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 org.apache.apex.malhar.lib.util.AbstractBaseFrequentKeyValueMap;
  
  import com.datatorrent.api.DefaultOutputPort;
  
  /**
   * This operator filters the incoming stream of key value pairs by finding the value or values (if there is a tie),
   * for each key, that occur the fewest number of times within each window.&nbsp;
   * Each key and its corresponding least values are emitted at the end of each window.
   * <p>
   * Occurrences of all values for each key is counted and at the end of window the least frequent values are emitted on output port least per key.
   * </p>
   * <p>
   * This module is an end of window module<br>
   * <br>
   * <b>Ports</b>:<br>
   * <b>data</b>: expects Map&lt;K,V&gt;<br>
   * <b>least</b>: Output port, emits HashMap&lt;K,HashMap&lt;V,Integer&gt;&gt;(1)<br>
   * <br>
   * <b>Properties</b>: None<br>
   * <br>
   * <b>Compile time checks</b>: None<br>
   * <b>Specific run time checks</b>: None <br>
   * <br>
   * <b>Benchmarks</b>: Blast as many tuples as possible in inline mode<br>
   * <table border="1" cellspacing=1 cellpadding=1 summary="Benchmark table for LeastFrequentKeyValueMap&lt;K,V&gt; operator template">
   * <tr><th>In-Bound</th><th>Out-bound</th><th>Comments</th></tr>
   * <tr><td><b>&gt; 30 Million K,V pairs/s</b></td><td>Emits only 1 tuple per window per key</td><td>In-bound throughput is the main determinant of performance.
   * The benchmark was done with immutable objects. If K or V are mutable the benchmark may be lower</td></tr>
   * </table><br>
   * </p>
   * <p>
   * <b>Function Table (K=String,V=Integer);</b>:
   * <table border="1" cellspacing=1 cellpadding=1 summary="Function table for LeastFrequentKeyValueMap&lt;K,V&gt; operator template">
   * <tr><th rowspan=2>Tuple Type (api)</th><th>In-bound (process)</th><th>Out-bound (emit)</th></tr>
   * <tr><th><i>data</i>(Map&lt;K,V&gt;)</th><th><i>least</i>(HashMap&lt;K,HashMap&lt;Integer&gt;&gt;)</th></tr>
   * <tr><td>Begin Window (beginWindow())</td><td>N/A</td><td>N/A</td></tr>
   * <tr><td>Data (process())</td><td>{a=1,b=5,c=110}</td><td></td></tr>
   * <tr><td>Data (process())</td><td>{a=55,c=2000,b=45}</td><td></td></tr>
   * <tr><td>Data (process())</td><td>{d=2}</td><td></td></tr>
   * <tr><td>Data (process())</td><td>{a=55,b=5,c=22}</td><td></td></tr>
   * <tr><td>Data (process())</td><td>{h=20,a=2,z=5}</td><td></td></tr>
   * <tr><td>Data (process())</td><td>{a=4,c=110}</td><td></td></tr>
   * <tr><td>Data (process())</td><td>{a=4,z=5}</td><td></td></tr>
   * <tr><td>End Window (endWindow())</td><td>N/A</td><td>{a={1=1,2=1},b={45=1},c={2000=1,22=1},d={2=1},h={20=1},z={5=2}</td></tr>
   * </table>
   * <br>
   * <br>
   * </p>
   *
   * @displayName Emit Least Frequent Keyval Pair
   * @category Rules and Alerts
   * @tags filter, key value, count
   * @deprecated
   * @since 0.3.2
   */
  @Deprecated
  public class LeastFrequentKeyValueMap<K, V> extends AbstractBaseFrequentKeyValueMap<K, V>
  {
    /**
     * The output port on which the least frequent key value pairs are emitted.
     */
    public final transient DefaultOutputPort<HashMap<K, HashMap<V, Integer>>> least = new DefaultOutputPort<HashMap<K, HashMap<V, Integer>>>();
  
    /**
     * returns val1 < val2
     * @param val1
     * @param val2
     * @return val1 < val2
     */
    @Override
    public boolean compareValue(int val1, int val2)
    {
      return (val1 < val2);
    }
  
    /**
     * Emits tuple on port "least"
     * @param tuple
     */
    @Override
    public void emitTuple(HashMap<K, HashMap<V, Integer>> tuple)
    {
      least.emit(tuple);
    }
  }
  