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.math;
  
  import javax.validation.constraints.Min;
  
  import org.apache.apex.malhar.lib.util.BaseNumberValueOperator;
  import org.apache.apex.malhar.lib.util.KeyValPair;
  
  import com.datatorrent.api.DefaultInputPort;
  import com.datatorrent.api.DefaultOutputPort;
  
  /**
   * Compares consecutive input data values, emits &lt;value,percent change value&gt; pair on alert output port, if percent change exceeds certain thresh hold value.
   * <p>
   * Operator is StateFull since current value is stored for comparison in next window. <br>
   * This operator can not be partitioned, partitioning will result in inconsistent base value
   * across replicated copies.
   * <br>
   *
   * <b>Ports</b>:<br>
   * <b>data</b>: expects KeyValPair&lt;K,V extends Number&gt;<br>
   * <b>alert</b>: emits KeyValPair&lt;K,KeyValPair&lt;V,Double&gt;&gt;(1)<br>
   * <br>
   * <b>Properties</b>:<br>
   * <b>threshold</b>: The threshold of change between consecutive tuples of the
   * same key that triggers an alert tuple<br>
   * <b>inverse</b>: if set to true the key in the filter will block tuple<br>
   * <b>filterBy</b>: List of keys to filter on<br>
   * <br>
   * <b>Specific compile time checks</b>: None<br>
   * <b>Specific run time checks</b>: None<br>
   * <br>
   * @displayName Change Alert
   * @category Rules and Alerts
   * @tags change, key value, numeric, percentage
   * @since 0.3.3
   * @deprecated
   */
  @Deprecated
  public class ChangeAlert<V extends Number> extends BaseNumberValueOperator<V>
  {
    /**
     * Input port that takes in a number.
     */
    public final transient DefaultInputPort<V> data = new DefaultInputPort<V>()
    {
      /**
       * Process each key, compute change or percent, and emit it. If we get 0 as
       * tuple next will be skipped.
       */
      @Override
      public void process(V tuple)
      {
        double tval = tuple.doubleValue();
        if (baseValue == 0) { // Avoid divide by zero, Emit an error tuple?
          baseValue = tval;
          return;
        }
        double change = tval - baseValue;
        double percent = (change / baseValue) * 100;
        if (percent < 0.0) {
          percent = 0.0 - percent;
        }
        if (percent > percentThreshold) {
          KeyValPair<V, Double> kv = new KeyValPair<V, Double>(cloneKey(tuple),
              percent);
          alert.emit(kv);
        }
        baseValue = tval;
      }
    };
  
  
    /**
     * Output port which emits a key value pair.
     */
    public final transient DefaultOutputPort<KeyValPair<V, Double>> alert = new DefaultOutputPort<KeyValPair<V, Double>>();
  
    /**
     * baseValue is a state full field. It is retained across windows
     */
    private double baseValue = 0;
    @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;
    }
  }
  