public class UnionEnumeration extends java.lang.Object implements SequenceIterator<NodeInfo>, LookaheadIterator<NodeInfo>
|Constructor and Description|
Create the iterator.
|Modifier and Type||Method and Description|
Close the iterator.
Get properties of this iterator, as a bit-significant integer.
Determine whether there are more items to come.
Get the next item in the sequence.
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public UnionEnumeration(SequenceIterator<? extends NodeInfo> p1, SequenceIterator<? extends NodeInfo> p2, ItemOrderComparer comparer) throws XPathException
p1- iterator over the first operand sequence (in document order)
p2- iterator over the second operand sequence
comparer- used to test whether nodes are in document order. Different versions are used for intra-document and cross-document operations
XPathException- if an error occurs reading the first item of either operand
public boolean hasNext()
This method must not be called unless the result of getProperties() on the iterator
includes the bit setting
public NodeInfo next() throws XPathException
XPathException- if an error occurs retrieving the next item
public 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.
public int getProperties()
SequenceIterator.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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