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/**
 * 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.lib.algo;

import java.util.HashMap;
import java.util.Map;

import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.api.annotation.OperatorAnnotation;
import com.datatorrent.api.annotation.OutputPortFieldAnnotation;
import com.datatorrent.api.annotation.Stateless;

import com.datatorrent.lib.util.BaseMatchOperator;
import com.datatorrent.lib.util.UnifierHashMap;

/**
 * This operator filters the incoming stream of key value pairs by obtaining the values corresponding to a specified key,
 * and comparing those values to a specified number. If a key value pair satisfies the comparison, then it is emitted.
 * 
 * A compare function is imposed based on the property "key", "value", and "cmp". If the tuple
 * passed the test, it is emitted on the output port match. The comparison is done by getting double
 * value from the Number. Both output ports are optional, but at least one has to be connected.
 * 
 * 
 * This module is a pass through

 * 

 * StateFull : No,  tuple is processed in current application window. 

 * Partitions : Yes,  match status is unified on output port. 

 * 

 * Ports:

 * data: expects Map<K,V extends Number>

 * match: emits HashMap<K,V>

 * 

 * Properties:

 * key: The key on which compare is done

 * value: The value to compare with

 * cmp: The compare function. Supported values are "lte", "lt", "eq", "neq", "gt", "gte". Default is "eq"

 * 

 * Specific compile time checks:

 * Key must be non empty

 * Value must be able to convert to a "double"

 * Compare string, if specified, must be one of "lte", "lt", "eq", "neq", "gt", "gte"

 * 

 * 
 *
 * @displayName Emit Matching Keval Pairs (Number)
 * @category Rules and Alerts
 * @tags filter, key value, numeric
 *
 * @since 0.3.2
 */
@Stateless
@OperatorAnnotation(partitionable = true)
public class MatchMap extends BaseMatchOperator
{
  /**
   * The input port which receives incoming key value pairs.
   */
  public final transient DefaultInputPort> data = new DefaultInputPort>()
  {
    /**
     * If tuple matches, tupleMatched is called, if not tupleNotMatched is called
     */
    @Override
    public void process(Map tuple)
    {
      V v = tuple.get(getKey());
      if (v == null) { // skip this tuple
        tupleNotMatched(tuple);
        return;
      }
      if (compareValue(v.doubleValue())) {
        tupleMatched(tuple);
      } else {
        tupleNotMatched(tuple);
      }
    }
  };

  /**
   * The output port which emits filtered key value pairs.
   */
  @OutputPortFieldAnnotation(optional = true)
  public final transient DefaultOutputPort> match = new DefaultOutputPort>()
  {
    @Override
    public Unifier> getUnifier()
    {
      return new UnifierHashMap();
    }
  };


  /**
   * Emits tuple if it. Call cloneTuple to allow users who have mutable objects to make a copy
   * @param tuple
   */
  public void tupleMatched(Map tuple)
  {
    match.emit(cloneTuple(tuple));
  }

  /**
   * No metric is done. Sub-classes can override and customize as needed
   * @param tuple
   */
  public void tupleNotMatched(Map tuple)
  {
  }


  /**
   * The key in the input tuple whose value will be used for comparison.
   * @param key The key in the input tuple whose value will be used for comparison.
   */
  @Override
  public void setKey(K key)
  {
    super.setKey(key);
  }
}