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
   *
   *     https://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.trevni.avro.mapreduce;
  
  import java.io.IOException;
  
  import org.apache.avro.mapreduce.AvroJob;
  import org.apache.avro.reflect.ReflectData;
  import org.apache.hadoop.mapreduce.InputSplit;
  import org.apache.hadoop.mapreduce.RecordReader;
  import org.apache.hadoop.mapreduce.TaskAttemptContext;
  import org.apache.hadoop.mapreduce.lib.input.FileSplit;
  import org.apache.trevni.avro.AvroColumnReader;
  import org.apache.trevni.avro.HadoopInput;
  
  /**
   * Abstract base class for <code>RecordReader</code>s that read Trevni container
   * files.
   *
   * @param <K> The type of key the record reader should generate.
   * @param <V> The type of value the record reader should generate.
   * @param <T> The type of the entries within the Trevni container file being
   *            read.
   */
  public abstract class AvroTrevniRecordReaderBase<K, V, T> extends RecordReader<K, V> {
  
    /** The Trevni file reader */
    private AvroColumnReader<T> reader;
  
    /** Number of rows in the Trevni file */
    private float rows;
  
    /** The current row number being read in */
    private long row;
  
    /** A reusable object to hold records of the Avro container file. */
    private T mCurrentRecord;
  
    /** {@inheritDoc} */
    @Override
    public void initialize(InputSplit inputSplit, TaskAttemptContext context) throws IOException, InterruptedException {
      final FileSplit file = (FileSplit) inputSplit;
      context.setStatus(file.toString());
  
      final AvroColumnReader.Params params = new AvroColumnReader.Params(
          new HadoopInput(file.getPath(), context.getConfiguration()));
      params.setModel(ReflectData.get());
  
      if (AvroJob.getInputKeySchema(context.getConfiguration()) != null) {
        params.setSchema(AvroJob.getInputKeySchema(context.getConfiguration()));
      }
  
      reader = new AvroColumnReader<>(params);
      rows = reader.getRowCount();
    }
  
    /** {@inheritDoc} */
    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
      if (!reader.hasNext())
        return false;
      mCurrentRecord = reader.next();
      row++;
      return true;
    }
  
    /**
     * Gets the current record read from the Trevni container file.
     *
     * <p>
     * Calling <code>nextKeyValue()</code> moves this to the next record.
     * </p>
     *
     * @return The current Trevni record (may be null if no record has been read).
     */
    protected T getCurrentRecord() {
      return mCurrentRecord;
    }
  
    /** {@inheritDoc} */
    @Override
    public void close() throws IOException {
      reader.close();
    }
  
    /** {@inheritDoc} */
    @Override
    public float getProgress() throws IOException, InterruptedException {
      return row / rows;
    }
  }
  