Class StringLastAggregateCombiner
- java.lang.Object
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- org.apache.druid.segment.ObjectColumnSelector<T>
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- org.apache.druid.query.aggregation.ObjectAggregateCombiner<SerializablePairLongString>
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- org.apache.druid.query.aggregation.last.StringLastAggregateCombiner
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- All Implemented Interfaces:
AggregateCombiner<SerializablePairLongString>
,HotLoopCallee
,BaseDoubleColumnValueSelector
,BaseFloatColumnValueSelector
,BaseLongColumnValueSelector
,BaseNullableColumnValueSelector
,BaseObjectColumnValueSelector<SerializablePairLongString>
,ColumnValueSelector<SerializablePairLongString>
public class StringLastAggregateCombiner extends ObjectAggregateCombiner<SerializablePairLongString>
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Field Summary
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Fields inherited from interface org.apache.druid.segment.ColumnValueSelector
EMPTY_ARRAY
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Constructor Summary
Constructors Constructor Description StringLastAggregateCombiner()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Class<SerializablePairLongString>
classOfObject()
Most-specific class of object returned byBaseObjectColumnValueSelector.getObject()
, if known in advance.void
fold(ColumnValueSelector selector)
Folds this AggregateCombiner's state value with the value of the given selector and saves it in this AggregateCombiner's state, e.SerializablePairLongString
getObject()
Returns the currently-selected object.void
reset(ColumnValueSelector selector)
Resets this AggregateCombiner's state value to the value of the given selector, e.-
Methods inherited from class org.apache.druid.segment.ObjectColumnSelector
getDouble, getFloat, getLong, isNull
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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.druid.query.aggregation.AggregateCombiner
inspectRuntimeShape, isNull
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Methods inherited from interface org.apache.druid.segment.BaseDoubleColumnValueSelector
getDouble
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Methods inherited from interface org.apache.druid.segment.BaseFloatColumnValueSelector
getFloat
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Methods inherited from interface org.apache.druid.segment.BaseLongColumnValueSelector
getLong
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Method Detail
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reset
public void reset(ColumnValueSelector selector)
Description copied from interface:AggregateCombiner
Resets this AggregateCombiner's state value to the value of the given selector, e. g. after calling this method combiner.get*() should return the same value as selector.get*(). If the selector is anObjectColumnSelector
, the object returned fromBaseObjectColumnValueSelector.getObject()
must not be modified, and must not become a subject for modification during subsequentAggregateCombiner.fold(org.apache.druid.segment.ColumnValueSelector)
calls.
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fold
public void fold(ColumnValueSelector selector)
Description copied from interface:AggregateCombiner
Folds this AggregateCombiner's state value with the value of the given selector and saves it in this AggregateCombiner's state, e. g. after calling combiner.fold(selector), combiner.get*() should return the value that would be the result ofaggregatorFactory.combine(combiner.get*(), selector.get*())
call. UnlikeAggregatorFactory.combine(java.lang.Object, java.lang.Object)
, if the selector is anObjectColumnSelector
, the object returned fromBaseObjectColumnValueSelector.getObject()
must not be modified, and must not become a subject for modification during subsequent fold() calls. Since the state of AggregateCombiner is undefined beforeAggregateCombiner.reset(org.apache.druid.segment.ColumnValueSelector)
is ever called on it, the effects of calling fold() are also undefined in this case.
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getObject
@Nullable public SerializablePairLongString getObject()
Description copied from interface:BaseObjectColumnValueSelector
Returns the currently-selected object. The behavior of this method depends on the type of selector, which can be determined by callingColumnSelectorFactory.getColumnCapabilities(String)
on the sameColumnSelectorFactory
that you got this selector from. If the capabilties are nonnull, the selector type is given byTypeSignature.getType()
. String selectors, where type isColumnType.STRING
, may return any type of object from this method, especially in cases where the selector is casting objects to string at selection time. Callers are encouraged to avoid the need to deal with various objects by usingColumnSelectorFactory.makeDimensionSelector(org.apache.druid.query.dimension.DimensionSpec)
instead. Numeric selectors, whereTypeSignature.isNumeric()
, may return any type ofNumber
. Callers that wish to deal with more specific types should treat the originalColumnValueSelector
as aBaseLongColumnValueSelector
,BaseDoubleColumnValueSelector
, orBaseFloatColumnValueSelector
instead. Array selectors, whereTypeSignature.isArray()
, must returnObject[]
. The array may contain null elements, and the array itself may also be null. Selectors of unknown type, whereColumnSelectorFactory.getColumnCapabilities(String)
returns null, may return any type of object. Callers must be prepared for a wide variety of possible input objects. This case is common during ingestion, where selectors are built on top of external data.
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classOfObject
public Class<SerializablePairLongString> classOfObject()
Description copied from interface:BaseObjectColumnValueSelector
Most-specific class of object returned byBaseObjectColumnValueSelector.getObject()
, if known in advance. This method returnsObject
when selectors do not know in advance what class of object they may return.
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