## net.sf.saxon.sort
Class DocumentOrderIterator

    java.lang.Object
      |
      +--net.sf.saxon.sort.DocumentOrderIterator

All Implemented Interfaces:
  SequenceIterator, Sortable

public final class DocumentOrderIterator
extends java.lang.Object
implements SequenceIterator, Sortable

DocumentOrderIterator takes as input an iteration of nodes in any order, and returns as output an iteration of the same nodes in document order, eliminating any duplicates.

Constructor Summary
`DocumentOrderIterator(SequenceIterator base, NodeOrderComparer comparer)` Iterate over a sequence in document order.

Method Summary
`int` `compare(int a, int b)` Compare two nodes in document sequence (needed to implement the Sortable interface)
`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.
`Item` `next()` Get the next item in the sequence.
`int` `position()` Get the current position.
`void` `swap(int a, int b)` Swap two nodes (needed to implement the Sortable interface)

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### DocumentOrderIterator

    public DocumentOrderIterator(SequenceIterator base,
                                 NodeOrderComparer comparer)
                          throws XPathException

  Iterate over a sequence in document order.

Method Detail

### compare

    public int compare(int a,
                       int b)

  Compare two nodes in document sequence (needed to implement the Sortable interface)

  Specified by:
    `compare` in interface `Sortable`
  Returns:
    <0 if obj[a]<obj[b], 0 if obj[a]=obj[b], >0 if obj[a]>obj[b]

### swap

    public void swap(int a,
                     int b)

  Swap two nodes (needed to implement the Sortable interface)

  Specified by:
    `swap` in interface `Sortable`

### next

    public Item next()
              throws XPathException

  Description copied from interface: `SequenceIterator`
  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

### current

    public Item current()

  Description copied from interface: `SequenceIterator`
  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().

  Specified by:
    `current` in interface `SequenceIterator`
  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.

### position

    public int position()

  Description copied from interface: `SequenceIterator`
  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.

  Specified by:
    `position` in interface `SequenceIterator`
  Returns:
    the current position, the position of the item returned by the most recent call of next()

### getAnother

    public SequenceIterator getAnother()
                                throws XPathException

  Description copied from interface: `SequenceIterator`
  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