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:
Closeable,AutoCloseable,LastPositionFinder,SequenceIterator<NodeInfo>,AxisIterator,GroundedIterator<NodeInfo>,LookaheadIterator<NodeInfo>,ReversibleIterator<NodeInfo>,UnfailingIterator<NodeInfo>
public class SingleNodeIterator extends Object implements AxisIterator, ReversibleIterator<NodeInfo>, LastPositionFinder, GroundedIterator<NodeInfo>, LookaheadIterator<NodeInfo>
SingleNodeIterator: an iterator over a sequence of zero or one nodes
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Field Summary
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Fields inherited from interface net.sf.saxon.om.SequenceIterator
ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclose()Close the iterator.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.GroundedValue<NodeInfo>getResidue()Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position.SequenceIterator<NodeInfo>getReverseIterator()Get a new SequenceIterator that returns the same items in reverse order.NodeInfogetValue()booleanhasNext()Determine whether there are more items to come.static AxisIteratormakeIterator(NodeInfo item)Factory method.GroundedValue<NodeInfo>materialize()Return a Value containing all the items in the sequence returned by this SequenceIteratorNodeInfonext()Get the next item in the sequence.-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface net.sf.saxon.om.SequenceIterator
forEachOrFail
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Methods inherited from interface net.sf.saxon.tree.iter.UnfailingIterator
firstWith, forEach, toGroundedValue, toList
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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<NodeInfo>- Returns:
- true if there are more items
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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<NodeInfo>- Specified by:
nextin interfaceUnfailingIterator<NodeInfo>- Returns:
- the next Item. If there are no more items, return null.
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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.For example, the iterator returned by the unparsed-text-lines() function has a close() method that causes the underlying input stream to be closed, whether or not the file has been read to completion.
Closing an iterator is important 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 interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Specified by:
closein interfaceSequenceIterator<NodeInfo>
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getReverseIterator
public SequenceIterator<NodeInfo> 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<NodeInfo>- Returns:
- an iterator over the items in reverse order
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getValue
public NodeInfo getValue()
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materialize
public GroundedValue<NodeInfo> materialize()
Return a Value containing all the items in the sequence returned by this SequenceIterator- Specified by:
materializein interfaceGroundedIterator<NodeInfo>- Specified by:
materializein interfaceSequenceIterator<NodeInfo>- 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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getResidue
public GroundedValue<NodeInfo> getResidue() throws XPathException
Description copied from interface:GroundedIteratorReturn a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position. This should be an "in-memory" value, not a Closure. This method does not change the state of the iterator (in particular, it does not consume the iterator).- Specified by:
getResiduein interfaceGroundedIterator<NodeInfo>- Returns:
- the corresponding Value
- Throws:
XPathException- in the cases of subclasses (such as the iterator over a MemoClosure) which cause evaluation of expressions while materializing the value.
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getProperties
public int getProperties()
Get properties of this iterator, as a bit-significant integer.- Specified by:
getPropertiesin interfaceSequenceIterator<NodeInfo>- 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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