| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.drill.exec.physical.impl.aggregate; |
| |
| import org.apache.drill.exec.compile.TemplateClassDefinition; |
| import org.apache.drill.exec.exception.SchemaChangeException; |
| import org.apache.drill.exec.ops.OperatorContext; |
| import org.apache.drill.exec.record.RecordBatch; |
| import org.apache.drill.exec.record.RecordBatch.IterOutcome; |
| |
| public interface StreamingAggregator { |
| |
| TemplateClassDefinition<StreamingAggregator> TEMPLATE_DEFINITION = |
| new TemplateClassDefinition<StreamingAggregator>(StreamingAggregator.class, StreamingAggTemplate.class); |
| |
| |
| /** |
| * The Aggregator can return one of the following outcomes: |
| * <p> |
| * <b>RETURN_OUTCOME:</b> The aggregation has seen a change in the group and should send data downstream. If |
| * complex writers are involved, then rebuild schema. |
| * <p> |
| * <b>CLEANUP_AND_RETURN:</b> End of all data. Return the data downstream, and cleanup. |
| * <p> |
| * <b>UPDATE_AGGREGATOR:</b> A schema change was encountered. The aggregator's generated code and (possibly) |
| * container need to be updated |
| * <p> |
| * <b>RETURN_AND_RESET:</b> If the aggregator encounters an EMIT, then that implies the end of a data set but |
| * not of all the data. Return the data (aggregated so far) downstream, reset the internal state variables and |
| * come back for the next data set. |
| * <p> |
| * @see org.apache.drill.exec.physical.impl.aggregate.HashAggregator.AggOutcome HashAggregator.AggOutcome |
| */ |
| enum AggOutcome { |
| RETURN_OUTCOME, |
| CLEANUP_AND_RETURN, |
| UPDATE_AGGREGATOR, |
| RETURN_AND_RESET; |
| } |
| |
| void setup(OperatorContext context, RecordBatch incoming, StreamingAggBatch outgoing, int outputRowCount) |
| throws SchemaChangeException; |
| |
| IterOutcome getOutcome(); |
| |
| int getOutputCount(); |
| |
| // do the work. Also pass in the Iteroutcome of the batch already read in case it might be an EMIT. If the |
| // outerOutcome is EMIT, we need to do the work without reading any more batches. |
| AggOutcome doWork(IterOutcome outerOutcome); |
| |
| boolean isDone(); |
| |
| void cleanup(); |
| |
| boolean previousBatchProcessed(); |
| } |