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

All Implemented Interfaces:: Cacheable

public class ExpressionLambdaAggregatorFactory
extends AggregatorFactory

Nested Class Summary

Nested Classes
Modifier and Type Class Description

class ExpressionLambdaAggregatorFactory.FactorizePlan
Determine how to factorize the aggregator

Field Summary

Fields
Modifier and Type Field Description

static HumanReadableBytes DEFAULT_MAX_SIZE_BYTES

Constructor Summary

Constructors
Constructor	Description
`ExpressionLambdaAggregatorFactory(String name, Set<String> fields, String accumulatorIdentifier, String initialValue, String initialCombineValue, Boolean isNullUnlessAggregated, Boolean shouldAggregateNullInputs, Boolean shouldCombineAggregateNullInputs, String foldExpression, String combineExpression, String compareExpression, String finalizeExpression, HumanReadableBytes maxSizeBytes, ExprMacroTable macroTable)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	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 metricFactory)`
`BufferAggregator`	`factorizeBuffered(ColumnSelectorFactory metricFactory)`
`Object`	`finalizeComputation(Object object)`	"Finalizes" the computation of an object.
`String`	`getAccumulatorIdentifier()`
`byte[]`	`getCacheKey()`	Get a byte array used as a cache key.
`String`	`getCombineExpressionString()`
`AggregatorFactory`	`getCombiningFactory()`	Returns an AggregatorFactory that can be used to combine the output of aggregators from this factory.
`Comparator`	`getComparator()`
`String`	`getCompareExpressionString()`
`Set<String>`	`getFields()`
`String`	`getFinalizeExpressionString()`
`String`	`getFoldExpressionString()`
`String`	`getInitialCombineValueExpressionString()`
`String`	`getInitialValueExpressionString()`
`ColumnType`	`getIntermediateType()`	Get the "intermediate" `ColumnType` for this aggregator.
`boolean`	`getIsNullUnlessAggregated()`
`int`	`getMaxIntermediateSize()`	Returns the maximum size that this aggregator will require in bytes for intermediate storage of results.
`HumanReadableBytes`	`getMaxSizeBytes()`
`String`	`getName()`
`ColumnType`	`getResultType()`	Get the `ColumnType` for the final form of this aggregator, i.e.
`boolean`	`getShouldAggregateNullInputs()`
`boolean`	`getShouldCombineAggregateNullInputs()`
`int`	`hashCode()`
`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, getMergingFactory, getRequiredColumns, getType, guessAggregatorHeapFootprint, makeAggregateCombiner, makeNullableAggregateCombiner, mergeAggregators, optimizeForSegment

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

- Field Detail
  - DEFAULT_MAX_SIZE_BYTES
```
public static final HumanReadableBytes DEFAULT_MAX_SIZE_BYTES
```
- Constructor Detail
  - ExpressionLambdaAggregatorFactory
```
public ExpressionLambdaAggregatorFactory(String name,
                                         @Nullable
                                         Set<String> fields,
                                         @Nullable
                                         String accumulatorIdentifier,
                                         String initialValue,
                                         @Nullable
                                         String initialCombineValue,
                                         @Nullable
                                         Boolean isNullUnlessAggregated,
                                         @Nullable
                                         Boolean shouldAggregateNullInputs,
                                         @Nullable
                                         Boolean shouldCombineAggregateNullInputs,
                                         String foldExpression,
                                         @Nullable
                                         String combineExpression,
                                         @Nullable
                                         String compareExpression,
                                         @Nullable
                                         String finalizeExpression,
                                         @Nullable
                                         HumanReadableBytes maxSizeBytes,
                                         ExprMacroTable macroTable)
```
- Method Detail
  - getName
```
public String getName()
```
    Specified by:
    
    getName in class AggregatorFactory
    
    Returns:
    
    output name of the aggregator column.
  - getFields
```
@Nullable
public Set<String> getFields()
```
  - getAccumulatorIdentifier
```
@Nullable
public String getAccumulatorIdentifier()
```
  - getInitialValueExpressionString
```
public String getInitialValueExpressionString()
```
  - getInitialCombineValueExpressionString
```
public String getInitialCombineValueExpressionString()
```
  - getIsNullUnlessAggregated
```
public boolean getIsNullUnlessAggregated()
```
  - getShouldAggregateNullInputs
```
public boolean getShouldAggregateNullInputs()
```
  - getShouldCombineAggregateNullInputs
```
public boolean getShouldCombineAggregateNullInputs()
```
  - getFoldExpressionString
```
public String getFoldExpressionString()
```
  - getCombineExpressionString
```
public String getCombineExpressionString()
```
  - getCompareExpressionString
```
@Nullable
public String getCompareExpressionString()
```
  - getFinalizeExpressionString
```
@Nullable
public String getFinalizeExpressionString()
```
  - getMaxSizeBytes
```
public HumanReadableBytes getMaxSizeBytes()
```
  - getCacheKey
```
public byte[] getCacheKey()
```
    Description copied from interface: Cacheable
    
    Get a byte array used as a cache key.
    
    Returns:
    
    a cache key
  - factorize
```
public Aggregator factorize(ColumnSelectorFactory metricFactory)
```
    Specified by:
    
    factorize in class AggregatorFactory
  - factorizeBuffered
```
public BufferAggregator factorizeBuffered(ColumnSelectorFactory metricFactory)
```
    Specified by:
    
    factorizeBuffered in class AggregatorFactory
  - getComparator
```
public Comparator getComparator()
```
    Specified by:
    
    getComparator in class AggregatorFactory
  - combine
```
@Nullable
public Object combine(@Nullable
                      Object lhs,
                      @Nullable
                      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
  - 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
```
@Nullable
public 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
  - 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
  - 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.
  - 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.
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class ExpressionLambdaAggregatorFactory

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_MAX_SIZE_BYTES

Constructor Detail

ExpressionLambdaAggregatorFactory

Method Detail

getName

getFields

getAccumulatorIdentifier

getInitialValueExpressionString

getInitialCombineValueExpressionString

getIsNullUnlessAggregated

getShouldAggregateNullInputs

getShouldCombineAggregateNullInputs

getFoldExpressionString

getCombineExpressionString

getCompareExpressionString

getFinalizeExpressionString

getMaxSizeBytes

getCacheKey

factorize

factorizeBuffered

getComparator

combine

deserialize

finalizeComputation

requiredFields

getCombiningFactory

getIntermediateType

getResultType

getMaxIntermediateSize

withName

equals

hashCode

toString