public class DifferenceEnumeration extends java.lang.Object implements SequenceIterator
Constructor and Description |
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DifferenceEnumeration(SequenceIterator p1,
SequenceIterator p2,
java.util.Comparator<? super NodeInfo> comparer)
Form an enumeration of the difference of two nodesets, that is, the nodes
that are in p1 and that are not in p2.
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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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NodeInfo |
next()
Get the next item in the sequence.
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public DifferenceEnumeration(SequenceIterator p1, SequenceIterator p2, java.util.Comparator<? super NodeInfo> comparer) throws XPathException
p1
- the first operand, with nodes delivered in document orderp2
- the second operand, with nodes delivered in document ordercomparer
- the comparerXPathException
- if a failure occurs reading from either input sequencepublic NodeInfo 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
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