net.sf.saxon.functions

Class DistinctValues.DistinctIterator

public static class DistinctValues.DistinctIterator extends Object implements SequenceIterator

Iterator class to return the distinct values in a sequence
Constructor Summary
DistinctIterator(SequenceIterator base, AtomicSortComparer comparer)
Create an iterator over the distinct values in a sequence
Method Summary
Itemcurrent()
Get the current value in the sequence (the one returned by the most recent call on next()).
SequenceIteratorgetAnother()
Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
intgetProperties()
Get properties of this iterator, as a bit-significant integer.
Itemnext()
Get the next item in the sequence.
intposition()
Get the current position.

Constructor Detail

DistinctIterator

public DistinctIterator(SequenceIterator base, AtomicSortComparer comparer)
Create an iterator over the distinct values in a sequence

Parameters: base the input sequence. This must return atomic values only. comparer The comparer used to obtain comparison keys from each value; these comparison keys are themselves compared using equals().

Method Detail

current

public Item current()
Get the current value in the sequence (the one returned by the most recent call on next()). This will be null before the first call of next().

Returns: the current item, the one most recently returned by a call on next(); or null, if next() has not been called, or if the end of the sequence has been reached.

getAnother

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

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

Throws: net.sf.saxon.trans.XPathException if any error occurs

getProperties

public int getProperties()
Get properties of this iterator, as a bit-significant integer.

Returns: the properties of this iterator. This will be some combination of properties such as GROUNDED, LAST_POSITION_FINDER, and 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.

next

public Item next()
Get the next item in the sequence.

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

Throws: net.sf.saxon.trans.XPathException if an error occurs retrieving the next item

position

public int position()
Get the current position. This will be zero before the first call on next(), otherwise it will be the number of times that next() has been called.

Returns: the current position, the position of the item returned by the most recent call of next()