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
   *
   *   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.distributeddistinct;
  
  import java.io.Serializable;
  
  import org.apache.apex.malhar.lib.algo.UniqueValueCount;
  import org.apache.apex.malhar.lib.algo.UniqueValueCount.InternalCountOutput;
  import org.apache.apex.malhar.lib.codec.KryoSerializableStreamCodec;
  import org.apache.apex.malhar.lib.io.ConsoleOutputOperator;
  import org.apache.hadoop.conf.Configuration;
  
  import com.datatorrent.api.Context;
  import com.datatorrent.api.DAG;
  import com.datatorrent.api.DefaultOutputPort;
  import com.datatorrent.api.StreamingApplication;
  import com.datatorrent.api.annotation.ApplicationAnnotation;
  
  /**
   * This application demonstrates the UniqueValueCount operator. It uses an input operator which generates random key
   * value pairs and emits them to the UniqueValueCount operator which keeps track of the unique values per window. It
   * then emits the values to the StatefulUniqueCount which uses a combination of a cache and database to keep track of
   * the overall unique values and outputs the resulting unique value count to the ConsoleOutputOperator.
   *
   * @since 1.0.4
   */
  @ApplicationAnnotation(name = "StatefulDistinctCount")
  public class StatefulApplication implements StreamingApplication
  {
    @SuppressWarnings("unchecked")
    @Override
    public void populateDAG(DAG dag, Configuration conf)
    {
      RandomKeyValGenerator randGen = dag.addOperator("RandomGenerator", new RandomKeyValGenerator());
      UniqueValueCount<Integer> valCount = dag.addOperator("UniqueCounter", new UniqueValueCount<Integer>());
      ConsoleOutputOperator consOut = dag.addOperator("Console", new ConsoleOutputOperator());
      IntegerUniqueValueCountAppender uniqueUnifier = dag.addOperator("StatefulUniqueCounter", new IntegerUniqueValueCountAppender());
      dag.getOperatorMeta("StatefulUniqueCounter").getMeta(uniqueUnifier.input).getAttributes().put(Context.PortContext.STREAM_CODEC, new KeyBasedStreamCodec());
  
      @SuppressWarnings("rawtypes")
      DefaultOutputPort valOut = valCount.output;
      @SuppressWarnings("rawtypes")
      DefaultOutputPort uniqueOut = uniqueUnifier.output;
  
      dag.addStream("Events", randGen.outport, valCount.input);
      dag.addStream("Unified", valOut, uniqueUnifier.input);
      dag.addStream("Result", uniqueOut, consOut.input);
    }
  
    public static class KeyBasedStreamCodec extends KryoSerializableStreamCodec<InternalCountOutput<Integer>> implements Serializable
    {
      @Override
      public int getPartition(InternalCountOutput<Integer> t)
      {
        return t.getKey().hashCode();
      }
  
      private static final long serialVersionUID = 201407231527L;
    }
  }
  