net.sf.saxon.sort
Class SortedTupleIterator

java.lang.Object
  net.sf.saxon.sort.SortedIterator
      net.sf.saxon.sort.SortedTupleIterator

All Implemented Interfaces:

LastPositionFinder, LookaheadIterator, SequenceIterator, Sortable

public class SortedTupleIterator
extends SortedIterator

A SortedTupleIterator is a modified SortedIterator. Whereas the sorted iterator used by XSLT computes the sort key of each item in a sequence, using that item as the context item, the SortedTupleIterator used by XQuery precomputes the sort keys from scratch; they do not need to be a function of the item being sorted.

The items returned by the SortedTupleIterator are instance of ObjectValue, which encapsulate a Value representing the contents of the tuple.

Field Summary

Fields inherited from class net.sf.saxon.sort.SortedIterator

base, comparators, context, count, nodeKeys, position, recordSize, sortKeyEvaluator

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

SortedTupleIterator(XPathContext context, SequenceIterator base, AtomicComparer[] comparators)
Create a sorted tuple iterator

Method Summary

protected void

buildArray() Override the method that builds the array of values and sort keys.

Methods inherited from class net.sf.saxon.sort.SortedIterator

close, compare, current, getAnother, getLastPosition, getProperties, hasNext, next, position, setHostLanguage, swap

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SortedTupleIterator

public SortedTupleIterator(XPathContext context,
                           SequenceIterator base,
                           AtomicComparer[] comparators)

Create a sorted tuple iterator

Parameters:

context - the dynamic context

base - the base iterator, which returns the unsorted tuples. Each tuple is represented by an ObjectValue which wraps an array of Value objects. The first Value object represents the tuple itself. Subsequent Value objects represent the sort key values, in order.

comparators - the comparators used for comparing sort keys

Method Detail

buildArray

protected void buildArray()
                   throws XPathException

Override the method that builds the array of values and sort keys.

Overrides:

buildArray in class SortedIterator

Throws:

XPathException