- All Implemented Interfaces:
public final class CardinalityCheckingIterator extends java.lang.Object implements SequenceIteratorCardinalityCheckingIterator returns the items in an underlying sequence unchanged, but checks that the number of items conforms to the required cardinality. Because cardinality checks are required to take place even if the consumer of the sequence does not require all the items, we read the first two items at initialization time. This is sufficient to perform the checks; after that we can simply return the items from the base sequence.
All Methods Instance Methods Concrete Methods Modifier and Type Method Description
close()Close the iterator.
next()Get the next item in the sequence.
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public CardinalityCheckingIterator(SequenceIterator base, int requiredCardinality, RoleDiagnostic role, Location locator) throws XPathExceptionConstruct an CardinalityCheckingIterator that will return the same items as the base sequence, checking how many there are
base- the base iterator
requiredCardinality- the required Cardinality
role- information for use if a failure occurs
locator- the location in the source stylesheet or query
XPathException- if a failure is detected
public Item next() throws XPathExceptionDescription copied from interface:
SequenceIteratorGet the next item in the sequence. This method changes the state of the iterator.
- Specified by:
- the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.
XPathException- if an error occurs retrieving the next item
public void close()Description copied from interface:
SequenceIteratorClose the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.
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.