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.malhar.contrib.misc.algo;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.apex.malhar.lib.util.BaseKeyValueOperator;
  import org.apache.apex.malhar.lib.util.UnifierHashMap;
  
  import com.datatorrent.api.DefaultInputPort;
  import com.datatorrent.api.DefaultOutputPort;
  import com.datatorrent.api.annotation.OperatorAnnotation;
  
  /**
   * This operator computes and emits distinct key,val pairs (i.e drops duplicates).
   * <p>
   * Computes and emits distinct key,val pairs (i.e drops duplicates)
   * </p>
   * <p>
   * This is a pass through operator<br>
   * <br>
   * This module is same as a "FirstOf" metric on any key,val pair. At end of window all data is flushed.<br>
   * <br>
   * <b>StateFull : Yes, </b> tuple are compare across application window(s). <br>
   * <b>Partitions : Yes, </b> distinct output is unified by unifier hash map operator. <br>
   * <br>
   * <b>Ports</b>:<br>
   * <b>data</b>: Input data port expects Map&lt;K,V&gt;<br>
   * <b>distinct</b>: Output data port, emits HashMap&lt;K,V&gt;(1)<br>
   * <br>
   * </p>
   *
   * @displayName Distinct Key Value Merge
   * @category Stream Manipulators
   * @tags filter, unique, key value
   *
   * @since 0.3.2
   * @deprecated
   */
  
  @Deprecated
  @OperatorAnnotation(partitionable = true)
  public class DistinctMap<K, V> extends BaseKeyValueOperator<K, V>
  {
    /**
     * The input port on which key value pairs are received.
     */
    public final transient DefaultInputPort<Map<K, V>> data = new DefaultInputPort<Map<K, V>>()
    {
      /**
       * Process HashMap<K,V> tuple on input port data, and emits if match not found. Updates the cache
       * with new key,val pair
       */
      @Override
      public void process(Map<K, V> tuple)
      {
        for (Map.Entry<K, V> e: tuple.entrySet()) {
          HashMap<V, Object> vals = mapkeyval.get(e.getKey());
          if ((vals == null) || !vals.containsKey(e.getValue())) {
            HashMap<K, V> otuple = new HashMap<K, V>(1);
            otuple.put(cloneKey(e.getKey()), cloneValue(e.getValue()));
            distinct.emit(otuple);
            if (vals == null) {
              vals = new HashMap<V, Object>();
              mapkeyval.put(cloneKey(e.getKey()), vals);
            }
            vals.put(cloneValue(e.getValue()), null);
          }
        }
      }
    };
  
    /**
     * The output port on which distinct key value pairs are emitted.
     */
    public final transient DefaultOutputPort<HashMap<K, V>> distinct = new DefaultOutputPort<HashMap<K, V>>()
    {
      @Override
      public Unifier<HashMap<K, V>> getUnifier()
      {
        return new UnifierHashMap<K, V>();
      }
    };
  
  
    protected HashMap<K, HashMap<V, Object>> mapkeyval = new HashMap<K, HashMap<V, Object>>();
  
    /**
     * Clears the cache/hash
     */
    @Override
    public void endWindow()
    {
      mapkeyval.clear();
    }
  }
  