java.lang.Object
- org.apache.lucene.search.Collector
- - org.apache.lucene.search.grouping.AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>

Direct Known Subclasses:

TermSecondPassGroupingCollector
```
public abstract class AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>
extends Collector
```
SecondPassGroupingCollector is the second of two passes necessary to collect grouped docs. This pass gathers the top N documents per top group computed from the first pass. 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.

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

Nested Class Summary

Nested Classes
Modifier and Type Class Description

class AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>

Field Summary

Fields
Modifier and Type	Field	Description
`protected AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>[]`	`groupDocs`
`protected Map<GROUP_VALUE_TYPE,AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>>`	`groupMap`

Constructor Summary

Constructors
Constructor	Description
`AbstractSecondPassGroupingCollector(Collection<SearchGroup<GROUP_VALUE_TYPE>> groups, Sort groupSort, Sort withinGroupSort, int maxDocsPerGroup, boolean getScores, boolean getMaxScores, boolean fillSortFields)`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`acceptsDocsOutOfOrder()`	Return `true` if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to `Collector.collect(int)`.
`void`	`collect(int doc)`	Called once for every document matching a query, with the unbased document number.
`TopGroups<GROUP_VALUE_TYPE>`	`getTopGroups(int withinGroupOffset)`
`protected abstract AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>`	`retrieveGroup(int doc)`	Returns the group the specified doc belongs to or `null` if no group could be retrieved.
`void`	`setNextReader(IndexReader reader, int docBase)`	Called before collecting from each IndexReader.
`void`	`setScorer(Scorer scorer)`	Called before successive calls to `Collector.collect(int)`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - groupMap
```
protected final Map<GROUP_VALUE_TYPE,AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>> groupMap
```
  - groupDocs
```
protected AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>[] groupDocs
```
- Constructor Detail
  - AbstractSecondPassGroupingCollector
```
public AbstractSecondPassGroupingCollector(Collection<SearchGroup<GROUP_VALUE_TYPE>> groups,
                                           Sort groupSort,
                                           Sort withinGroupSort,
                                           int maxDocsPerGroup,
                                           boolean getScores,
                                           boolean getMaxScores,
                                           boolean fillSortFields)
                                    throws IOException
```
    Throws:
    
    IOException
- Method Detail
  - setScorer
```
public void setScorer(Scorer scorer)
               throws IOException
```
    Description copied from class: Collector
    
    Called before successive calls to Collector.collect(int). Implementations that need the score of the current document (passed-in to Collector.collect(int)), should save the passed-in Scorer and call scorer.score() when needed.
    
    Specified by:
    
    setScorer in class Collector
    
    Throws:
    
    IOException
  - collect
```
public void collect(int doc)
             throws IOException
```
    Description copied from class: Collector
    
    Called once for every document matching a query, with the unbased document number.
    Note: This is called in an inner search loop. For good search performance, implementations of this method should not call Searcher.doc(int) or IndexReader.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.
    
    Specified by:
    
    collect in class Collector
    
    Throws:
    
    IOException
  - retrieveGroup
```
protected abstract AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE> retrieveGroup(int doc)
                                                                                                throws IOException
```
    Returns the group the specified doc belongs to or null if no group could be retrieved.
    
    Parameters:
    
    doc - The specified doc
    
    Returns:
    
    the group the specified doc belongs to or null if no group could be retrieved
    
    Throws:
    
    IOException - If an I/O related error occurred
  - setNextReader
```
public void setNextReader(IndexReader reader,
                          int docBase)
                   throws IOException
```
    Description copied from class: Collector
    
    Called before collecting from each IndexReader. All doc ids in Collector.collect(int) will correspond to reader. Add docBase to the current IndexReaders internal document id to re-base ids in Collector.collect(int).
    
    Specified by:
    
    setNextReader in class Collector
    
    Parameters:
    
    reader - next IndexReader
    
    Throws:
    
    IOException
  - acceptsDocsOutOfOrder
```
public boolean acceptsDocsOutOfOrder()
```
    Description copied from class: Collector
    
    Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to Collector.collect(int).
    Most Lucene Query implementations will visit matching docIDs in order. However, some queries (currently limited to certain cases of BooleanQuery) can achieve faster searching if the Collector 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.
    
    Specified by:
    
    acceptsDocsOutOfOrder in class Collector
  - getTopGroups
```
public TopGroups<GROUP_VALUE_TYPE> getTopGroups(int withinGroupOffset)
```

Class AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

groupMap

groupDocs

Constructor Detail

AbstractSecondPassGroupingCollector

Method Detail

setScorer

collect

retrieveGroup

setNextReader

acceptsDocsOutOfOrder

getTopGroups