content: /*
   * 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 com.aliyun.odps.lot.operators;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import com.aliyun.odps.lot.common.AggregationFunction;
  import com.aliyun.odps.lot.common.Reference;
  
  import apsara.odps.lot.AggregateProtos;
  import apsara.odps.lot.Lot;
  
  public class Aggregate extends Operator {
  
    private List<Reference> groupByColumns;
    private Map<String, AggregationFunction> functions;
  
    public Aggregate(List<Reference> groupByColumns, Map<String, AggregationFunction> functions) {
      if (groupByColumns == null) {
        this.groupByColumns = new ArrayList<Reference>();
      } else {
        this.groupByColumns = groupByColumns;
      }
  
      if (functions == null) {
        this.functions = new HashMap<String, AggregationFunction>();
      } else {
        this.functions = functions;
      }
    }
  
    public List<Reference> getGroupByColumns() {
      return groupByColumns;
    }
  
    public Map<String, AggregationFunction> getFunctions() {
      return functions;
    }
  
    @Override
    public Lot.LogicalOperator toProtoBuf() {
      assert (getParents().size() == 1);
  
      Lot.LogicalOperator.Builder builder = Lot.LogicalOperator.newBuilder();
  
      AggregateProtos.Aggregate.Builder agg = AggregateProtos.Aggregate.newBuilder();
      agg.setId(getId());
      agg.setParentId(getParents().get(0).getId());
  
      for (Map.Entry<String, AggregationFunction> item : functions.entrySet()) {
        AggregateProtos.Aggregate.Functions.Builder
            func =
            AggregateProtos.Aggregate.Functions.newBuilder();
        func.setAlias(item.getKey());
        func.setFunction(item.getValue().toProtoBuf());
        agg.addFunctions(func);
      }
  
      for (Reference ref : groupByColumns) {
        agg.addGroupByColumns(ref.toProtoBuf().getReference());
      }
  
      builder.setAggregate(agg.build());
      return builder.build();
    }
  }
  