Package org.apache.calcite.schema.impl

Class AggregateFunctionImpl

java.lang.Object

org.apache.calcite.schema.impl.AggregateFunctionImpl

All Implemented Interfaces:

AggregateFunction, Function, ImplementableAggFunction

public class AggregateFunctionImpl
extends Object
implements AggregateFunction, ImplementableAggFunction

Implementation of AggregateFunction via user-defined class. The class should implement A init(), A add(A, V), and R result(A) methods. All the methods should be either static or instance. Bonus point: when using non-static implementation, the aggregate object is reused through the calculation, thus it can have aggregation-related state.

Field Summary

Fields

Modifier and Type	Field	Description
final Class<?>	accumulatorType
final Method	addMethod
final Class<?>	declaringClass
final Method	initMethod
final boolean	isStatic
final @Nullable Method	mergeMethod
final @Nullable Method	resultMethod
final Class<?>	resultType
final com.google.common.collect.ImmutableList<Class<?>>	valueTypes

Method Summary

Modifier and Type	Method	Description
static @Nullable AggregateFunctionImpl	create(Class<?> clazz)	Creates an aggregate function, or returns null.
AggImplementor	getImplementor(boolean windowContext)	Returns implementor that translates the function to linq4j expression.
List<FunctionParameter>	getParameters()	Returns the parameters of this function.
RelDataType	getReturnType(RelDataTypeFactory typeFactory)	Returns the return type of this function, constructed using the given type factory.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

isStatic

public final boolean isStatic

initMethod

public final Method initMethod

addMethod

public final Method addMethod

mergeMethod

public final @Nullable Method mergeMethod

resultMethod

public final @Nullable Method resultMethod

valueTypes

public final com.google.common.collect.ImmutableList<Class<?>> valueTypes

accumulatorType

public final Class<?> accumulatorType

resultType

public final Class<?> resultType

declaringClass

public final Class<?> declaringClass

Method Details

create

public static @Nullable AggregateFunctionImpl create(Class<?> clazz)

Creates an aggregate function, or returns null.

getParameters

public List<FunctionParameter> getParameters()

Description copied from interface: Function

Returns the parameters of this function.

Specified by:

getParameters in interface Function

Returns:

Parameters; never null

getReturnType

public RelDataType getReturnType(RelDataTypeFactory typeFactory)

Description copied from interface: AggregateFunction

Returns the return type of this function, constructed using the given type factory.

Specified by:

getReturnType in interface AggregateFunction

Parameters:

typeFactory - Type factory

getImplementor

public AggImplementor getImplementor(boolean windowContext)

Description copied from interface: ImplementableAggFunction

Returns implementor that translates the function to linq4j expression.

Specified by:

getImplementor in interface ImplementableAggFunction

Parameters:

windowContext - true when aggregate is used in window context

Returns:

implementor that translates the function to linq4j expression.