Class TopDocsCollector<T>

A base class for all collectors that return a TopDocs output. This collector allows easy extension by providing a single constructor which accepts a Lucene.Net.Util.PriorityQueue<T> as well as protected members for that priority queue and a counter of the number of total hits.
Extending classes can override TopDocs(Int32, Int32) and TotalHits in order to provide their own implementation.

Inheritance
System.Object
Collector
TopDocsCollector<T>
TopFieldCollector
TopScoreDocCollector
Inherited Members
Namespace:
Assembly: Lucene.Net.NetCore.dll
Syntax
public abstract class TopDocsCollector<T> : Collector where T : ScoreDoc
Type Parameters
Name Description
T

Constructors

Name Description
TopDocsCollector(PriorityQueue<T>)

Fields

Name Description
EMPTY_TOPDOCS
internalTotalHits

The total number of documents that the collector encountered.

pq

The priority queue which holds the top documents. Note that different implementations of PriorityQueue give different meaning to 'top documents'. HitQueue for example aggregates the top scoring documents, while other PQ implementations may hold documents sorted by other criteria.

Properties

Name Description
TotalHits

The total number of documents that matched this query.

Methods

Name Description
NewTopDocs(ScoreDoc[], Int32)

Returns a TopDocs instance containing the given results. If results is null it means there are no results to return, either because there were 0 calls to collect() or because the arguments to topDocs were invalid.
PopulateResults(ScoreDoc[], Int32)

Populates the results array with the ScoreDoc instaces. This can be overridden in case a different ScoreDoc type should be returned.
TopDocs()

Returns the top docs that were collected by this collector.

TopDocs(Int32)

Returns the documents in the rage [start .. pq.size()) that were collected by this collector. Note that if start >= pq.size(), an empty TopDocs is returned.
This method is convenient to call if the application allways asks for the last results, starting from the last 'page'.
NOTE: you cannot call this method more than once for each search execution. If you need to call it more than once, passing each time a different start, you should call TopDocs() and work with the returned TopDocs object, which will contain all the results this search execution collected.
TopDocs(Int32, Int32)

Returns the documents in the rage [start .. start+howMany) that were collected by this collector. Note that if start >= pq.size(), an empty TopDocs is returned, and if pq.size() - start < howMany, then only the available documents in [start .. pq.size()) are returned.
This method is useful to call in case pagination of search results is allowed by the search application, as well as it attempts to optimize the memory used by allocating only as much as requested by howMany.
NOTE: you cannot call this method more than once for each search execution. If you need to call it more than once, passing each time a different range, you should call TopDocs() and work with the returned TopDocs object, which will contain all the results this search execution collected.