com.datatorrent.lib.math.ChangeAlertMap Maven / Gradle / Ivy

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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.math;

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

import javax.validation.constraints.Min;

import org.apache.commons.lang.mutable.MutableDouble;

import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.lib.util.BaseNumberKeyValueOperator;

/**
 * Operator stores  <key,value> pair in hash map across the windows for comparison and emits hash map of <key,percent change in value for each key> if percent change
 * exceeds preset threshold.
 * 
 *
 * StateFull : Yes, key/value pair in current window are stored for comparison in next window. 

 * Partition : No, will yield wrong result, base value won't be consistent across instances. 

 *
 * Ports:

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

 * alert: emits HashMap<K,HashMap<V,Double>>(1)

 * 

 * Properties:

 * threshold: The threshold of change between consecutive tuples of the same key that triggers an alert tuple

 * inverse: if set to true the key in the filter will block tuple

 * filterBy: List of keys to filter on

 * @displayName Change Alert Map
 * @category Rules and Alerts
 * @tags change, key value, numeric, percentage, map
 * @since 0.3.2
 */
public class ChangeAlertMap extends BaseNumberKeyValueOperator
{
  /**
   * Input data port that takes a map of <key,value>.
   */
  public final transient DefaultInputPort> data = new DefaultInputPort>()
  {
    /**
     * Process each key, compute change or percent, and emits it.
     */
    @Override
    public void process(Map tuple)
    {
      for (Map.Entry e: tuple.entrySet()) {
        MutableDouble val = basemap.get(e.getKey());
        if (!doprocessKey(e.getKey())) {
          continue;
        }
        if (val == null) { // Only process keys that are in the basemap
          val = new MutableDouble(e.getValue().doubleValue());
          basemap.put(cloneKey(e.getKey()), val);
          continue;
        }
        double change = e.getValue().doubleValue() - val.doubleValue();
        double percent = (change / val.doubleValue()) * 100;
        if (percent < 0.0) {
          percent = 0.0 - percent;
        }
        if (percent > percentThreshold) {
          HashMap dmap = new HashMap(1);
          dmap.put(cloneValue(e.getValue()), percent);
          HashMap> otuple = new HashMap>(1);
          otuple.put(cloneKey(e.getKey()), dmap);
          alert.emit(otuple);
        }
        val.setValue(e.getValue().doubleValue());
      }
    }
  };

  // Default "pass through" unifier works as tuple is emitted as pass through
  /**
   * Output port which emits a hashmap of key, percentage change.
   */
  public final transient DefaultOutputPort>> alert = new DefaultOutputPort>>();

  /**
   * basemap is a statefull field. It is retained across windows
   */
  private HashMap basemap = new HashMap();
  @Min(1)
  private double percentThreshold = 0.0;

  /**
   * getter function for threshold value
   * @return threshold value
   */
  @Min(1)
  public double getPercentThreshold()
  {
    return percentThreshold;
  }

  /**
   * setter function for threshold value
   */
  public void setPercentThreshold(double d)
  {
    percentThreshold = d;
  }
}