OutputColumnAstNode.java example

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/**
 * Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com)
 *
 * 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.linkedin.pinot.pql.parsers.pql2.ast;

import com.linkedin.pinot.common.request.BrokerRequest;
import com.linkedin.pinot.common.request.Selection;
import com.linkedin.pinot.pql.parsers.Pql2CompilationException;


/**
 * AST node for an output column.
 */
public class OutputColumnAstNode extends BaseAstNode {
  @Override
  public void updateBrokerRequest(BrokerRequest brokerRequest) {
    for (AstNode astNode : getChildren()) {
      // If the column is a function call, it must be an aggregation function
      if (astNode instanceof FunctionCallAstNode) {
        FunctionCallAstNode node = (FunctionCallAstNode) astNode;
        brokerRequest.addToAggregationsInfo(node.buildAggregationInfo());
      } else if (astNode instanceof IdentifierAstNode) {
        Selection selection = brokerRequest.getSelections();
        if (selection == null) {
          selection = new Selection();
          brokerRequest.setSelections(selection);
        }

        IdentifierAstNode node = (IdentifierAstNode) astNode;
        selection.addToSelectionColumns(node.getName());
      } else {
        throw new Pql2CompilationException("Output column is neither a function nor an identifier");
      }
    }
  }
}