com.hazelcast.jet.pipeline.AggregateBuilder1 Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2021, Hazelcast, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.jet.pipeline;
import com.hazelcast.jet.aggregate.AggregateOperation;
import com.hazelcast.jet.datamodel.Tag;
import com.hazelcast.jet.impl.pipeline.AggBuilder;
import com.hazelcast.jet.impl.pipeline.AggBuilder.CreateOutStageFn;
import com.hazelcast.jet.impl.pipeline.BatchStageImpl;
import javax.annotation.Nonnull;
/**
* Offers a step-by-step API to build a pipeline stage that co-aggregates
* the data from several input stages. To obtain it, call {@link
* 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 {@code
* AggregateOperation}. If that's what you are looking for, go {@link
* AggregateOperation#withCreate here}.
*
* @param type of items in stage-0 (the one you obtained this builder from)
*
* @since Jet 3.0
*/
public class AggregateBuilder1 {
private final AggBuilder aggBuilder;
AggregateBuilder1(@Nonnull BatchStage stage) {
this.aggBuilder = new AggBuilder(stage, null);
}
/**
* Returns the tag corresponding to the pipeline stage this builder
* was obtained from. Use this tag to refer to this stage when building
* the {@code AggregateOperation} that you'll pass to {@link #build
* build(aggrOp)}.
*/
@Nonnull
public Tag tag0() {
return Tag.tag0();
}
/**
* 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 {@code AggregateOperation} that you'll pass to
* {@link #build build()}.
*/
@Nonnull
public Tag add(@Nonnull BatchStage stage) {
return aggBuilder.add(stage);
}
/**
* 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 {@link
* BatchStage#aggregateBuilder()} for more details.
*
* @param aggrOp the aggregate operation to perform
* @param type of the output item
* @return a new stage representing the co-aggregation
*/
@Nonnull
public BatchStage build(@Nonnull AggregateOperation aggrOp) {
CreateOutStageFn> createOutStageFn = BatchStageImpl::new;
return aggBuilder.build(aggrOp, createOutStageFn);
}
}