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.mapred;
  
  import java.io.IOException;
  
  import org.apache.hadoop.io.NullWritable;
  import org.apache.hadoop.mapred.JobConf;
  import org.apache.hadoop.mapred.MapReduceBase;
  import org.apache.hadoop.mapred.Mapper;
  import org.apache.hadoop.mapred.OutputCollector;
  import org.apache.hadoop.mapred.Reporter;
  import org.apache.hadoop.util.ReflectionUtils;
  
  /**
   * Bridge between a {@link org.apache.hadoop.mapred.Mapper} and an
   * {@link AvroMapper}. Outputs are written directly when a job is map-only, but
   * are otherwise assumed to be pairs that are split.
   */
  class HadoopMapper<IN, OUT, K, V, KO, VO> extends MapReduceBase
      implements Mapper<AvroWrapper<IN>, NullWritable, KO, VO> {
  
    private AvroMapper<IN, OUT> mapper;
    private MapCollector<OUT, K, V, KO, VO> out;
    private boolean isMapOnly;
  
    @Override
    @SuppressWarnings("unchecked")
    public void configure(JobConf conf) {
      this.mapper = ReflectionUtils.newInstance(conf.getClass(AvroJob.MAPPER, AvroMapper.class, AvroMapper.class), conf);
      this.isMapOnly = conf.getNumReduceTasks() == 0;
    }
  
    @Override
    public void map(AvroWrapper<IN> wrapper, NullWritable value, OutputCollector<KO, VO> collector, Reporter reporter)
        throws IOException {
      if (this.out == null)
        this.out = new MapCollector<>(collector, isMapOnly);
      mapper.map(wrapper.datum(), out, reporter);
    }
  
    @Override
    public void close() throws IOException {
      this.mapper.close();
    }
  
  }
  