the current node.
Item
getValue()
boolean
hasNext()
Determine whether there are more items to come.
AxisIterator
iterateAxis(byte axis, NodeTest test)
Return an iterator over an axis, starting at the current node.
static AxisIterator
makeIterator(NodeInfo item)
Factory method.
GroundedValue
materialize()
Return a Value containing all the items in the sequence returned by this SequenceIterator
boolean
moveNext()
Move to the next node, without returning it.
Item
next()
Get the next item in the sequence.
int
position()
Return the current position in the sequence.

Method Details

atomize

public Value atomize()
            throws XPathException
Return the atomized value of the current node.
Specified by:
atomize in interface AxisIterator
Returns:
the atomized value.

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 a new SequenceIterator that returns the same items in reverse order. If this SequenceIterator is an AxisIterator, then the returned SequenceIterator must also be an AxisIterator.
Specified by:
getReverseIterator in interface ReversibleIterator
Returns:
an iterator over the items in reverse order

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.

getValue

public Item getValue()

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

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.

makeIterator

public static AxisIterator makeIterator(NodeInfo item)
Factory method.
Parameters:
item - the item to iterate over
Returns:
a SingletonIterator over the supplied item, or an EmptyIterator if the supplied item is null.

materialize

public GroundedValue materialize()
Return a Value containing all the items in the sequence returned by this SequenceIterator
Specified by:
materialize in interface GroundedIterator
Returns:
the corresponding Value. If the value is a closure or a function call package, it will be evaluated and expanded.

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

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()
Return the current position in the sequence.
Specified by:
position in interface UnfailingIterator
position in interface SequenceIterator
Returns:
0 before the first call on next(); 1 before the second call on next(); -1 after the second call on next().