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.avro.mapreduce;
  
  import java.io.IOException;
  
  import org.apache.avro.Schema;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.avro.hadoop.io.AvroSequenceFile;
  import org.apache.hadoop.io.SequenceFile;
  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.hadoop.mapreduce.lib.input.SequenceFileInputFormat;
  
  /**
   * An input format for reading from AvroSequenceFiles (sequence files that
   * support Avro data).
   *
   * @param <K> The input key type.
   * @param <V> The input value type.
   */
  public class AvroSequenceFileInputFormat<K, V> extends SequenceFileInputFormat<K, V> {
    /** {@inheritDoc} */
    @Override
    public RecordReader<K, V> createRecordReader(InputSplit inputSplit, TaskAttemptContext context) throws IOException {
      return new AvroSequenceFileRecordReader();
    }
  
    /**
     * Reads records from a SequenceFile that supports Avro data.
     *
     * <p>
     * This class is based on Hadoop's SequenceFileRecordReader, modified to
     * construct an AvroSequenceFile.Reader instead of a SequenceFile.Reader.
     * </p>
     */
    protected class AvroSequenceFileRecordReader extends RecordReader<K, V> {
      private SequenceFile.Reader mReader;
      private long mStart;
      private long mEnd;
      private boolean mHasMoreData;
      private K mCurrentKey;
      private V mCurrentValue;
  
      /** {@inheritDoc} */
      @Override
      public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        FileSplit fileSplit = (FileSplit) split;
        Configuration conf = context.getConfiguration();
        Path path = fileSplit.getPath();
        FileSystem fs = path.getFileSystem(conf);
  
        // Configure the SequenceFile reader.
        AvroSequenceFile.Reader.Options options = new AvroSequenceFile.Reader.Options().withFileSystem(fs)
            .withInputPath(path).withConfiguration(conf);
        Schema keySchema = AvroJob.getInputKeySchema(conf);
        if (null != keySchema) {
          options.withKeySchema(keySchema);
        }
        Schema valueSchema = AvroJob.getInputValueSchema(conf);
        if (null != valueSchema) {
          options.withValueSchema(valueSchema);
        }
  
        mReader = new AvroSequenceFile.Reader(options);
        mEnd = fileSplit.getStart() + fileSplit.getLength();
  
        if (fileSplit.getStart() > mReader.getPosition()) {
          // Sync to the beginning of the input split.
          mReader.sync(fileSplit.getStart());
        }
  
        mStart = mReader.getPosition();
        mHasMoreData = mStart < mEnd;
      }
  
      /** {@inheritDoc} */
      @Override
      @SuppressWarnings("unchecked")
      public boolean nextKeyValue() throws IOException, InterruptedException {
        if (!mHasMoreData) {
          return false;
        }
        long pos = mReader.getPosition();
        mCurrentKey = (K) mReader.next(mCurrentKey);
        if (null == mCurrentKey || (pos >= mEnd && mReader.syncSeen())) {
          mHasMoreData = false;
          mCurrentKey = null;
          mCurrentValue = null;
        } else {
          mCurrentValue = (V) mReader.getCurrentValue(mCurrentValue);
        }
        return mHasMoreData;
      }
  
      /** {@inheritDoc} */
      @Override
      public K getCurrentKey() {
        return mCurrentKey;
      }
  
      /** {@inheritDoc} */
      @Override
      public V getCurrentValue() {
        return mCurrentValue;
      }
  
      /** {@inheritDoc} */
      @Override
      public float getProgress() throws IOException {
        if (mEnd == mStart) {
          return 0.0f;
        } else {
          return Math.min(1.0f, (mReader.getPosition() - mStart) / (float) (mEnd - mStart));
        }
      }
  
      /** {@inheritDoc} */
      @Override
      public synchronized void close() throws IOException {
        mReader.close();
      }
    }
  }
  