Module org.apache.lucene.grouping
Class FirstPassGroupingCollector<T>
- java.lang.Object
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- org.apache.lucene.search.SimpleCollector
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- org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
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- All Implemented Interfaces:
Collector
,LeafCollector
public class FirstPassGroupingCollector<T> extends SimpleCollector
FirstPassGroupingCollector is the first of two passes necessary to collect grouped hits. This pass gathers the top N sorted groups. Groups are defined by aGroupSelector
See
org.apache.lucene.search.grouping
for more details including a full code example.
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Field Summary
Fields Modifier and Type Field Description private FieldComparator<?>[]
comparators
private int
compIDXEnd
private int
docBase
private java.util.HashMap<T,CollectedSearchGroup<T>>
groupMap
private GroupSelector<T>
groupSelector
private LeafFieldComparator[]
leafComparators
private boolean
needsScores
protected java.util.TreeSet<CollectedSearchGroup<T>>
orderedGroups
private int[]
reversed
private int
spareSlot
private int
topNGroups
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Constructor Summary
Constructors Constructor Description FirstPassGroupingCollector(GroupSelector<T> groupSelector, Sort groupSort, int topNGroups)
Create the first pass collector.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private void
buildSortedSet()
void
collect(int doc)
Called once for every document matching a query, with the unbased document number.protected void
doSetNextReader(LeafReaderContext readerContext)
This method is called before collectingcontext
.GroupSelector<T>
getGroupSelector()
java.util.Collection<SearchGroup<T>>
getTopGroups(int groupOffset)
Returns top groups, starting from offset.private boolean
isCompetitive(int doc)
ScoreMode
scoreMode()
Indicates what features are required from the scorer.void
setScorer(Scorable scorer)
Called before successive calls toLeafCollector.collect(int)
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Methods inherited from class org.apache.lucene.search.SimpleCollector
getLeafCollector
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.apache.lucene.search.LeafCollector
collect, competitiveIterator, finish
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Field Detail
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groupSelector
private final GroupSelector<T> groupSelector
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comparators
private final FieldComparator<?>[] comparators
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leafComparators
private final LeafFieldComparator[] leafComparators
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reversed
private final int[] reversed
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topNGroups
private final int topNGroups
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needsScores
private final boolean needsScores
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groupMap
private final java.util.HashMap<T,CollectedSearchGroup<T>> groupMap
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compIDXEnd
private final int compIDXEnd
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orderedGroups
protected java.util.TreeSet<CollectedSearchGroup<T>> orderedGroups
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docBase
private int docBase
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spareSlot
private int spareSlot
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Constructor Detail
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FirstPassGroupingCollector
public FirstPassGroupingCollector(GroupSelector<T> groupSelector, Sort groupSort, int topNGroups)
Create the first pass collector.- Parameters:
groupSelector
- a GroupSelector used to defined groupsgroupSort
- TheSort
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.topNGroups
- How many top groups to keep.
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Method Detail
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scoreMode
public ScoreMode scoreMode()
Description copied from interface:Collector
Indicates what features are required from the scorer.
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getTopGroups
public java.util.Collection<SearchGroup<T>> getTopGroups(int groupOffset) throws java.io.IOException
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.- Parameters:
groupOffset
- The offset in the collected groups- Returns:
- top groups, starting from offset
- Throws:
java.io.IOException
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setScorer
public void setScorer(Scorable scorer) throws java.io.IOException
Description copied from interface:LeafCollector
Called before successive calls toLeafCollector.collect(int)
. Implementations that need the score of the current document (passed-in toLeafCollector.collect(int)
), should save the passed-in Scorer and call scorer.score() when needed.- Specified by:
setScorer
in interfaceLeafCollector
- Overrides:
setScorer
in classSimpleCollector
- Throws:
java.io.IOException
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isCompetitive
private boolean isCompetitive(int doc) throws java.io.IOException
- Throws:
java.io.IOException
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collect
public void collect(int doc) throws java.io.IOException
Description copied from interface:LeafCollector
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
CollectionTerminatedException
. In this case, the last docs of the currentLeafReaderContext
will be skipped andIndexSearcher
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
StoredFields.document(int)
on every hit. Doing so can slow searches by an order of magnitude or more.- Specified by:
collect
in interfaceLeafCollector
- Specified by:
collect
in classSimpleCollector
- Throws:
java.io.IOException
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buildSortedSet
private void buildSortedSet() throws java.io.IOException
- Throws:
java.io.IOException
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doSetNextReader
protected void doSetNextReader(LeafReaderContext readerContext) throws java.io.IOException
Description copied from class:SimpleCollector
This method is called before collectingcontext
.- Overrides:
doSetNextReader
in classSimpleCollector
- Throws:
java.io.IOException
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getGroupSelector
public GroupSelector<T> getGroupSelector()
- Returns:
- the GroupSelector used for this Collector
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