public interface SequenceIterator extends java.io.Closeable
The objects returned by the SequenceIterator will generally be either nodes
(class NodeInfo), singleton values (class AtomicValue), or function items: these are represented
collectively by the interface
The interface to SequenceIterator is changed in Saxon 9.6 to drop support for the
current() and position() methods. Internal iterators no longer need to maintain the values
of the current item or the current position. This information is needed (in general) only
for an iterator that acts as the current focus; that is, an iterator stored as the current
iterator in an XPathContext. SequenceIterators than maintain the value of position()
and last() are represented by the interface
|Modifier and Type||Method and Description|
Close the iterator.
Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence.
Get the next item in the sequence.
UncheckedXPathException- if an error occurs retrieving the next item
default void close()
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
next() returns null, the iterator will be closed automatically. An explicit
close() is needed only when iteration is abandoned prematurely.
default void discharge()
close()will be called when no more items are needed.
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