Package org.apache.lucene.search.comparators

Class TermOrdValComparator

java.lang.Object
org.apache.lucene.search.FieldComparator<BytesRef>
org.apache.lucene.search.comparators.TermOrdValComparator
public class TermOrdValComparator extends FieldComparator<BytesRef>
Sorts by field's natural Term sort order, using ordinals. This is functionally equivalent to FieldComparator.TermValComparator, but it first resolves the string to their relative ordinal positions (using the index returned by LeafReader.getSortedDocValues(String)), and does most comparisons using the ordinals. For medium to large results, this comparator will be much faster than FieldComparator.TermValComparator. For very small result sets it may be slower.

  • Constructor Details

    • TermOrdValComparator

      public TermOrdValComparator(int numHits, String field, boolean sortMissingLast, boolean reverse, Pruning pruning)
      Creates this, with control over how missing values are sorted. Pass sortMissingLast=true to put missing values at the end.

  • Method Details

    • disableSkipping

      public void disableSkipping()
      Description copied from class: FieldComparator
      Informs the comparator that the skipping of documents should be disabled. This function is called by TopFieldCollector in cases when the skipping functionality should not be applied or not necessary. An example could be when search sort is a part of the index sort, and can be already efficiently handled by TopFieldCollector, and doing extra work for skipping in the comparator is redundant.
      Overrides:
      disableSkipping in class FieldComparator<BytesRef>

    • setSingleSort

      public void setSingleSort()
      Description copied from class: FieldComparator
      Informs the comparator that sort is done on this single field. This is useful to enable some optimizations for skipping non-competitive documents.
      Overrides:
      setSingleSort in class FieldComparator<BytesRef>

    • compare

      public int compare(int slot1, int slot2)
      Description copied from class: FieldComparator
      Compare hit at slot1 with hit at slot2.
      Specified by:
      compare in class FieldComparator<BytesRef>
      Parameters:
      slot1 - first slot to compare
      slot2 - second slot to compare
      Returns:
      any N < 0 if slot2's value is sorted after slot1, any N > 0 if the slot2's value is sorted before slot1 and 0 if they are equal

    • getSortedDocValues

      protected SortedDocValues getSortedDocValues(LeafReaderContext context, String field) throws IOException
      Retrieves the SortedDocValues for the field in this segment
      Throws:
      IOException

    • getLeafComparator

      public LeafFieldComparator getLeafComparator(LeafReaderContext context) throws IOException
      Description copied from class: FieldComparator
      Get a per-segment LeafFieldComparator to collect the given LeafReaderContext. All docIDs supplied to this LeafFieldComparator are relative to the current reader (you must add docBase if you need to map it to a top-level docID).
      Specified by:
      getLeafComparator in class FieldComparator<BytesRef>
      Parameters:
      context - current reader context
      Returns:
      the comparator to use for this segment
      Throws:
      IOException - if there is a low-level IO error

    • setTopValue

      public void setTopValue(BytesRef value)
      Description copied from class: FieldComparator
      Record the top value, for future calls to LeafFieldComparator.compareTop(int). This is only called for searches that use searchAfter (deep paging), and is called before any calls to FieldComparator.getLeafComparator(LeafReaderContext).
      Specified by:
      setTopValue in class FieldComparator<BytesRef>

    • value

      public BytesRef value(int slot)
      Description copied from class: FieldComparator
      Return the actual value in the slot.
      Specified by:
      value in class FieldComparator<BytesRef>
      Parameters:
      slot - the value
      Returns:
      value in this slot

    • compareValues

      public int compareValues(BytesRef val1, BytesRef val2)
      Description copied from class: FieldComparator
      Returns a negative integer if first is less than second, 0 if they are equal and a positive integer otherwise. Default impl to assume the type implements Comparable and invoke .compareTo; be sure to override this method if your FieldComparator's type isn't a Comparable or if your values may sometimes be null
      Overrides:
      compareValues in class FieldComparator<BytesRef>