Class GroupSelector<T>
- java.lang.Object
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- org.apache.lucene.search.grouping.GroupSelector<T>
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- Type Parameters:
T
- the type of the group value
- Direct Known Subclasses:
TermGroupSelector
,ValueSourceGroupSelector
public abstract class GroupSelector<T> extends Object
Defines a group, for use by grouping collectors A GroupSelector acts as an iterator over documents. For each segment, clients should callsetNextReader(LeafReaderContext)
, and thenadvanceTo(int)
for each matching document.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
GroupSelector.State
What to do with the current value
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Constructor Summary
Constructors Constructor Description GroupSelector()
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description abstract GroupSelector.State
advanceTo(int doc)
Advance the GroupSelector's iterator to the given documentabstract T
copyValue()
abstract T
currentValue()
Get the group value of the current document N.B.abstract void
setGroups(Collection<SearchGroup<T>> groups)
Set a restriction on the group values returned by this selector If the selector is positioned on a document whose group value is not contained within this set, thenadvanceTo(int)
will returnGroupSelector.State.SKIP
abstract void
setNextReader(LeafReaderContext readerContext)
Set the LeafReaderContext
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Method Detail
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setNextReader
public abstract void setNextReader(LeafReaderContext readerContext) throws IOException
Set the LeafReaderContext- Throws:
IOException
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advanceTo
public abstract GroupSelector.State advanceTo(int doc) throws IOException
Advance the GroupSelector's iterator to the given document- Throws:
IOException
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currentValue
public abstract T currentValue()
Get the group value of the current document N.B. this object may be reused, for a persistent version usecopyValue()
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copyValue
public abstract T copyValue()
- Returns:
- a copy of the group value of the current document
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setGroups
public abstract void setGroups(Collection<SearchGroup<T>> groups)
Set a restriction on the group values returned by this selector If the selector is positioned on a document whose group value is not contained within this set, thenadvanceTo(int)
will returnGroupSelector.State.SKIP
- Parameters:
groups
- a set ofSearchGroup
objects to limit selections to
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