Class TermAllGroupsCollector

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.

Implementation detail: an int hash set (SentinelIntSet) is used to detect if a group is already added to the total count. For each segment the int set is cleared and filled with previous counted groups that occur in the new segment.

Note

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

Inheritance
object
AbstractAllGroupsCollector<BytesRef>
TermAllGroupsCollector
Implements
ICollector
Inherited Members
Namespace: Lucene.Net.Search.Grouping.Terms
Assembly: Lucene.Net.Grouping.dll
Syntax
public class TermAllGroupsCollector : AbstractAllGroupsCollector<BytesRef>, IAbstractAllGroupsCollector<BytesRef>, ICollector

Constructors

TermAllGroupsCollector(string)

Constructs a AbstractAllGroupsCollector<TGroupValue>. This sets the initial allocation size for the internal int set and group list to 128.

Declaration
public TermAllGroupsCollector(string groupField)
Parameters
Type Name Description
string groupField

The field to group by

TermAllGroupsCollector(string, int)

Expert: Constructs a AbstractAllGroupsCollector<TGroupValue>

Declaration
public TermAllGroupsCollector(string groupField, int initialSize)
Parameters
Type Name Description
string groupField

The field to group by
int initialSize

The initial allocation size of the internal int set and group list which should roughly match the total number of expected unique groups. Be aware that the heap usage is 4 bytes * initialSize.

Properties

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 override IEnumerable<BytesRef> Groups { get; }
Property Value
Type Description
IEnumerable<BytesRef>

the group values
Overrides

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 override void Collect(int doc)
Parameters
Type Name Description
int doc
Overrides

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 override void SetNextReader(AtomicReaderContext context)
Parameters
Type Name Description
AtomicReaderContext context

next atomic reader context
Overrides

Implements

Lucene.Net.Search.ICollector