Class AbstractFirstPassGroupingCollector<TGroupValue>

FirstPassGroupingCollector is the first of two passes necessary to collect grouped hits. This pass gathers the top N sorted groups. Concrete subclasses define what a group is and how it is internally collected.

See org.apache.lucene.search.grouping for more details including a full code example.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Inheritance
System.Object
AbstractFirstPassGroupingCollector<TGroupValue>
FunctionFirstPassGroupingCollector
TermFirstPassGroupingCollector
Namespace: Lucene.Net.Search.Grouping
Assembly: Lucene.Net.Grouping.dll
Syntax
public abstract class AbstractFirstPassGroupingCollector<TGroupValue> : object, IAbstractFirstPassGroupingCollector<TGroupValue>, ICollector
Type Parameters
Name Description
TGroupValue

Constructors

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AbstractFirstPassGroupingCollector(Sort, Int32)

Create the first pass collector.

Declaration
public AbstractFirstPassGroupingCollector(Sort groupSort, int topNGroups)
Parameters
Type Name Description
Sort groupSort

The Sort used to sort the groups. The top sorted document within each group according to groupSort, determines how that group sorts against other groups. This must be non-null, ie, if you want to groupSort by relevance use Sort.RELEVANCE.
System.Int32 topNGroups

How many top groups to keep.

Fields

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m_orderedGroups

Declaration
protected SortedSet<CollectedSearchGroup<TGroupValue>> m_orderedGroups
Field Value
Type Description
SortedSet<CollectedSearchGroup<TGroupValue>>

Properties

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AcceptsDocsOutOfOrder

Declaration
public virtual bool AcceptsDocsOutOfOrder { get; }
Property Value
Type Description
System.Boolean

Methods

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Collect(Int32)

Declaration
public virtual void Collect(int doc)
Parameters
Type Name Description
System.Int32 doc
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CopyDocGroupValue(TGroupValue, TGroupValue)

Returns a copy of the specified group value by creating a new instance and copying the value from the specified groupValue in the new instance. Or optionally the reuse argument can be used to copy the group value in.

Declaration
protected abstract TGroupValue CopyDocGroupValue(TGroupValue groupValue, TGroupValue reuse)
Parameters
Type Name Description
TGroupValue groupValue

The group value to copy
TGroupValue reuse

Optionally a reuse instance to prevent a new instance creation
Returns
Type Description
TGroupValue

a copy of the specified group value
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GetDocGroupValue(Int32)

Returns the group value for the specified doc.

Declaration
protected abstract TGroupValue GetDocGroupValue(int doc)
Parameters
Type Name Description
System.Int32 doc

The specified doc
Returns
Type Description
TGroupValue

the group value for the specified doc
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GetTopGroups(Int32, Boolean)

Returns top groups, starting from offset. This may return null, if no groups were collected, or if the number of unique groups collected is <= offset.

Declaration
public virtual IEnumerable<ISearchGroup<TGroupValue>> GetTopGroups(int groupOffset, bool fillFields)
Parameters
Type Name Description
System.Int32 groupOffset

The offset in the collected groups
System.Boolean fillFields

Whether to fill to SortValues
Returns
Type Description
IEnumerable<ISearchGroup<TGroupValue>>

top groups, starting from offset
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SetNextReader(AtomicReaderContext)

Declaration
public virtual void SetNextReader(AtomicReaderContext context)
Parameters
Type Name Description
AtomicReaderContext context
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SetScorer(Scorer)

Declaration
public virtual void SetScorer(Scorer scorer)
Parameters
Type Name Description
Scorer scorer

Implements