content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.job.plan.transform.format.orc;
  
  import alluxio.AlluxioURI;
  import alluxio.job.plan.transform.format.JobPath;
  import alluxio.job.plan.transform.format.ReadWriterUtils;
  import alluxio.job.plan.transform.format.TableReader;
  import alluxio.job.plan.transform.format.TableRow;
  import alluxio.job.plan.transform.format.TableSchema;
  
  import com.google.common.io.Closer;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hive.ql.exec.vector.VectorizedRowBatch;
  import org.apache.orc.OrcFile;
  import org.apache.orc.Reader;
  import org.apache.orc.RecordReader;
  
  import java.io.IOException;
  import java.util.List;
  
  /**
   * The Orc reader.
   */
  public final class OrcReader implements TableReader {
  
    private final Closer mCloser;
    private final OrcSchema mSchema;
    private final Reader mReader;
    private final RecordReader mRows;
    private final List<String> mFieldNames;
  
    /**
     * The current processing batch of the Orc reader for the read() operation.
     */
    private VectorizedRowBatch mCurrentBatch;
    /**
     * The row position inside the vectorized row batch to return next for read().
     */
    private int mCurrentBatchPosition;
  
    private OrcReader(JobPath inputPath) throws IOException {
      mCloser = Closer.create();
      try {
  
        Configuration conf = ReadWriterUtils.readNoCacheConf();
  
        mReader = mCloser.register(OrcFile.createReader(inputPath, OrcFile.readerOptions(conf)));
        mFieldNames = mReader.getSchema().getFieldNames();
        mRows = mReader.rows();
  
        mSchema = new OrcSchema(mReader);
      } catch (IOException e) {
        try {
          mCloser.close();
        } catch (IOException ioe) {
          e.addSuppressed(ioe);
        }
        throw e;
      }
    }
  
    /**
     * @param uri the alluxio uri of the orc file
     * @return new instance of OrcReader
     */
    public static OrcReader create(AlluxioURI uri) throws IOException {
      JobPath path = new JobPath(uri.getScheme(), uri.getAuthority().toString(), uri.getPath());
      return new OrcReader(path);
    }
  
    @Override
    public TableSchema getSchema() {
      return mSchema;
    }
  
    @Override
    public TableRow read() throws IOException {
      if (mCurrentBatch == null || mCurrentBatch.size <= mCurrentBatchPosition) {
        mCurrentBatch = mReader.getSchema().createRowBatch();
        mCurrentBatchPosition = 0;
        if (!mRows.nextBatch(mCurrentBatch)) {
          return null;
        }
      }
  
      return new OrcRow(mSchema, mCurrentBatch, mCurrentBatchPosition++, mFieldNames);
    }
  
    @Override
    public void close() throws IOException {
      mCloser.close();
    }
  }
  