Package net.sf.saxon.tree.iter
Class SingleNodeIterator
java.lang.Object
net.sf.saxon.tree.iter.SingleNodeIterator
- All Implemented Interfaces:
LastPositionFinder
,SequenceIterator
,AxisIterator
,GroundedIterator
,LookaheadIterator
,ReversibleIterator
,UnfailingIterator
public class SingleNodeIterator
extends Object
implements AxisIterator, UnfailingIterator, ReversibleIterator, LastPositionFinder, GroundedIterator, LookaheadIterator
SingletonIterator: an iterator over a sequence of zero or one values
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Field Summary
Fields inherited from interface net.sf.saxon.om.SequenceIterator
GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
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Method Summary
Modifier and TypeMethodDescriptionatomize()
Return the atomized value of the current node.void
close()
Close the iterator.current()
Get the current item in the sequence.Get another iterator over the same sequence of items, positioned at the start of the sequence.int
Get the last position (that is, the number of items in the sequence).int
Get properties of this iterator, as a bit-significant integer.Get a new SequenceIterator that returns the same items in reverse order.Return the string value of the current node.getValue()
boolean
hasNext()
Determine whether there are more items to come.iterateAxis
(byte axis, NodeTest test) Return an iterator over an axis, starting at the current node.static AxisIterator
makeIterator
(NodeInfo item) Factory method.Return a Value containing all the items in the sequence returned by this SequenceIteratorboolean
moveNext()
Move to the next node, without returning it.next()
Get the next item in the sequence.int
position()
Return the current position in the sequence.
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Method Details
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makeIterator
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.
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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 interfaceLookaheadIterator
- Returns:
- true if there are more items
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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 interfaceAxisIterator
- Returns:
- true if there is a next node, false if the end of the sequence has been reached
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next
Description copied from interface:UnfailingIterator
Get the next item in the sequence.- Specified by:
next
in interfaceAxisIterator
- Specified by:
next
in interfaceSequenceIterator
- Specified by:
next
in interfaceUnfailingIterator
- Returns:
- the next Item. If there are no more nodes, return null.
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current
Description copied from interface:UnfailingIterator
Get the current item in the sequence.- Specified by:
current
in interfaceAxisIterator
- Specified by:
current
in interfaceSequenceIterator
- Specified by:
current
in interfaceUnfailingIterator
- Returns:
- the current item, that is, the item most recently returned by next()
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position
public int position()Return the current position in the sequence.- Specified by:
position
in interfaceSequenceIterator
- Specified by:
position
in interfaceUnfailingIterator
- Returns:
- 0 before the first call on next(); 1 before the second call on next(); -1 after the second call on next().
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getLength
public int getLength()Description copied from interface:LastPositionFinder
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 result of getProperties() on the iterator includes the bit settingSequenceIterator.LAST_POSITION_FINDER
- Specified by:
getLength
in interfaceLastPositionFinder
- Returns:
- the number of items in the sequence
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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 interfaceSequenceIterator
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iterateAxis
Return an iterator over an axis, starting at the current node.- Specified by:
iterateAxis
in interfaceAxisIterator
- Parameters:
axis
- the axis to iterate over, using a constant such asAxis.CHILD
test
- a predicate to apply to the nodes before returning them.- Returns:
- an iterator over an axis, starting at the current node
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atomize
Return the atomized value of the current node.- Specified by:
atomize
in interfaceAxisIterator
- Returns:
- the atomized value.
- Throws:
NullPointerException
- if there is no current nodeXPathException
- if the current node cannot be atomized, for example because it is an element node with element-only content.
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getStringValue
Return the string value of the current node.- Specified by:
getStringValue
in interfaceAxisIterator
- Returns:
- the string value, as an instance of CharSequence.
- Throws:
NullPointerException
- if there is no current node
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getAnother
Description copied from interface:UnfailingIterator
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 interfaceAxisIterator
- Specified by:
getAnother
in interfaceSequenceIterator
- Specified by:
getAnother
in interfaceUnfailingIterator
- Returns:
- a new iterator over the same sequence
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getReverseIterator
Description copied from interface:ReversibleIterator
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 interfaceReversibleIterator
- Returns:
- an iterator over the items in reverse order
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getValue
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materialize
Return a Value containing all the items in the sequence returned by this SequenceIterator- Specified by:
materialize
in interfaceGroundedIterator
- Returns:
- the corresponding Value. If the value is a closure or a function call package, it will be evaluated and expanded.
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getProperties
public int getProperties()Get properties of this iterator, as a bit-significant integer.- Specified by:
getProperties
in interfaceSequenceIterator
- Returns:
- the properties of this iterator. This will be some combination of
properties such as
SequenceIterator.GROUNDED
,SequenceIterator.LAST_POSITION_FINDER
, andSequenceIterator.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.
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