examples/mroperator/src/main/java/org/apache/apex/examples/mroperator/ReduceOperator.java

/**
 * 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
 *
 *   http://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.apex.examples.mroperator;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.apex.malhar.lib.util.KeyHashValPair;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapred.Counters;
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 com.datatorrent.api.Context.OperatorContext;
import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.api.Operator;

/**
 * <p>ReduceOperator class.</p>
 *
 * @since 0.9.0
 */
@SuppressWarnings({ "deprecation", "unused" })
public class ReduceOperator<K1, V1, K2, V2> implements Operator
{
  private static final Logger logger = LoggerFactory.getLogger(ReduceOperator.class);

  private Class<? extends Reducer<K1, V1, K2, V2>> reduceClass;
  private transient Reducer<K1, V1, K2, V2> reduceObj;
  private transient Reporter reporter;
  private OutputCollector<K2, V2> outputCollector;
  private String configFile;

  public Class<? extends Reducer<K1, V1, K2, V2>> getReduceClass()
  {
    return reduceClass;
  }

  public void setReduceClass(Class<? extends Reducer<K1, V1, K2, V2>> reduceClass)
  {
    this.reduceClass = reduceClass;
  }

  public String getConfigFile()
  {
    return configFile;
  }

  public void setConfigFile(String configFile)
  {
    this.configFile = configFile;
  }

  private int numberOfMappersRunning = -1;
  private int operatorId;

  public final transient DefaultInputPort<KeyHashValPair<Integer, Integer>> inputCount = new DefaultInputPort<KeyHashValPair<Integer, Integer>>()
  {
    @Override
    public void process(KeyHashValPair<Integer, Integer> tuple)
    {
      logger.info("processing {}", tuple);
      if (numberOfMappersRunning == -1) {
        numberOfMappersRunning = tuple.getValue();
      } else {
        numberOfMappersRunning += tuple.getValue();
      }

    }

  };

  public final transient DefaultOutputPort<KeyHashValPair<K2, V2>> output = new DefaultOutputPort<KeyHashValPair<K2, V2>>();
  private Map<K1, List<V1>> cacheObject;
  public final transient DefaultInputPort<KeyHashValPair<K1, V1>> input = new DefaultInputPort<KeyHashValPair<K1, V1>>()
  {
    @Override
    public void process(KeyHashValPair<K1, V1> tuple)
    {
      // logger.info("processing tupple {}",tuple);
      List<V1> list = cacheObject.get(tuple.getKey());
      if (list == null) {
        list = new ArrayList<V1>();
        list.add(tuple.getValue());
        cacheObject.put(tuple.getKey(), list);
      } else {
        list.add(tuple.getValue());
      }
    }

  };

  @Override
  public void setup(OperatorContext context)
  {
    reporter = new ReporterImpl(ReporterImpl.ReporterType.Reducer, new Counters());
    if (context != null) {
      operatorId = context.getId();
    }
    cacheObject = new HashMap<K1, List<V1>>();
    outputCollector = new OutputCollectorImpl<K2, V2>();
    if (reduceClass != null) {
      try {
        reduceObj = reduceClass.newInstance();
      } catch (Exception e) {
        logger.info("can't instantiate object {}", e.getMessage());
        throw new RuntimeException(e);
      }
      Configuration conf = new Configuration();
      InputStream stream = null;
      if (configFile != null && configFile.length() > 0) {
        logger.info("system /{}", configFile);
        stream = ClassLoader.getSystemResourceAsStream("/" + configFile);
        if (stream == null) {
          logger.info("system {}", configFile);
          stream = ClassLoader.getSystemResourceAsStream(configFile);
        }
      }
      if (stream != null) {
        logger.info("found our stream... so adding it");
        conf.addResource(stream);
      }
      reduceObj.configure(new JobConf(conf));
    }

  }

  @Override
  public void teardown()
  {

  }

  @Override
  public void beginWindow(long windowId)
  {

  }

  @Override
  public void endWindow()
  {
    if (numberOfMappersRunning == 0) {
      for (Map.Entry<K1, List<V1>> e : cacheObject.entrySet()) {
        try {
          reduceObj.reduce(e.getKey(), e.getValue().iterator(), outputCollector, reporter);
        } catch (IOException e1) {
          logger.info(e1.getMessage());
          throw new RuntimeException(e1);
        }
      }
      List<KeyHashValPair<K2, V2>> list = ((OutputCollectorImpl<K2, V2>)outputCollector).getList();
      for (KeyHashValPair<K2, V2> e : list) {
        output.emit(e);
      }
      list.clear();
      cacheObject.clear();
      numberOfMappersRunning = -1;
    }
  }

}