com.hazelcast.jet.pipeline

## Class WindowAggregateBuilder<R0>

- java.lang.Object
- - com.hazelcast.jet.pipeline.WindowAggregateBuilder<R0>

- Type Parameters:
    `R0` - type of the aggregated result for stream-0

      public class WindowAggregateBuilder<R0>
      extends Object

  Offers a step-by-step fluent API to build a pipeline stage that performs a windowed co-aggregation of the data from several input stages. To obtain it, call `StageWithWindow.aggregateBuilder()` on one of the stages to co-aggregate 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`.

  Since:
    3.0

- - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `<T,R> Tag<R>` | `add(StreamStage<T> stage, AggregateOperation1<? super T,?,? extends R> aggrOp)` Adds another stage that will contribute its data to the aggregate operation to be performed.
    `StreamStage<WindowResult<ItemsByTag>>` | `build()` Creates and returns a pipeline stage that performs a windowed co-aggregation of the stages registered with this builder object.
    `Tag<R0>` | `tag0()` Returns the tag corresponding to the pipeline stage this builder was obtained from.

    - ### Methods inherited from class java.lang.Object

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

- - ### Method Detail

    - #### tag0

          @Nonnull
          public Tag<R0> 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,R> Tag<R> add(StreamStage<T> stage,
                                           AggregateOperation1<? super T,?,? extends R> aggrOp)

      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 StreamStage<WindowResult<ItemsByTag>> build()

      Creates and returns a pipeline stage that performs a windowed co-aggregation of the stages registered with this builder object. The composite aggregate operation places the results of the individual aggregate operations in an `ItemsByTag`.
      Returns:
        a new stage representing the cogroup-and-aggregate operation

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