org.apache.flink.runtime.state

Class GenericReducingState<N,T,W extends ValueState<T> & KvState<N>>

java.lang.Object

org.apache.flink.runtime.state.GenericReducingState<N,T,W>

Type Parameters:

N - The type of the namespace.

T - The type of the values stored in this ReducingState.

W - Generic type that extends both the underlying ValueState and KvState.

All Implemented Interfaces:

AppendingState<T,T>, MergingState<T,T>, ReducingState<T>, State, KvState<N>

public class GenericReducingState<N,T,W extends ValueState<T> & KvState<N>>
extends Object
implements ReducingState<T>, KvState<N>

Generic implementation of ReducingState based on a wrapped ValueState.

Constructor Summary

Constructors

Constructor and Description
GenericReducingState(ValueState<T> wrappedState, ReduceFunction<T> reduceFunction) Creates a new ReducingState that wraps the given ValueState.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(T value)
void	clear()
T	get()
byte[]	getSerializedValue(byte[] serializedKeyAndNamespace) Returns the serialized value for the given key and namespace.
void	setCurrentNamespace(N namespace) Sets the current namespace, which will be used when using the state access methods.

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericReducingState

public GenericReducingState(ValueState<T> wrappedState,
                    ReduceFunction<T> reduceFunction)

Creates a new ReducingState that wraps the given ValueState. The ValueState must have a default value of null.

Parameters:

wrappedState - The wrapped ValueState

reduceFunction - The ReduceFunction to use for combining values.

Method Detail

setCurrentNamespace

public void setCurrentNamespace(N namespace)

Description copied from interface: KvState

Sets the current namespace, which will be used when using the state access methods.

Specified by:

setCurrentNamespace in interface KvState<N>

Parameters:

namespace - The namespace.

getSerializedValue

public byte[] getSerializedValue(byte[] serializedKeyAndNamespace)
                          throws Exception

Description copied from interface: KvState

Returns the serialized value for the given key and namespace.

If no value is associated with key and namespace, null is returned.

Specified by:

getSerializedValue in interface KvState<N>

Parameters:

serializedKeyAndNamespace - Serialized key and namespace

Returns:

Serialized value or null if no value is associated with the key and namespace.

Throws:

Exception - Exceptions during serialization are forwarded

get

public T get()
      throws Exception

Specified by:

get in interface AppendingState<T,T>

Throws:

Exception

add

public void add(T value)
         throws Exception

Specified by:

add in interface AppendingState<T,T>

Throws:

Exception

clear

public void clear()

Specified by:

clear in interface State