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java.lang.Object net.sf.saxon.expr.CardinalityCheckingIterator
public final class CardinalityCheckingIterator
CardinalityCheckingIterator 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.
Field Summary |
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Fields inherited from interface net.sf.saxon.om.SequenceIterator |
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GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD |
Constructor Summary | |
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CardinalityCheckingIterator(SequenceIterator base,
int requiredCardinality,
RoleLocator role,
SourceLocator locator)
Construct an CardinalityCheckingIterator that will return the same items as the base sequence, checking how many there are |
Method Summary | |
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void |
close()
Close the iterator. |
Item |
current()
Get the current value in the sequence (the one returned by the most recent call on next()). |
SequenceIterator |
getAnother()
Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence. |
int |
getProperties()
Get properties of this iterator, as a bit-significant integer. |
Item |
next()
Get the next item in the sequence. |
int |
position()
Get the current position. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public CardinalityCheckingIterator(SequenceIterator base, int requiredCardinality, RoleLocator role, SourceLocator locator) throws XPathException
base
- the base iteratorrequiredCardinality
- the required Cardinality
XPathException
Method Detail |
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public Item next() throws XPathException
SequenceIterator
next
in interface SequenceIterator
XPathException
- if an error occurs retrieving the next itempublic Item current()
SequenceIterator
current
in interface SequenceIterator
public int position()
SequenceIterator
This method does not change the state of the iterator.
position
in interface SequenceIterator
public void close()
SequenceIterator
(Currently, closing an iterator is important only 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.)
close
in interface SequenceIterator
public SequenceIterator getAnother() throws XPathException
SequenceIterator
This method allows access to all the items in the sequence without disturbing the current position of the iterator. Internally, its main use is in evaluating the last() function.
This method does not change the state of the iterator.
getAnother
in interface SequenceIterator
XPathException
- if any error occurspublic int getProperties()
getProperties
in interface SequenceIterator
SequenceIterator.GROUNDED
,
SequenceIterator.LAST_POSITION_FINDER
,
and 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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