JavaScriptAggregatorFactory (druid-processing 25.0.0 API)

java.lang.Object
- org.apache.druid.query.aggregation.AggregatorFactory
- - org.apache.druid.query.aggregation.JavaScriptAggregatorFactory

All Implemented Interfaces:: Cacheable

public class JavaScriptAggregatorFactory
extends AggregatorFactory

Constructor Summary

Constructors
Constructor and Description
`JavaScriptAggregatorFactory(String name, List<String> fieldNames, String fnAggregate, String fnReset, String fnCombine, JavaScriptConfig config)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Object`	`combine(Object lhs, Object rhs)` A method that knows how to combine the outputs of `Aggregator.get()` produced via `AggregatorFactory.factorize(org.apache.druid.segment.ColumnSelectorFactory)` or `BufferAggregator.get(java.nio.ByteBuffer, int)` produced via `AggregatorFactory.factorizeBuffered(org.apache.druid.segment.ColumnSelectorFactory)`.
`Object`	`deserialize(Object object)` A method that knows how to "deserialize" the object from whatever form it might have been put into in order to transfer via JSON.
`boolean`	`equals(Object o)`
`Aggregator`	`factorize(ColumnSelectorFactory columnFactory)`
`BufferAggregator`	`factorizeBuffered(ColumnSelectorFactory columnSelectorFactory)`
`@Nullable Object`	`finalizeComputation(@Nullable Object object)` "Finalizes" the computation of an object.
`byte[]`	`getCacheKey()`
`AggregatorFactory`	`getCombiningFactory()` Returns an AggregatorFactory that can be used to combine the output of aggregators from this factory.
`Comparator`	`getComparator()`
`List<String>`	`getFieldNames()`
`String`	`getFnAggregate()`
`String`	`getFnCombine()`
`String`	`getFnReset()`
`ColumnType`	`getIntermediateType()` Get the "intermediate" `ColumnType` for this aggregator.
`int`	`getMaxIntermediateSize()` Returns the maximum size that this aggregator will require in bytes for intermediate storage of results.
`AggregatorFactory`	`getMergingFactory(AggregatorFactory other)` Returns an AggregatorFactory that can be used to combine the output of aggregators from this factory and another factory.
`String`	`getName()`
`List<AggregatorFactory>`	`getRequiredColumns()` Used by `GroupByStrategyV1` when running nested groupBys, to "transfer" values from this aggreagtor to an incremental index that the outer query will run on.
`ColumnType`	`getResultType()` Get the `ColumnType` for the final form of this aggregator, i.e.
`int`	`hashCode()`
`AggregateCombiner`	`makeAggregateCombiner()` Creates an AggregateCombiner to fold rollup aggregation results from serveral "rows" of different indexes during index merging.
`List<String>`	`requiredFields()` Get a list of fields that aggregators built by this factory will need to read.
`String`	`toString()`
`AggregatorFactory`	`withName(String newName)` Used in cases where we want to change the output name of the aggregator to something else.

Methods inherited from class org.apache.druid.query.aggregation.AggregatorFactory
canVectorize, factorizeVector, factorizeWithSize, getComplexTypeName, getFinalizedType, getMaxIntermediateSizeWithNulls, getType, guessAggregatorHeapFootprint, makeNullableAggregateCombiner, mergeAggregators, optimizeForSegment

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

- Constructor Detail
  - JavaScriptAggregatorFactory
```
public JavaScriptAggregatorFactory(String name,
                                   List<String> fieldNames,
                                   String fnAggregate,
                                   String fnReset,
                                   String fnCombine,
                                   JavaScriptConfig config)
```
- Method Detail
  - factorize
```
public Aggregator factorize(ColumnSelectorFactory columnFactory)
```
    Specified by:
    
    factorize in class AggregatorFactory
  - factorizeBuffered
```
public BufferAggregator factorizeBuffered(ColumnSelectorFactory columnSelectorFactory)
```
    Specified by:
    
    factorizeBuffered in class AggregatorFactory
  - getComparator
```
public Comparator getComparator()
```
    Specified by:
    
    getComparator in class AggregatorFactory
  - combine
```
public Object combine(Object lhs,
                      Object rhs)
```
    Description copied from class: AggregatorFactory
    
    A method that knows how to combine the outputs of Aggregator.get() produced via AggregatorFactory.factorize(org.apache.druid.segment.ColumnSelectorFactory) or BufferAggregator.get(java.nio.ByteBuffer, int) produced via AggregatorFactory.factorizeBuffered(org.apache.druid.segment.ColumnSelectorFactory). Note, even though this method is called "combine", this method's contract *does* allow for mutation of the input objects. Thus, any use of lhs or rhs after calling this method is highly discouraged.
    
    Specified by:
    
    combine in class AggregatorFactory
    
    Parameters:
    
    lhs - The left hand side of the combine
    
    rhs - The right hand side of the combine
    
    Returns:
    
    an object representing the combination of lhs and rhs, this can be a new object or a mutation of the inputs
  - makeAggregateCombiner
```
public AggregateCombiner makeAggregateCombiner()
```
    Description copied from class: AggregatorFactory
    
    Creates an AggregateCombiner to fold rollup aggregation results from serveral "rows" of different indexes during index merging. AggregateCombiner implements the same logic as AggregatorFactory.combine(java.lang.Object, java.lang.Object), with the difference that it uses ColumnValueSelector and it's subinterfaces to get inputs and implements ColumnValueSelector to provide output.
    
    Overrides:
    
    makeAggregateCombiner in class AggregatorFactory
    
    See Also:
    
    AggregateCombiner, IndexMerger
  - getCombiningFactory
```
public AggregatorFactory getCombiningFactory()
```
    Description copied from class: AggregatorFactory
    
    Returns an AggregatorFactory that can be used to combine the output of aggregators from this factory. It is used when we know we have some values that were produced with this aggregator factory, and want to do some additional combining of them. This happens, for example, when merging query results from two different segments, or two different servers. For simple aggregators, the combining factory may be computed by simply creating a new factory that is the same as the current, except with its input column renamed to the same as the output column. For example, this aggregator: {"type": "longSum", "fieldName": "foo", "name": "bar"} Would become: {"type": "longSum", "fieldName": "bar", "name": "bar"} Sometimes, the type or other parameters of the combining aggregator will be different from the original aggregator. For example, the CountAggregatorFactory getCombiningFactory method will return a LongSumAggregatorFactory, because counts are combined by summing. No matter what, `foo.getCombiningFactory()` and `foo.getCombiningFactory().getCombiningFactory()` should return the same result.
    
    Specified by:
    
    getCombiningFactory in class AggregatorFactory
    
    Returns:
    
    a new Factory that can be used for operations on top of data output from the current factory.
  - getMergingFactory
```
public AggregatorFactory getMergingFactory(AggregatorFactory other)
                                    throws AggregatorFactoryNotMergeableException
```
    Description copied from class: AggregatorFactory
    
    Returns an AggregatorFactory that can be used to combine the output of aggregators from this factory and another factory. It is used when we have some values produced by this aggregator factory, and some values produced by the "other" aggregator factory, and we want to do some additional combining of them. This happens, for example, when compacting two segments together that both have a metric column with the same name. (Even though the name of the column is the same, the aggregator factory used to create it may be different from segment to segment.) This method may throw AggregatorFactoryNotMergeableException, meaning that "this" and "other" are not compatible and values from one cannot sensibly be combined with values from the other.
    
    Overrides:
    
    getMergingFactory in class AggregatorFactory
    
    Returns:
    
    a new Factory that can be used for merging the output of aggregators from this factory and other.
    
    Throws:
    
    AggregatorFactoryNotMergeableException
    
    See Also:
    
    which is equivalent to {@code foo.getMergingFactory(foo)} (when "this" and "other" are the same instance).
  - getRequiredColumns
```
public List<AggregatorFactory> getRequiredColumns()
```
    Description copied from class: AggregatorFactory
    
    Used by GroupByStrategyV1 when running nested groupBys, to "transfer" values from this aggreagtor to an incremental index that the outer query will run on. This method only exists due to the design of GroupByStrategyV1, and should probably not be used for anything else. If you are here because you are looking for a way to get the input fields required by this aggregator, and thought "getRequiredColumns" sounded right, please use AggregatorFactory.requiredFields() instead.
    
    Specified by:
    
    getRequiredColumns in class AggregatorFactory
    
    Returns:
    
    AggregatorFactories that can be used to "transfer" values from this aggregator into an incremental index
    
    See Also:
    
    a similarly-named method that is perhaps the one you want instead.
  - deserialize
```
public Object deserialize(Object object)
```
    Description copied from class: AggregatorFactory
    
    A method that knows how to "deserialize" the object from whatever form it might have been put into in order to transfer via JSON.
    
    Specified by:
    
    deserialize in class AggregatorFactory
    
    Parameters:
    
    object - the object to deserialize
    
    Returns:
    
    the deserialized object
  - finalizeComputation
```
public @Nullable Object finalizeComputation(@Nullable Object object)
```
    Description copied from class: AggregatorFactory
    
    "Finalizes" the computation of an object. Primarily useful for complex types that have a different mergeable intermediate format than their final resultant output.
    
    Specified by:
    
    finalizeComputation in class AggregatorFactory
    
    Parameters:
    
    object - the object to be finalized
    
    Returns:
    
    the finalized value that should be returned for the initial query
  - getName
```
public String getName()
```
    Specified by:
    
    getName in class AggregatorFactory
    
    Returns:
    
    output name of the aggregator column.
  - getFieldNames
```
public List<String> getFieldNames()
```
  - getFnAggregate
```
public String getFnAggregate()
```
  - getFnReset
```
public String getFnReset()
```
  - getFnCombine
```
public String getFnCombine()
```
  - requiredFields
```
public List<String> requiredFields()
```
    Description copied from class: AggregatorFactory
    
    Get a list of fields that aggregators built by this factory will need to read.
    
    Specified by:
    
    requiredFields in class AggregatorFactory
  - getCacheKey
```
public byte[] getCacheKey()
```
  - getIntermediateType
```
public ColumnType getIntermediateType()
```
    Description copied from class: AggregatorFactory
    
    Get the "intermediate" ColumnType for this aggregator. This is the same as the type returned by AggregatorFactory.deserialize(java.lang.Object) and the type accepted by AggregatorFactory.combine(java.lang.Object, java.lang.Object). However, it is *not* necessarily the same type returned by AggregatorFactory.finalizeComputation(java.lang.Object). Refer to the ColumnType javadocs for details on the implications of choosing a type.
    
    Overrides:
    
    getIntermediateType in class AggregatorFactory
  - getResultType
```
public ColumnType getResultType()
```
    Description copied from class: AggregatorFactory
    
    Get the ColumnType for the final form of this aggregator, i.e. the type of the value returned by AggregatorFactory.finalizeComputation(java.lang.Object). This may be the same as or different than the types expected in AggregatorFactory.deserialize(java.lang.Object) and AggregatorFactory.combine(java.lang.Object, java.lang.Object). Refer to the ColumnType javadocs for details on the implications of choosing a type.
    
    Overrides:
    
    getResultType in class AggregatorFactory
  - getMaxIntermediateSize
```
public int getMaxIntermediateSize()
```
    Description copied from class: AggregatorFactory
    
    Returns the maximum size that this aggregator will require in bytes for intermediate storage of results.
    
    Specified by:
    
    getMaxIntermediateSize in class AggregatorFactory
    
    Returns:
    
    the maximum number of bytes that an aggregator of this type will require for intermediate result storage.
  - withName
```
public AggregatorFactory withName(String newName)
```
    Description copied from class: AggregatorFactory
    
    Used in cases where we want to change the output name of the aggregator to something else. For eg: if we have a query `select a, sum(b) as total group by a from table` the aggregator returned from the native group by query is "a0" set in org.apache.druid.sql.calcite.rel.DruidQuery#computeAggregations. We can use withName("total") to set the output name of the aggregator to "total".
    As all implementations of this interface method may not exist, callers of this method are advised to handle such a case.
    
    Overrides:
    
    withName in class AggregatorFactory
    
    Parameters:
    
    newName - newName of the output for aggregator factory
    
    Returns:
    
    AggregatorFactory with the output name set as the input param.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object

Class JavaScriptAggregatorFactory

Constructor Summary

Method Summary

Methods inherited from class org.apache.druid.query.aggregation.AggregatorFactory

Methods inherited from class java.lang.Object

Constructor Detail

JavaScriptAggregatorFactory

Method Detail

factorize

factorizeBuffered

getComparator

combine

makeAggregateCombiner

getCombiningFactory

getMergingFactory

getRequiredColumns

deserialize

finalizeComputation

getName

getFieldNames

getFnAggregate

getFnReset

getFnCombine

requiredFields

getCacheKey

getIntermediateType

getResultType

getMaxIntermediateSize

withName

toString

equals

hashCode