Class AggregateBuilder1<T0>

Type Parameters:
T0 - type of items in stage-0 (the one you obtained this builder from)

public class AggregateBuilder1<T0>
extends Object
Offers a step-by-step API to build a pipeline stage that co-aggregates the data from several input stages. To obtain it, call BatchStage.aggregateBuilder() on the first stage you are co-aggregating and refer to that method's Javadoc for further details.

Note: this is not a builder of AggregateOperation. If that's what you are looking for, go here.

  • Method Details

    • tag0

      @Nonnull public Tag<T0> tag0()
      Returns the tag corresponding to the pipeline stage this builder was obtained from. Use this tag to refer to this stage when building the AggregateOperation that you'll pass to build(aggrOp).
    • add

      @Nonnull public <T> Tag<T> add​(@Nonnull BatchStage<T> stage)
      Adds another stage that will contribute its data to the aggregate operation to be performed. Returns the tag you'll use to refer to this stage when building the AggregateOperation that you'll pass to build().
    • build

      @Nonnull public <R> BatchStage<R> build​(@Nonnull AggregateOperation<?,​R> aggrOp)
      Creates and returns a pipeline stage that performs the co-aggregation of pipeline stages registered with this builder object. The tags you register with the aggregate operation must match the tags you registered with this builder. Refer to the documentation on BatchStage.aggregateBuilder() for more details.
      Type Parameters:
      R - type of the output item
      aggrOp - the aggregate operation to perform
      a new stage representing the co-aggregation