Package org.apache.lucene.search

Class SortField

java.lang.Object
org.apache.lucene.search.SortField
Direct Known Subclasses:
DoubleValuesSource.DoubleValuesSortField, FeatureSortField, LatLonPointSortField, LongValuesSource.LongValuesSortField, SortedNumericSortField, SortedSetSortField, ToParentBlockJoinSortField, ValueSource.ValueSourceSortField, XYPointSortField
public class SortField extends Object
Stores information about how to sort documents by terms in an individual field. Fields must be indexed in order to sort by them.

Created: Feb 11, 2004 1:25:29 PM

Since:
lucene 1.4
See Also:

  • Field Details

  • Constructor Details

    • SortField

      public SortField(String field, SortField.Type type)
      Creates a sort by terms in the given field with the type of term values explicitly given.
      Parameters:
      field - Name of field to sort by. Can be null if type is SCORE or DOC.
      type - Type of values in the terms.

    • SortField

      public SortField(String field, SortField.Type type, boolean reverse)
      Creates a sort, possibly in reverse, by terms in the given field with the type of term values explicitly given.
      Parameters:
      field - Name of field to sort by. Can be null if type is SCORE or DOC.
      type - Type of values in the terms.
      reverse - True if natural order should be reversed.

    • SortField

      public SortField(String field, FieldComparatorSource comparator)
      Creates a sort with a custom comparison function.
      Parameters:
      field - Name of field to sort by; cannot be null.
      comparator - Returns a comparator for sorting hits.

    • SortField

      public SortField(String field, FieldComparatorSource comparator, boolean reverse)
      Creates a sort, possibly in reverse, with a custom comparison function.
      Parameters:
      field - Name of field to sort by; cannot be null.
      comparator - Returns a comparator for sorting hits.
      reverse - True if natural order should be reversed.

  • Method Details

    • readType

      protected static SortField.Type readType(DataInput in) throws IOException
      Throws:
      IOException

    • serialize

      private void serialize(DataOutput out) throws IOException
      Throws:
      IOException

    • getMissingValue

      public Object getMissingValue()
      Return the value to use for documents that don't have a value. A value of null indicates that default should be used.

    • setMissingValue

      public void setMissingValue(Object missingValue)
      Set the value to use for documents that don't have a value.

    • initFieldType

      private void initFieldType(String field, SortField.Type type)

    • getField

      public String getField()
      Returns the name of the field. Could return null if the sort is by SCORE or DOC.
      Returns:
      Name of field, possibly null.

    • getType

      public SortField.Type getType()
      Returns the type of contents in the field.
      Returns:
      One of the constants SCORE, DOC, STRING, INT or FLOAT.

    • getReverse

      public boolean getReverse()
      Returns whether the sort should be reversed.
      Returns:
      True if natural order should be reversed.

    • getComparatorSource

      public FieldComparatorSource getComparatorSource()
      Returns the FieldComparatorSource used for custom sorting

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • setCanUsePoints

      public void setCanUsePoints()
      For numeric sort fields, setting this field, indicates that the same numeric data has been indexed with two fields: doc values and points and that these fields have the same name. This allows to use sort optimization and skip non-competitive documents.

    • getCanUsePoints

      public boolean getCanUsePoints()

    • equals

      public boolean equals(Object o)
      Returns true if o is equal to this. If a FieldComparatorSource was provided, it must properly implement equals (unless a singleton is always used). canUsePoints field is not part of equals and hasCode intentionally, as it is only useful during search-time and using it in these functions prevents index sorting optimizations that rely on the equality of the index-time and search-time SortField instances.
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Returns a hash code for this SortField instance. If a FieldComparatorSource was provided, it must properly implement hashCode (unless a singleton is always used).
      Overrides:
      hashCode in class Object

    • setBytesComparator

      public void setBytesComparator(Comparator<BytesRef> b)

    • getBytesComparator

      public Comparator<BytesRef> getBytesComparator()

    • getComparator

      public FieldComparator<?> getComparator(int numHits, int sortPos)
      Returns the FieldComparator to use for sorting.
      Parameters:
      numHits - number of top hits the queue will store
      sortPos - position of this SortField within Sort. The comparator is primary if sortPos==0, secondary if sortPos==1, etc. Some comparators can optimize themselves when they are the primary sort.
      Returns:
      FieldComparator to use when sorting

    • rewrite

      public SortField rewrite(IndexSearcher searcher) throws IOException
      Rewrites this SortField, returning a new SortField if a change is made. Subclasses should override this define their rewriting behavior when this SortField is of type SortField.Type.REWRITEABLE
      Parameters:
      searcher - IndexSearcher to use during rewriting
      Returns:
      New rewritten SortField, or this if nothing has changed.
      Throws:
      IOException - Can be thrown by the rewriting

    • needsScores

      public boolean needsScores()
      Whether the relevance score is needed to sort documents.

    • getIndexSorter

      public IndexSorter getIndexSorter()
      Returns an IndexSorter used for sorting index segments by this SortField. If the SortField cannot be used for index sorting (for example, if it uses scores or other query-dependent values) then this method should return null SortFields that implement this method should also implement a companion SortFieldProvider to serialize and deserialize the sort in index segment headers