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.tether;
  
  import java.io.IOException;
  import java.util.Iterator;
  
  import org.apache.hadoop.io.NullWritable;
  import org.apache.hadoop.mapred.JobConf;
  import org.apache.hadoop.mapred.OutputCollector;
  import org.apache.hadoop.mapred.Reducer;
  import org.apache.hadoop.mapred.Reporter;
  
  import org.apache.avro.mapred.AvroJob;
  
  class TetherReducer implements Reducer<TetherData, NullWritable, TetherData, NullWritable> {
  
    private JobConf job;
    private TetheredProcess process;
    private boolean error;
  
    @Override
    public void configure(JobConf job) {
      this.job = job;
    }
  
    @Override
    public void reduce(TetherData datum, Iterator<NullWritable> ignore,
        OutputCollector<TetherData, NullWritable> collector, Reporter reporter) throws IOException {
      try {
        if (process == null) {
          process = new TetheredProcess(job, collector, reporter);
          process.inputClient.configure(TaskType.REDUCE, AvroJob.getMapOutputSchema(job).toString(),
              AvroJob.getOutputSchema(job).toString());
        }
        process.inputClient.input(datum.buffer(), datum.count());
      } catch (IOException e) {
        error = true;
        throw e;
      } catch (Exception e) {
        error = true;
        throw new IOException(e);
      }
    }
  
    /**
     * Handle the end of the input by closing down the application.
     */
    @Override
    public void close() throws IOException {
      if (process == null)
        return;
      try {
        if (error)
          process.inputClient.abort();
        else
          process.inputClient.complete();
        process.outputService.waitForFinish();
      } catch (InterruptedException e) {
        throw new IOException(e);
      } finally {
        process.close();
      }
    }
  }
  