org.apache.lucene.sandbox.queries

Class SortedSetSortField

java.lang.Object

org.apache.lucene.search.SortField

org.apache.lucene.sandbox.queries.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 (see below) 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).

Limitations:

• Fields containing Integer.MAX_VALUE or more unique values are unsupported.
• Selectors other than the default (SortedSetSortField.Selector.MIN) require optional codec support. However several codecs provided by Lucene, including the current default codec, support this.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SortedSetSortField.Selector Selects a value from the document's set to use as the sort value

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

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj)
FieldComparator<?>	getComparator(int numHits, int sortPos)
SortedSetSortField.Selector	getSelector() Returns the selector in use for this sort
int	hashCode()
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, getComparatorSource, getField, getParser, getReverse, getType, needsScores, rewrite, setBytesComparator

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,
                  SortedSetSortField.Selector 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 for choosing the sort value from the set.

NOTE: selectors other than SortedSetSortField.Selector.MIN require optional codec support.

Method Detail

getSelector

public SortedSetSortField.Selector getSelector()

Returns the selector in use for this sort

hashCode

public int hashCode()

Overrides:

hashCode in class SortField

equals

public boolean equals(Object obj)

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)
                                 throws IOException

Overrides:

getComparator in class SortField

Throws:

IOException