org.apache.lucene.search

Class SortedSetSortField

java.lang.Object

org.apache.lucene.search.SortField

org.apache.lucene.search.SortedSetSortField

public class SortedSetSortField
extends SortField

SortField for SortedSetDocValues.

A SortedSetDocValues contains multiple values for a field, so sorting with this technique "selects" a value as the representative sort value for the document.

By default, the minimum value in the set is selected as the sort value, but this can be customized. Selectors other than the default do have some limitations to ensure that all selections happen in constant-time for performance.

Like sorting by string, this also supports sorting missing values as first or last, via setMissingValue(Object).

See Also:

SortedSetSelector

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SortedSetSortField.Provider A SortFieldProvider for this sort

Nested classes/interfaces inherited from class org.apache.lucene.search.SortField

SortField.Type

Field Summary

Fields inherited from class org.apache.lucene.search.SortField

FIELD_DOC, FIELD_SCORE, missingValue, STRING_FIRST, STRING_LAST

Constructor Summary

Constructors

Constructor and Description
SortedSetSortField(String field, boolean reverse) Creates a sort, possibly in reverse, by the minimum value in the set for the document.
SortedSetSortField(String field, boolean reverse, SortedSetSelector.Type selector) Creates a sort, possibly in reverse, specifying how the sort value from the document's set is selected.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj) Returns true if o is equal to this.
FieldComparator<?>	getComparator(int numHits, int sortPos) Returns the FieldComparator to use for sorting.
IndexSorter	getIndexSorter() Returns an IndexSorter used for sorting index segments by this SortField.
SortedSetSelector.Type	getSelector() Returns the selector in use for this sort
int	hashCode() Returns a hash code for this SortField instance.
void	setMissingValue(Object missingValue) Set how missing values (the empty set) are sorted.
String	toString()

Methods inherited from class org.apache.lucene.search.SortField

getBytesComparator, getCanUsePoints, getComparatorSource, getField, getMissingValue, getReverse, getType, needsScores, readType, rewrite, setBytesComparator, setCanUsePoints

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SortedSetSortField

public SortedSetSortField(String field,
                          boolean reverse)

Creates a sort, possibly in reverse, by the minimum value in the set for the document.

Parameters:

field - Name of field to sort by. Must not be null.

reverse - True if natural order should be reversed.

SortedSetSortField

public SortedSetSortField(String field,
                          boolean reverse,
                          SortedSetSelector.Type selector)

Creates a sort, possibly in reverse, specifying how the sort value from the document's set is selected.

Parameters:

field - Name of field to sort by. Must not be null.

reverse - True if natural order should be reversed.

selector - custom selector type for choosing the sort value from the set.

NOTE: selectors other than SortedSetSelector.Type.MIN require optional codec support.

Method Detail

getSelector

public SortedSetSelector.Type getSelector()

Returns the selector in use for this sort

hashCode

public int hashCode()

Description copied from class: SortField

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 SortField

equals

public boolean equals(Object obj)

Description copied from class: SortField

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 SortField

toString

public String toString()

Overrides:

toString in class SortField

setMissingValue

public void setMissingValue(Object missingValue)

Set how missing values (the empty set) are sorted.

Note that this must be SortField.STRING_FIRST or SortField.STRING_LAST.

Overrides:

setMissingValue in class SortField

getComparator

public FieldComparator<?> getComparator(int numHits,
                                        int sortPos)

Description copied from class: SortField

Returns the FieldComparator to use for sorting.

Overrides:

getComparator in class SortField

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

getIndexSorter

public IndexSorter getIndexSorter()

Description copied from class: SortField

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

Overrides:

getIndexSorter in class SortField