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 org.apache.calcite.adapter.arrow;
  
  import org.apache.calcite.util.ImmutableIntList;
  import org.apache.calcite.util.Util;
  
  import org.apache.arrow.gandiva.evaluator.Projector;
  import org.apache.arrow.gandiva.exceptions.GandivaException;
  import org.apache.arrow.vector.ipc.ArrowFileReader;
  import org.apache.arrow.vector.ipc.message.ArrowRecordBatch;
  
  import java.io.IOException;
  
  /**
   * Enumerator that reads from a projected collection of Arrow value-vectors.
   */
  class ArrowProjectEnumerator extends AbstractArrowEnumerator {
    private final Projector projector;
  
    ArrowProjectEnumerator(ArrowFileReader arrowFileReader, ImmutableIntList fields,
        Projector projector) {
      super(arrowFileReader, fields);
      this.projector = projector;
    }
  
    @Override protected void evaluateOperator(ArrowRecordBatch arrowRecordBatch) {
      try {
        projector.evaluate(arrowRecordBatch, valueVectors);
      } catch (GandivaException e) {
        throw Util.toUnchecked(e);
      }
    }
  
    @Override public boolean moveNext() {
      if (currRowIndex >= rowCount - 1) {
        final boolean hasNextBatch;
        try {
          hasNextBatch = arrowFileReader.loadNextBatch();
        } catch (IOException e) {
          throw Util.toUnchecked(e);
        }
        if (hasNextBatch) {
          currRowIndex = 0;
          this.valueVectors.clear();
          loadNextArrowBatch();
        }
        return hasNextBatch;
      } else {
        currRowIndex++;
        return true;
      }
    }
  
    @Override public void close() {
      try {
        projector.close();
      } catch (GandivaException e) {
        throw Util.toUnchecked(e);
      }
    }
  }
  