Class AbstractDistinctValuesCollector<GC>
A second pass grouping collector that keeps track of distinct values for a specified field for the top N group.
Note
This API is experimental and might change in incompatible ways in the next release.
Inheritance
Inherited Members
Namespace: Lucene.Net.Search.Grouping
Assembly: Lucene.Net.Grouping.dll
Syntax
public abstract class AbstractDistinctValuesCollector<GC> : IAbstractDistinctValuesCollector<GC>, ICollector where GC : AbstractDistinctValuesCollector.IGroupCount<object>Type Parameters
| Name | Description |
|---|---|
| GC |
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 |
Groups
Returns all unique values for each top N group.
Declaration
public abstract IEnumerable<GC> Groups { get; }Property Value
| Type | Description |
|---|---|
| IEnumerable<GC> | all unique values for each top N group |
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 abstract 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 abstract 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 |