org.apache.lucene.search.grouping
Class AbstractAllGroupHeadsCollector<GH extends AbstractAllGroupHeadsCollector.GroupHead>

java.lang.Object
  extended by org.apache.lucene.search.Collector
      extended by org.apache.lucene.search.grouping.AbstractAllGroupHeadsCollector<GH>
Direct Known Subclasses:
FunctionAllGroupHeadsCollector, TermAllGroupHeadsCollector

public abstract class AbstractAllGroupHeadsCollector<GH extends AbstractAllGroupHeadsCollector.GroupHead>
extends Collector

This collector specializes in collecting the most relevant document (group head) for each group that match the query.

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

Nested Class Summary
static class AbstractAllGroupHeadsCollector.GroupHead<GROUP_VALUE_TYPE>
          Represents a group head.
protected  class AbstractAllGroupHeadsCollector.TemporalResult
          Contains the result of group head retrieval.
 
Field Summary
protected  int compIDXEnd
           
protected  int[] reversed
           
protected  AbstractAllGroupHeadsCollector.TemporalResult temporalResult
           
 
Constructor Summary
protected AbstractAllGroupHeadsCollector(int numberOfSorts)
           
 
Method Summary
 boolean acceptsDocsOutOfOrder()
           
 void collect(int doc)
           
protected abstract  Collection<GH> getCollectedGroupHeads()
          Returns the collected group heads.
 int groupHeadsSize()
           
protected abstract  void retrieveGroupHeadAndAddIfNotExist(int doc)
          Returns the group head and puts it into temporalResult.
 int[] retrieveGroupHeads()
           
 FixedBitSet retrieveGroupHeads(int maxDoc)
           
 
Methods inherited from class org.apache.lucene.search.Collector
setNextReader, setScorer
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

reversed

protected final int[] reversed

compIDXEnd

protected final int compIDXEnd

temporalResult

protected final AbstractAllGroupHeadsCollector.TemporalResult temporalResult
Constructor Detail

AbstractAllGroupHeadsCollector

protected AbstractAllGroupHeadsCollector(int numberOfSorts)
Method Detail

retrieveGroupHeads

public FixedBitSet retrieveGroupHeads(int maxDoc)
Parameters:
maxDoc - The maxDoc of the top level IndexReader.
Returns:
an FixedBitSet containing all group heads.

retrieveGroupHeads

public int[] retrieveGroupHeads()
Returns:
an int array containing all group heads. The size of the array is equal to number of collected unique groups.

groupHeadsSize

public int groupHeadsSize()
Returns:
the number of group heads found for a query.

retrieveGroupHeadAndAddIfNotExist

protected abstract void retrieveGroupHeadAndAddIfNotExist(int doc)
                                                   throws IOException
Returns the group head and puts it into temporalResult. If the group head wasn't encountered before then it will be added to the collected group heads.

The AbstractAllGroupHeadsCollector.TemporalResult.stop property will be true if the group head wasn't encountered before otherwise false.

Parameters:
doc - The document to retrieve the group head for.
Throws:
IOException - If I/O related errors occur

getCollectedGroupHeads

protected abstract Collection<GH> getCollectedGroupHeads()
Returns the collected group heads. Subsequent calls should return the same group heads.

Returns:
the collected group heads

collect

public void collect(int doc)
             throws IOException
Specified by:
collect in class Collector
Throws:
IOException

acceptsDocsOutOfOrder

public boolean acceptsDocsOutOfOrder()
Specified by:
acceptsDocsOutOfOrder in class Collector


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