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 com.datatorrent.apps.logstream;
  
  import java.util.Map;
  
  import javax.validation.constraints.NotNull;
  
  import com.datatorrent.common.util.BaseOperator;
  import com.datatorrent.api.DefaultInputPort;
  import com.datatorrent.api.DefaultOutputPort;
  
  /**
   * Sums the value of the selected dimension from the map over application window
   *
   * @param <K> dimension to select from map
   * @param <V> value to be summed
   * @since 0.9.4
   */
  public class SumItemFromMapOperator<K, V> extends BaseOperator
  {
    @NotNull
    private K sumDimension;
    private long sum = 0L;
  
    public void setSumDimension(K sumDimension)
    {
      this.sumDimension = sumDimension;
    }
  
    public final transient DefaultInputPort<Map<K, V>> mapInput = new DefaultInputPort<Map<K, V>>()
    {
      @Override
      public void process(Map<K, V> tuple)
      {
        V val = tuple.get(sumDimension);
        if (val != null) {
          sum += Long.valueOf((String)val);
        }
      }
  
    };
    public final transient DefaultOutputPort<String> output = new DefaultOutputPort<String>();
  
    @Override
    public void endWindow()
    {
      output.emit(String.valueOf(sum));
      sum = 0L;
    }
  
  }
  