net.sf.saxon.functions

Class DistinctValues.DistinctIterator

java.lang.Object

net.sf.saxon.functions.DistinctValues.DistinctIterator

All Implemented Interfaces:

SequenceIterator

Enclosing class:

DistinctValues

public static class DistinctValues.DistinctIterator
extends Object
implements SequenceIterator

Iterator class to return the distinct values in a sequence

Field Summary

Fields inherited from interface net.sf.saxon.om.SequenceIterator

ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Constructors

Constructor and Description
DistinctValues.DistinctIterator(SequenceIterator base, StringCollator collator, XPathContext context) Create an iterator over the distinct values in a sequence

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the iterator.
DistinctValues.DistinctIterator	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.
AtomicValue	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

Constructor Detail

DistinctValues.DistinctIterator

public DistinctValues.DistinctIterator(SequenceIterator base,
                               StringCollator collator,
                               XPathContext context)

Create an iterator over the distinct values in a sequence

Parameters:

base - the input sequence. This must return atomic values only.

collator - The comparer used to obtain comparison keys from each value; these comparison keys are themselves compared using equals().

context - the XPath dynamic context

Method Detail

next

public AtomicValue next()
                 throws XPathException

Get the next item in the sequence.

Specified by:

next in interface SequenceIterator

Returns:

the next item, or null if there are no more items.

Throws:

XPathException - if an error occurs retrieving the next item

close

public void close()

Description copied from interface: SequenceIterator

Close 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.

(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.)

Specified by:

close in interface SequenceIterator

getAnother

public DistinctValues.DistinctIterator getAnother()
                                           throws XPathException

Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

Specified by:

getAnother in interface SequenceIterator

Returns:

a SequenceIterator that iterates over the same items, positioned before the first item

Throws:

XPathException - if any error occurs

getProperties

public int getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator

Returns:

the properties of this iterator. This will be some combination of properties such as 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.