org.apache.flink.api.common.state

Interface StateBinder

@Internal
public interface StateBinder

The StateBinder is used by StateDescriptor instances to create actual State objects.

Method Summary

Modifier and Type	Method and Description
<IN,ACC,OUT> AggregatingState<IN,OUT>	createAggregatingState(AggregatingStateDescriptor<IN,ACC,OUT> stateDesc) Creates and returns a new AggregatingState.
<T,ACC> FoldingState<T,ACC>	createFoldingState(FoldingStateDescriptor<T,ACC> stateDesc) Deprecated. will be removed in a future version in favor of AggregatingState
<T> ListState<T>	createListState(ListStateDescriptor<T> stateDesc) Creates and returns a new ListState.
<MK,MV> MapState<MK,MV>	createMapState(MapStateDescriptor<MK,MV> stateDesc) Creates and returns a new MapState.
<T> ReducingState<T>	createReducingState(ReducingStateDescriptor<T> stateDesc) Creates and returns a new ReducingState.
<T> ValueState<T>	createValueState(ValueStateDescriptor<T> stateDesc) Creates and returns a new ValueState.

Method Detail

createValueState

<T> ValueState<T> createValueState(ValueStateDescriptor<T> stateDesc)
                            throws Exception

Creates and returns a new ValueState.

Type Parameters:

T - The type of the value that the ValueState can store.

Parameters:

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception

createListState

<T> ListState<T> createListState(ListStateDescriptor<T> stateDesc)
                          throws Exception

Creates and returns a new ListState.

Type Parameters:

T - The type of the values that the ListState can store.

Parameters:

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception

createReducingState

<T> ReducingState<T> createReducingState(ReducingStateDescriptor<T> stateDesc)
                                  throws Exception

Creates and returns a new ReducingState.

Type Parameters:

T - The type of the values that the ReducingState can store.

Parameters:

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception

createAggregatingState

<IN,ACC,OUT> AggregatingState<IN,OUT> createAggregatingState(AggregatingStateDescriptor<IN,ACC,OUT> stateDesc)
                                                      throws Exception

Creates and returns a new AggregatingState.

Type Parameters:

IN - The type of the values that go into the aggregating state

ACC - The type of the values that are stored in the aggregating state

OUT - The type of the values that come out of the aggregating state

Parameters:

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception

createFoldingState

@Deprecated
<T,ACC> FoldingState<T,ACC> createFoldingState(FoldingStateDescriptor<T,ACC> stateDesc)
                                                    throws Exception

Deprecated. will be removed in a future version in favor of AggregatingState

Creates and returns a new FoldingState.

Type Parameters:

T - Type of the values folded into the state

ACC - Type of the value in the state

Parameters:

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception

createMapState

<MK,MV> MapState<MK,MV> createMapState(MapStateDescriptor<MK,MV> stateDesc)
                                throws Exception

Creates and returns a new MapState.

Type Parameters:

MK - Type of the keys in the state

MV - Type of the values in the state

Parameters:

stateDesc - The StateDescriptor that contains the name of the state.

Throws:

Exception