Package com.hazelcast.jet.aggregate

Interface AggregateOperation1<T,​A,​R>

  • Type Parameters:
    T - the type of the stream item
    A - the type of the accumulator
    R - the type of the aggregation result
    All Superinterfaces:
    AggregateOperation<A,​R>, java.io.Serializable
    public interface AggregateOperation1<T,​A,​R>
extends AggregateOperation<A,​R>
    Specialization of AggregateOperation (refer to its extensive documentation) to the "arity-1" case with a single data stream being aggregated over. AggregateOperations contains factories for the built-in implementations and you can create your own using the aggregate operation builder.

    All the functions must be stateless and cooperative.

    Since:
    Jet 3.0

    • Method Detail

      • accumulateFn

        @Nonnull
BiConsumerEx<? super A,​? super T> accumulateFn()
        A primitive that updates the accumulator state to account for a new item.

        The consumer must be stateless and cooperative.

      • withAccumulateFn

        @Nonnull
<NEW_T> AggregateOperation1<NEW_T,​A,​R> withAccumulateFn​(BiConsumerEx<? super A,​? super NEW_T> accumulateFn)
        Returns a copy of this aggregate operation, but with the accumulate primitive replaced with the one supplied here.

        The consumer must be stateless and cooperative.

      • withIdentityFinish

        @Nonnull
AggregateOperation1<T,​A,​A> withIdentityFinish()
        Description copied from interface: AggregateOperation
        Returns a copy of this aggregate operation, but with the finish primitive replaced with the identity function. It will return the accumulator object as-is. The returned aggregate operation does not support the export primitive.
        Specified by:
        withIdentityFinish in interface AggregateOperation<T,​A>

      • andThen

        @Nonnull
<R_NEW> AggregateOperation1<T,​A,​R_NEW> andThen​(FunctionEx<? super R,​? extends R_NEW> thenFn)
        Description copied from interface: AggregateOperation
        Returns a copy of this aggregate operation, but with the export and finish primitives composed with the supplied thenFn. This replaces exportFn with exportFn.andThen(thenFn), same for finishFn. The main use case is to transform the result of an existing (library-provided) aggregate operation.

        The given function must be stateless and cooperative.

        Specified by:
        andThen in interface AggregateOperation<T,​A>
        Type Parameters:
        R_NEW - the type of the returned aggregate operation's result
        Parameters:
        thenFn - the function to apply to the results of export and finish primitives