com.hazelcast.jet.pipeline.GroupAggregateBuilder Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2024, 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.Util;
import com.hazelcast.jet.aggregate.AggregateOperation;
import com.hazelcast.jet.aggregate.AggregateOperation1;
import com.hazelcast.jet.aggregate.CoAggregateOperationBuilder;
import com.hazelcast.jet.datamodel.ItemsByTag;
import com.hazelcast.jet.datamodel.Tag;
import com.hazelcast.jet.impl.pipeline.GrAggBuilder;
import javax.annotation.Nonnull;
import java.util.Map.Entry;
import static com.hazelcast.jet.aggregate.AggregateOperations.coAggregateOperationBuilder;
/**
* Offers a step-by-step API to build a pipeline stage that co-groups and
* aggregates the data from several input stages. To obtain it, call {@link
* BatchStageWithKey#aggregateBuilder(AggregateOperation1)
* stage.aggregateBuilder(aggrOp)} on one of the stages to co-group 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 the grouping key
* @param type of the aggregation result for stream-0
*
* @since Jet 3.0
*/
public class GroupAggregateBuilder {
private final GrAggBuilder grAggBuilder;
private final CoAggregateOperationBuilder aggrOpBuilder = coAggregateOperationBuilder();
GroupAggregateBuilder(
@Nonnull BatchStageWithKey stage0,
@Nonnull AggregateOperation1 aggrOp0
) {
grAggBuilder = new GrAggBuilder<>(stage0);
aggrOpBuilder.add(Tag.tag0(), aggrOp0);
}
/**
* 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 BatchStageWithKey stage,
@Nonnull AggregateOperation1 aggrOp
) {
Tag tag = grAggBuilder.add(stage);
return aggrOpBuilder.add(tag, aggrOp);
}
/**
* Creates and returns a pipeline stage that performs the co-aggregation
* of the stages registered with this builder object and emits a {@code
* Map.Entry(key, resultsByTag)} for each distinct key. The composite
* aggregate operation places the results of the individual aggregate
* operations in an {@code ItemsByTag}. Use the tags you got from this
* builder to access the results.
*
* @return a new stage representing the co-aggregation
*/
@Nonnull
public BatchStage> build() {
AggregateOperation aggrOp = aggrOpBuilder.build();
return grAggBuilder.buildBatch(aggrOp, Util::entry);
}
}