Class EarlyTerminatingSortingCollector

A Lucene.Net.Search.ICollector that early terminates collection of documents on a per-segment basis, if the segment was sorted according to the given Lucene.Net.Search.Sort.

NOTE: the Lucene.Net.Search.ICollector detects sorted segments according to SortingMergePolicy, so it's best used in conjunction with it. Also, it collects up to a specified m_numDocsToCollect from each segment, and therefore is mostly suitable for use in conjunction with collectors such as Lucene.Net.Search.TopDocsCollector<T>, and not e.g. Lucene.Net.Search.TotalHitCountCollector.

NOTE: If you wrap a Lucene.Net.Search.TopDocsCollector<T> that sorts in the same order as the index order, the returned TopDocs will be correct. However the total of Lucene.Net.Search.TopDocsCollector<T>.TotalHits hit count will be underestimated since not all matching documents will have been collected.

NOTE: This Lucene.Net.Search.ICollector uses Lucene.Net.Search.Sort.ToString() to detect whether a segment was sorted with the same Lucene.Net.Search.Sort. This has two implications:

if a custom comparer is not implemented correctly and returns different identifiers for equivalent instances, this collector will not detect sorted segments,
if you suddenly change the Lucene.Net.Index.IndexWriter's SortingMergePolicy to sort according to another criterion and if both the old and the new Lucene.Net.Search.Sorts have the same identifier, this Lucene.Net.Search.ICollector will incorrectly detect sorted segments.

Note

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

Inheritance

object

EarlyTerminatingSortingCollector

Implements

ICollector

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Lucene.Net.Index.Sorter

Assembly: Lucene.Net.Misc.dll

Syntax

public class EarlyTerminatingSortingCollector : ICollector

Constructors

EarlyTerminatingSortingCollector(ICollector, Sort, int)

Create a new EarlyTerminatingSortingCollector instance.

Declaration

public EarlyTerminatingSortingCollector(ICollector @in, Sort sort, int numDocsToCollect)

Parameters

Type	Name	Description
ICollector	in	the collector to wrap
Sort	sort	the sort you are sorting the search results on
int	numDocsToCollect	the number of documents to collect on each segment. When wrapping a Lucene.Net.Search.TopDocsCollector<T>, this number should be the number of hits.

Fields

m_in

The wrapped Collector

Declaration

protected readonly ICollector m_in

Field Value

Type	Description
ICollector

m_numDocsToCollect

Number of documents to collect in each segment

Declaration

protected readonly int m_numDocsToCollect

Field Value

Type	Description
int

m_segmentSorted

True if the current segment being processed is sorted by Lucene.Net.Search.Sort.Sort()

Declaration

protected bool m_segmentSorted

Field Value

Type	Description
bool

m_segmentTotalCollect

Number of documents to collect in the current segment being processed

Declaration

protected int m_segmentTotalCollect

Field Value

Type	Description
int

m_sort

Sort used to sort the search results

Declaration

protected readonly Sort m_sort

Field Value

Type	Description
Sort

Properties

AcceptsDocsOutOfOrder

Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to Collect(int).

Most Lucene Query implementations will visit matching docIDs in order. However, some queries (currently limited to certain cases of Lucene.Net.Search.BooleanQuery) can achieve faster searching if the Lucene.Net.Search.ICollector allows them to deliver the docIDs out of order.

Many collectors don't mind getting docIDs out of order, so it's important to return true here.

Declaration

public virtual bool AcceptsDocsOutOfOrder { get; }

Property Value

Type	Description
bool

Methods

Collect(int)

Called once for every document matching a query, with the unbased document number.

Note: The collection of the current segment can be terminated by throwing a Lucene.Net.Search.CollectionTerminatedException. In this case, the last docs of the current Lucene.Net.Index.AtomicReaderContext will be skipped and Lucene.Net.Search.IndexSearcher will swallow the exception and continue collection with the next leaf.

Note: this is called in an inner search loop. For good search performance, implementations of this method should not call Doc(int) or Document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

Declaration

public virtual void Collect(int doc)

Parameters

Type	Name	Description
int	doc

SetNextReader(AtomicReaderContext)

Called before collecting from each Lucene.Net.Index.AtomicReaderContext. All doc ids in Collect(int) will correspond to Lucene.Net.Index.IndexReaderContext.Reader.

Add Lucene.Net.Index.AtomicReaderContext.DocBase to the current Lucene.Net.Index.IndexReaderContext.Reader's internal document id to re-base ids in Collect(int).

Declaration

public virtual void SetNextReader(AtomicReaderContext context)

Parameters

Type	Name	Description
AtomicReaderContext	context	next atomic reader context

SetScorer(Scorer)

Called before successive calls to Collect(int). Implementations that need the score of the current document (passed-in to Collect(int)), should save the passed-in Lucene.Net.Search.Scorer and call scorer.GetScore() when needed.

Declaration

public virtual void SetScorer(Scorer scorer)

Parameters

Type	Name	Description
Scorer	scorer

Implements

Lucene.Net.Search.ICollector