public final class ContextMappingIterator extends java.lang.Object implements SequenceIterator
This is related to the
MappingIterator class: it differs in that it
sets each item being processed as the context item
|Constructor and Description|
Construct a ContextMappingIterator that will apply a specified ContextMappingFunction to each Item returned by the base iterator.
|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.
public ContextMappingIterator(ContextMappingFunction action, XPathContext context)
action- the mapping function to be applied
context- the processing context. The mapping function is applied to each item returned by context.getCurrentIterator() in turn.
public Item next()
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.
Closing an iterator is not necessary if the iterator is read to completion: if a call
SequenceIterator.next() returns null, the iterator will be closed automatically. An explicit
SequenceIterator.close() is needed only when iteration is abandoned prematurely.
public void discharge()
SequenceIterator.close()will be called when no more items are needed.
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