Package org.apache.lucene.search

Class SortField

java.lang.Object
org.apache.lucene.search.SortField
Direct Known Subclasses:
SortedNumericSortField, SortedSetSortField
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.

Sorting on a numeric field that is indexed with both doc values and points may use an optimization to skip non-competitive documents. This optimization relies on the assumption that the same data is stored in these points and doc values.

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

Since:
lucene 1.4
See Also:

  • Field Details

    • FIELD_SCORE

      public static final SortField FIELD_SCORE
      Represents sorting by document score (relevance).

    • FIELD_DOC

      public static final SortField FIELD_DOC
      Represents sorting by document number (index order).

    • missingValue

      protected Object missingValue

    • STRING_FIRST

      public static final Object STRING_FIRST
      Pass this to setMissingValue(java.lang.Object) to have missing string values sort first.

    • STRING_LAST

      public static final Object STRING_LAST
      Pass this to setMissingValue(java.lang.Object) to have missing string values sort last.

  • 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

    • 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.

    • 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

    • 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).
      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, boolean enableSkipping)
      Returns the FieldComparator to use for sorting.
      Parameters:
      numHits - number of top hits the queue will store
      enableSkipping - true if the comparator can skip documents via LeafFieldComparator.competitiveIterator()
      Returns:
      FieldComparator to use when sorting
      WARNING: This API is experimental and might change in incompatible ways in the next release.

    • 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
      WARNING: This API is experimental and might change in incompatible ways in the next release.

    • 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

      WARNING: This API is experimental and might change in incompatible ways in the next release.

    • setOptimizeSortWithPoints

      @Deprecated public void setOptimizeSortWithPoints(boolean optimizeSortWithPoints)
      Deprecated.
      should only be used for compatibility with 8.x indices that got created with inconsistent data across fields, or the wrong sort configuration in the index sort
      Enables/disables numeric sort optimization to use the Points index.

      Enabled by default. By default, sorting on a numeric field activates point sort optimization that can efficiently skip over non-competitive hits. Sort optimization has a number of requirements, one of which is that SortField.Type matches the Point type with which the field was indexed (e.g. sort on IntPoint field should use SortField.Type.INT). Another requirement is that the same data is indexed with points and doc values for the field.

      Parameters:
      optimizeSortWithPoints - providing false disables the optimization, in cases where these requirements can't be met.

    • getOptimizeSortWithPoints

      @Deprecated public boolean getOptimizeSortWithPoints()
      Deprecated.
      Returns whether sort optimization should be optimized with points index
      Returns:
      whether sort optimization should be optimized with points index