public static class DistinctValues.DistinctIterator extends java.lang.Object implements SequenceIterator
| Constructor and Description |
|---|
DistinctIterator(SequenceIterator base,
StringCollator collator,
XPathContext context)
Create an iterator over the distinct values in a sequence
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| Modifier and Type | Method and Description |
|---|---|
void |
close()
Close the iterator.
|
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.
|
AtomicValue |
next()
Get the next item in the sequence.
|
public DistinctIterator(SequenceIterator base, StringCollator collator, XPathContext context)
base - the input sequence. This must return atomic values only.collator - The comparer used to obtain comparison keys from each value;
these comparison keys are themselves compared using equals().context - the XPath dynamic contextpublic AtomicValue next()
next in interface SequenceIteratorpublic void close()
SequenceIteratorFor 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.Closeableclose in interface java.lang.AutoCloseableclose in interface SequenceIteratorpublic void discharge()
SequenceIteratorSequenceIterator.close() will be called when no more items are needed.discharge in interface SequenceIteratorCopyright (c) 2004-2022 Saxonica Limited. All rights reserved.