org.apache.flink.runtime.state

接口 StateTransformationFunction<S,T>

类型参数:

S - type of the previous state that is the bases for the computation of the new state.

T - type of the element value that is used to compute the change of state.

@Internal
public interface StateTransformationFunction<S,T>

Interface for a binary function that is used for push-down of state transformation into state backends. The function takes as inputs the old state and an element. From those inputs, the function computes the new state.

方法概要

限定符和类型	方法和说明
S	apply(S previousState, T value) Binary function that applies a given value to the given old state to compute the new state.

方法详细资料

apply

S apply(S previousState,
        T value)
 throws Exception

Binary function that applies a given value to the given old state to compute the new state.

参数:

previousState - the previous state that is the basis for the transformation.

value - the value that the implementation applies to the old state to obtain the new state.

返回:

the new state, computed by applying the given value on the given old state.

抛出:

Exception - if something goes wrong in applying the transformation function.