Class SortedIterator

java.lang.Object
net.sf.saxon.sort.SortedIterator
All Implemented Interfaces:
LastPositionFinder, SequenceIterator, Sortable
Direct Known Subclasses:
SortedGroupIterator, SortedTupleIterator

public class SortedIterator extends Object implements SequenceIterator, LastPositionFinder, Sortable
Class to do a sorted iteration
  • Field Details

    • base

      protected SequenceIterator base
    • sortkeys

      protected SortKeyDefinition[] sortkeys
    • comparators

      protected Comparator[] comparators
    • recordSize

      protected int recordSize
    • nodeKeys

      protected Object[] nodeKeys
    • count

      protected int count
    • index

      protected int index
    • context

      protected XPathContext context
  • Constructor Details

  • Method Details

    • setHostLanguage

      public void setHostLanguage(int language)
    • next

      public Item next() throws XPathException
      Get the next item, in sorted order
      Specified by:
      next in interface SequenceIterator
      Returns:
      the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.
      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(). This method does not change the state of the iterator.
      Specified by:
      current in interface SequenceIterator
      Returns:
      the current item, the one most recently returned by a call on next(). Returns 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 usually be zero before the first call on next(), otherwise it will be the number of times that next() has been called. Once next() has returned null, the preferred action is for subsequent calls on position() to return -1, but not all existing implementations follow this practice. (In particular, the EmptyIterator is stateless, and always returns 0 as the value of position(), whether or not next() has been called.)

      This method does not change the state of the iterator.

      Specified by:
      position in interface SequenceIterator
      Returns:
      the current position, the position of the item returned by the most recent call of next(). This is 1 after next() has been successfully called once, 2 after it has been called twice, and so on. If next() has never been called, the method returns zero. If the end of the sequence has been reached, the value returned will always be invalid input: '<'= 0; the preferred value is -1.
    • getLastPosition

      public int getLastPosition() throws XPathException
      Description copied from interface: LastPositionFinder
      Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The result is undefined if the next() method of the iterator has already returned null. This method must not be called unless the result of getProperties() on the iterator includes the bit setting SequenceIterator.LAST_POSITION_FINDER
      Specified by:
      getLastPosition in interface LastPositionFinder
      Throws:
      XPathException
    • 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.

      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.

      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.
    • buildArray

      protected void buildArray() throws XPathException
      Create an array holding the items to be sorted and the values of their sort keys
      Throws:
      XPathException
    • compare

      public int compare(int a, int b)
      Compare two items in sorted sequence (needed to implement the Sortable interface)
      Specified by:
      compare in interface Sortable
      Returns:
      invalid input: '<'0 if obj[a]invalid input: '<'obj[b], 0 if obj[a]=obj[b], >0 if obj[a]>obj[b]
    • swap

      public void swap(int a, int b)
      Swap two items (needed to implement the Sortable interface)
      Specified by:
      swap in interface Sortable