core/org.jetbrains.kotlinx.dataframe.impl.aggregation.aggregators

Package-level declarations

Types

class Aggregator<in Value : Any, out Return>(val aggregationHandler: AggregatorAggregationHandler<Value, Return>, val inputHandler: AggregatorInputHandler<Value, Return>, val multipleColumnsHandler: AggregatorMultipleColumnsHandler<Value, Return>, val name: String, val statisticsParameters: Map<String, Any>) : AggregatorInputHandler<Value, Return> , AggregatorMultipleColumnsHandler<Value, Return> , AggregatorAggregationHandler<Value, Return>

This class is the main entry-point for creating an aggregator.

AggregatorAggregationHandler

interface AggregatorAggregationHandler<in Value : Any, out Return> : AggregatorHandler<Value, Return>

The base functionality of the aggregator, which defines how the aggregation of a single Sequence or column is done. It also provides information on which return type will be given, as KType, given a value type. It can also provide the index of the result in the input values if it is a selecting aggregator.

AggregatorHandler

interface AggregatorHandler<in Value : Any, out Return>

Common interface for Aggregator handlers or "injector" objects that can build up an Aggregator instance.

AggregatorInputHandler

interface AggregatorInputHandler<in Value : Any, out Return> : AggregatorHandler<Value, Return>

The input handler of the aggregator, which handles type checks, conversions, and preprocessing of a single sequence of input values. It can also calculate a specific value type from the input values or input types if the (specific) type is not known.

AggregatorMultipleColumnsHandler

interface AggregatorMultipleColumnsHandler<in Value : Any, out Return> : AggregatorHandler<Value, Return>

The multiple columns handler, which specifies how to aggregate multiple columns into a single value by using the supplied AggregatorAggregationHandler. It can also calculate the return type of the aggregation given all input column types.

AggregatorOptionSwitch1

class AggregatorOptionSwitch1<in Param1, in Value : Any, out Return>(val name: String, val getAggregator: (param1: Param1) -> AggregatorProvider<Value, Return>)

Wrapper around an aggregator factory for aggregators that require a single parameter.

AggregatorOptionSwitch2

class AggregatorOptionSwitch2<in Param1, in Param2, in Value : Any, out Return>(val name: String, val getAggregator: (param1: Param1, param2: Param2) -> AggregatorProvider<Value, Return>)

Wrapper around an aggregator factory for aggregators that require two parameters.

AggregatorProvider

fun interface AggregatorProvider<in Value : Any, out Return> : Provider<Aggregator<Value, Return>>

Common interface for providers of Aggregators or "factory" objects that create aggregators.

Aggregators

object Aggregators

CalculateReturnType

internal typealias CalculateReturnType = (type: KType, emptyInput: Boolean) -> KType

Type alias for a function that gives the return type of a Reducer or Selector given some input type and whether the input is empty.

IndexOfResult

internal typealias IndexOfResult<Value> = Sequence<Value?>.(type: KType) -> Int

Type alias for a function that returns the index of the result of Selector in this sequence. If the result is not in the sequence, it returns -1. The type of the values is provided as KType and the sequence can contain nulls.

Provider

fun interface Provider<out T>

Common interface for providers or "factory" objects that create anything of type T.

Reducer

internal typealias Reducer<Value, Return> = Sequence<Value & Any>.(valueType: KType) -> Return

Type alias for a reducer function where the type of the values is provided as KType. Nulls have already been filtered out when this function is called.

Selector

internal typealias Selector<Value, Return> = Sequence<Value & Any>.(type: KType) -> Return

Type alias for a selector function where the type of the values is provided as KType.

ValueType

data class ValueType(val kType: KType, val needsFullConversion: Boolean = false)

Represents the type of values in a column as the input of an aggregator.

Properties

preserveReturnTypeNullIfEmpty

internal val preserveReturnTypeNullIfEmpty: CalculateReturnType

Common case for CalculateReturnType, preserves return type, but makes it nullable for empty inputs.

Functions

aggregate

internal fun <Value : Any, Return> Aggregator<Value, Return>.aggregate(columns: Sequence<DataColumn<Value?>>): Return

Aggregates the data in the given columns and computes a single resulting value.

internal fun <Value : Any, Return> Aggregator<Value, Return>.aggregate(column: DataColumn<Value?>): Return

Aggregates the data in the given column and computes a single resulting value.

@PublishedApi

internal fun <Value : Any, Return> Aggregator<Value, Return>.aggregate(values: Sequence<Value?>, valueType: KType): Return

@PublishedApi

internal fun <Value : Any, Return> Aggregator<Value, Return>.aggregate(values: Sequence<Value?>, valueType: ValueType): Return

Performs aggregation on the given values, taking valueType into account. If valueType is unknown, see calculateValueType or aggregateCalculatingValueType.

aggregateCalculatingValueType

internal fun <Value : Any, Return> Aggregator<Value, Return>.aggregateCalculatingValueType(values: Sequence<Value?>, valueTypes: Set<KType>? = null): Return

If the specific ValueType of the input is not known, but you still want to call aggregate, this function can be called to calculate it by combining the set of known valueTypes or by gathering the types from values and then aggregating them.

calculateValueType

internal fun <Value : Any, Return> Aggregator<Value, Return>.calculateValueType(values: Sequence<Value?>, valueTypes: Set<KType>? = null): ValueType

cast

@PublishedApi

internal fun <Type> Aggregator<*, *>.cast(): Aggregator<Type & Any, Type>

cast2

@PublishedApi

internal fun <Value : Any, Return> Aggregator<*, *>.cast2(): Aggregator<Value, Return>

getValue

internal operator fun <T> Provider<T>.getValue(obj: Any?, property: KProperty<*>): T

indexOfAggregationResult

@PublishedApi

internal fun <Value : Return & Any, Return> Aggregator<Value, Return>.indexOfAggregationResult(values: Sequence<Value?>, valueType: KType): Int

@PublishedApi

internal fun <Value : Return & Any, Return> Aggregator<Value, Return>.indexOfAggregationResult(values: Sequence<Value?>, valueType: ValueType): Int

Gives the index of the aggregation result in the input values, if it applies. This is used for aggregators with an AggregatorAggregationHandler where Value== Return, and where the result exists in the input.

toValueType

internal fun KType.toValueType(needsFullConversion: Boolean = false): ValueType