Class AbstractAllGroupsCollector<TGroupValue>

A collector that collects all groups that match the query. Only the group value is collected, and the order is undefined. This collector does not determine the most relevant document of a group.

This is an abstract version. Concrete implementations define what a group actually is and how it is internally collected.

Note

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

Inheritance
object
AbstractAllGroupsCollector<TGroupValue>
FunctionAllGroupsCollector<TMutableValue>
TermAllGroupsCollector
Implements
ICollector
Inherited Members
Namespace: Lucene.Net.Search.Grouping
Assembly: Lucene.Net.Grouping.dll
Syntax
public abstract class AbstractAllGroupsCollector<TGroupValue> : IAbstractAllGroupsCollector<TGroupValue>, ICollector
Type Parameters
Name Description
TGroupValue

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

GroupCount

Returns the total number of groups for the executed search. This is a convenience method. The following code snippet has the same effect: 

GetGroups().Count
Declaration
public virtual int GroupCount { get; }
Property Value
Type Description
int

The total number of groups for the executed search

Groups

Returns the group values

This is an unordered collections of group values. For each group that matched the query there is a Lucene.Net.Util.BytesRef representing a group value.

Declaration
public abstract IEnumerable<TGroupValue> Groups { get; }
Property Value
Type Description
IEnumerable<TGroupValue>

the group values

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

Implements

Lucene.Net.Search.ICollector