Package org.apache.lucene.search

Class TopFieldCollectorManager

java.lang.Object

org.apache.lucene.search.TopFieldCollectorManager

All Implemented Interfaces:

CollectorManager<TopFieldCollector,TopFieldDocs>

public class TopFieldCollectorManager
extends Object
implements CollectorManager<TopFieldCollector,TopFieldDocs>

Create a TopFieldCollectorManager which uses a shared hit counter to maintain number of hits and a shared MaxScoreAccumulator to propagate the minimum score across segments if the primary sort is by relevancy.

Note that a new collectorManager should be created for each search due to its internal states.

Constructor Summary

Constructors

Constructor	Description
TopFieldCollectorManager(Sort sort, int numHits, int totalHitsThreshold)	Creates a new TopFieldCollectorManager from the given arguments, with thread-safe internal states.
TopFieldCollectorManager(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold)	Creates a new TopFieldCollectorManager from the given arguments.
TopFieldCollectorManager(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold, boolean supportsConcurrency)	Deprecated. Use TopFieldCollectorManager(Sort, int, FieldDoc, int), the supportsConcurrency parameter is now a no-op.

Method Summary

Modifier and Type	Method	Description
List<TopFieldCollector>	getCollectors()	Deprecated. This method will be removed in Lucene 11.
TopFieldCollector	newCollector()	Return a new Collector.
TopFieldDocs	reduce(Collection<TopFieldCollector> collectors)	Reduce the results of individual collectors into a meaningful result.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

TopFieldCollectorManager

@Deprecated
public TopFieldCollectorManager(Sort sort,
 int numHits,
 FieldDoc after,
 int totalHitsThreshold,
 boolean supportsConcurrency)

Deprecated.

Use TopFieldCollectorManager(Sort, int, FieldDoc, int), the supportsConcurrency parameter is now a no-op.

Creates a new TopFieldCollectorManager from the given arguments.

NOTE: The instances returned by this method pre-allocate a full array of length numHits.

Parameters:

sort - the sort criteria (SortFields).

numHits - the number of results to collect.

after - the previous doc after which matching docs will be collected.

totalHitsThreshold - the number of docs to count accurately. If the query matches more than totalHitsThreshold hits then its hit count will be a lower bound. On the other hand if the query matches less than or exactly totalHitsThreshold hits then the hit count of the result will be accurate. Integer.MAX_VALUE may be used to make the hit count accurate, but this will also make query processing slower.

supportsConcurrency - to use thread-safe and slower internal states for count tracking.

TopFieldCollectorManager

public TopFieldCollectorManager(Sort sort,
 int numHits,
 FieldDoc after,
 int totalHitsThreshold)

Creates a new TopFieldCollectorManager from the given arguments.

Thread safety is guaranteed for the shared internal states (hit counting, minimum score propagation) across collectors created by newCollector(). Note that newCollector() itself is designed to be called from a single thread; IndexSearcher handles this by calling it sequentially before parallel slice execution.

NOTE: The instances returned by this method pre-allocate a full array of length numHits.

Parameters:

sort - the sort criteria (SortFields).

numHits - the number of results to collect.

after - the previous doc after which matching docs will be collected.

totalHitsThreshold - the number of docs to count accurately. If the query matches more than totalHitsThreshold hits then its hit count will be a lower bound. On the other hand if the query matches less than or exactly totalHitsThreshold hits then the hit count of the result will be accurate. Integer.MAX_VALUE may be used to make the hit count accurate, but this will also make query processing slower.

TopFieldCollectorManager

public TopFieldCollectorManager(Sort sort,
 int numHits,
 int totalHitsThreshold)

Creates a new TopFieldCollectorManager from the given arguments, with thread-safe internal states.

NOTE: The instances returned by this method pre-allocate a full array of length numHits.

Parameters:

sort - the sort criteria (SortFields).

numHits - the number of results to collect.

totalHitsThreshold - the number of docs to count accurately. If the query matches more than totalHitsThreshold hits then its hit count will be a lower bound. On the other hand if the query matches less than or exactly totalHitsThreshold hits then the hit count of the result will be accurate. Integer.MAX_VALUE may be used to make the hit count accurate, but this will also make query processing slower.

Method Details

newCollector

public TopFieldCollector newCollector()

Description copied from interface: CollectorManager

Return a new Collector. This must return a different instance on each call.

Specified by:

newCollector in interface CollectorManager<TopFieldCollector,TopFieldDocs>

reduce

public TopFieldDocs reduce(Collection<TopFieldCollector> collectors)
                    throws IOException

Description copied from interface: CollectorManager

Reduce the results of individual collectors into a meaningful result. For instance a TopDocsCollector would compute the top docs of each collector and then merge them using TopDocs.merge(int, TopDocs[]). This method must be called after collection is finished on all provided collectors.

Specified by:

reduce in interface CollectorManager<TopFieldCollector,TopFieldDocs>

Throws:

IOException

getCollectors

@Deprecated
public List<TopFieldCollector> getCollectors()

Deprecated.

This method will be removed in Lucene 11. All needed information, including early termination, is available in the TopFieldDocs returned by reduction.

Returns the collectors created by this manager.