public class UntypedAtomizingIterator extends java.lang.Object implements SequenceIterator, LastPositionFinder, LookaheadIterator
This UntypedAtomizingIterator is used only when it is known that the input sequence consists entirely of nodes, and that all nodes will be untyped.
Constructor and Description |
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UntypedAtomizingIterator(SequenceIterator base)
Construct an AtomizingIterator that will atomize the values returned by the base iterator.
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Modifier and Type | Method and Description |
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void |
close()
Close the iterator.
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void |
discharge()
Calling this method instructs the iterator to release any resources it holds, while still
remaining able to deliver the remaining items in the sequence.
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int |
getLength()
Get the last position (that is, the number of items in the sequence).
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boolean |
hasNext()
Determine whether there are more items to come.
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AtomicValue |
next()
Get the next item in the sequence.
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boolean |
supportsGetLength()
Ask whether this iterator supports use of the
getLength() method. |
boolean |
supportsHasNext()
Ask whether the hasNext() method can be called.
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public UntypedAtomizingIterator(SequenceIterator base)
base
- the base iteratorpublic AtomicValue next()
SequenceIterator
next
in interface SequenceIterator
public void close()
SequenceIterator
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.
Closing an iterator is not necessary if the iterator is read to completion: if a call
on SequenceIterator.next()
returns null, the iterator will be closed automatically. An explicit
call on SequenceIterator.close()
is needed only when iteration is abandoned prematurely.
close
in interface java.io.Closeable
close
in interface java.lang.AutoCloseable
close
in interface SequenceIterator
public void discharge()
SequenceIterator
SequenceIterator.close()
will be called when no more items are needed.discharge
in interface SequenceIterator
public boolean supportsGetLength()
getLength()
method. This
method should always be called before calling getLength()
, because an iterator
that implements this interface may support use of getLength()
in some situations
and not in otherssupportsGetLength
in interface LastPositionFinder
getLength()
method can be called to determine the length
of the underlying sequence.public int getLength()
LastPositionFinder
LastPositionFinder.supportsGetLength()
has been called
and has returned true.getLength
in interface LastPositionFinder
public boolean supportsHasNext()
LookaheadIterator
supportsHasNext
in interface LookaheadIterator
LookaheadIterator.hasNext()
method is availablepublic boolean hasNext()
LookaheadIterator
This method must not be called unless the result of LookaheadIterator.supportsHasNext()
is true.
hasNext
in interface LookaheadIterator
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