Package net.sf.saxon.tree.iter
Class SingleNodeIterator
- java.lang.Object
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- net.sf.saxon.tree.iter.SingleNodeIterator
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- All Implemented Interfaces:
LastPositionFinder,SequenceIterator,AxisIterator,GroundedIterator,LookaheadIterator,ReversibleIterator,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
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Field Summary
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Fields inherited from interface net.sf.saxon.om.SequenceIterator
GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description Valueatomize()Return the atomized value of the current node.voidclose()Close the iterator.NodeInfocurrent()Get the current item in the sequence.AxisIteratorgetAnother()Get another iterator over the same sequence of items, positioned at the start of the sequence.intgetLength()Get the last position (that is, the number of items in the sequence).intgetProperties()Get properties of this iterator, as a bit-significant integer.SequenceIteratorgetReverseIterator()Get a new SequenceIterator that returns the same items in reverse order.java.lang.CharSequencegetStringValue()Return the string value of the current node.ItemgetValue()booleanhasNext()Determine whether there are more items to come.AxisIteratoriterateAxis(byte axis, NodeTest test)Return an iterator over an axis, starting at the current node.static AxisIteratormakeIterator(NodeInfo item)Factory method.GroundedValuematerialize()Return a Value containing all the items in the sequence returned by this SequenceIteratorbooleanmoveNext()Move to the next node, without returning it.NodeInfonext()Get the next item in the sequence.intposition()Return the current position in the sequence.
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Method Detail
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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.
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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:
hasNextin 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:
moveNextin interfaceAxisIterator- Returns:
- true if there is a next node, false if the end of the sequence has been reached
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next
public NodeInfo next()
Description copied from interface:UnfailingIteratorGet the next item in the sequence.- Specified by:
nextin interfaceAxisIterator- Specified by:
nextin interfaceSequenceIterator- Specified by:
nextin interfaceUnfailingIterator- Returns:
- the next Item. If there are no more nodes, return null.
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current
public NodeInfo current()
Description copied from interface:UnfailingIteratorGet the current item in the sequence.- Specified by:
currentin interfaceAxisIterator- Specified by:
currentin interfaceSequenceIterator- Specified by:
currentin 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:
positionin interfaceSequenceIterator- Specified by:
positionin 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:LastPositionFinderGet 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:
getLengthin interfaceLastPositionFinder- Returns:
- the number of items in the sequence
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close
public void close()
Description copied from interface:SequenceIteratorClose 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:
closein interfaceSequenceIterator
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iterateAxis
public AxisIterator iterateAxis(byte axis, NodeTest test)
Return an iterator over an axis, starting at the current node.- Specified by:
iterateAxisin interfaceAxisIterator- Parameters:
axis- the axis to iterate over, using a constant such asAxis.CHILDtest- 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
public Value atomize() throws XPathException
Return the atomized value of the current node.- Specified by:
atomizein interfaceAxisIterator- Returns:
- the atomized value.
- Throws:
java.lang.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
public java.lang.CharSequence getStringValue()
Return the string value of the current node.- Specified by:
getStringValuein interfaceAxisIterator- Returns:
- the string value, as an instance of CharSequence.
- Throws:
java.lang.NullPointerException- if there is no current node
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getAnother
public AxisIterator getAnother()
Description copied from interface:UnfailingIteratorGet 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:
getAnotherin interfaceAxisIterator- Specified by:
getAnotherin interfaceSequenceIterator- Specified by:
getAnotherin interfaceUnfailingIterator- Returns:
- a new iterator over the same sequence
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getReverseIterator
public SequenceIterator getReverseIterator()
Description copied from interface:ReversibleIteratorGet 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:
getReverseIteratorin interfaceReversibleIterator- Returns:
- an iterator over the items in reverse order
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getValue
public Item getValue()
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materialize
public GroundedValue materialize()
Return a Value containing all the items in the sequence returned by this SequenceIterator- Specified by:
materializein 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:
getPropertiesin 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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