org.apache.flink.api.common.state

Class ReducingStateDescriptor<T>

java.lang.Object

org.apache.flink.api.common.state.StateDescriptor<ReducingState<T>,T>

org.apache.flink.api.common.state.ReducingStateDescriptor<T>

Type Parameters:

T - The type of the values that can be added to the list state.

All Implemented Interfaces:

Serializable

@PublicEvolving
public class ReducingStateDescriptor<T>
extends StateDescriptor<ReducingState<T>,T>

StateDescriptor for ReducingState. This can be used to create partitioned reducing state using RuntimeContext.getReducingState(ReducingStateDescriptor).

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.flink.api.common.state.StateDescriptor

defaultValue, name, serializer

Constructor Summary

Constructors

Constructor and Description
ReducingStateDescriptor(String name, ReduceFunction<T> reduceFunction, Class<T> typeClass) Creates a new ReducingStateDescriptor with the given name, type, and default value.
ReducingStateDescriptor(String name, ReduceFunction<T> reduceFunction, TypeInformation<T> typeInfo) Creates a new ReducingStateDescriptor with the given name and default value.
ReducingStateDescriptor(String name, ReduceFunction<T> reduceFunction, TypeSerializer<T> typeSerializer) Creates a new ValueStateDescriptor with the given name and default value.

Method Summary

Modifier and Type	Method and Description
ReducingState<T>	bind(StateBackend stateBackend) Creates a new State on the given StateBackend.
boolean	equals(Object o)
ReduceFunction<T>	getReduceFunction() Returns the reduce function to be used for the reducing state.
int	hashCode()
String	toString()

Methods inherited from class org.apache.flink.api.common.state.StateDescriptor

getDefaultValue, getName, getSerializer, initializeSerializerUnlessSet, isSerializerInitialized

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ReducingStateDescriptor

public ReducingStateDescriptor(String name,
                               ReduceFunction<T> reduceFunction,
                               Class<T> typeClass)

Creates a new ReducingStateDescriptor with the given name, type, and default value.

If this constructor fails (because it is not possible to describe the type via a class), consider using the ReducingStateDescriptor(String, ReduceFunction, TypeInformation) constructor.

Parameters:

name - The (unique) name for the state.

reduceFunction - The ReduceFunction used to aggregate the state.

typeClass - The type of the values in the state.

ReducingStateDescriptor

public ReducingStateDescriptor(String name,
                               ReduceFunction<T> reduceFunction,
                               TypeInformation<T> typeInfo)

Creates a new ReducingStateDescriptor with the given name and default value.

Parameters:

name - The (unique) name for the state.

reduceFunction - The ReduceFunction used to aggregate the state.

typeInfo - The type of the values in the state.

ReducingStateDescriptor

public ReducingStateDescriptor(String name,
                               ReduceFunction<T> reduceFunction,
                               TypeSerializer<T> typeSerializer)

Creates a new ValueStateDescriptor with the given name and default value.

Parameters:

name - The (unique) name for the state.

reduceFunction - The ReduceFunction used to aggregate the state.

typeSerializer - The type serializer of the values in the state.

Method Detail

bind

public ReducingState<T> bind(StateBackend stateBackend)
                      throws Exception

Description copied from class: StateDescriptor

Creates a new State on the given StateBackend.

Specified by:

bind in class StateDescriptor<ReducingState<T>,T>

Parameters:

stateBackend - The StateBackend on which to create the State.

Throws:

Exception

getReduceFunction

public ReduceFunction<T> getReduceFunction()

Returns the reduce function to be used for the reducing state.

equals

public boolean equals(Object o)

Specified by:

equals in class StateDescriptor<ReducingState<T>,T>

hashCode

public int hashCode()

Specified by:

hashCode in class StateDescriptor<ReducingState<T>,T>

toString

public String toString()

Overrides:

toString in class StateDescriptor<ReducingState<T>,T>