com.datatorrent.lib.multiwindow.MultiWindowRangeKeyVal 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.multiwindow;

import java.util.Map;

import javax.validation.constraints.Min;

import com.datatorrent.lib.math.RangeKeyVal;
import com.datatorrent.lib.util.HighLow;
import com.datatorrent.lib.util.KeyValPair;

/**
 * A range operator of KeyValPair schema which calculates range across multiple streaming windows.
 * 
 * This is an end window operator which emits only at Nth window. 

 * 

 * StateFull : Yes, computes across multiple windows. 

 * Partitions : Yes, high/low are unified on output port. 

 * 

 * Ports:

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

 * range: emits KeyValPair<K,HighLow<V>>

 * 

 * Properties:

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

 * filterBy: List of keys to filter on

 * 

 * Specific compile time checks: None

 * Specific run time checks: None

 * windowSize i.e. N: Number of streaming windows that define application window.

 * 

 *
 * @displayName Multi Window Range Key Value
 * @category Stats and Aggregations
 * @tags key value, range, numeric
 * @since 0.3.2
 */
public class MultiWindowRangeKeyVal extends RangeKeyVal
{
  /**
   * Number of streaming window after which tuple got emitted.
   */
  @Min(2)
  private int windowSize = 2;
  private long windowCount = 0;

  public void setWindowSize(int windowSize)
  {
    this.windowSize = windowSize;
  }

  /**
   * Emits range for each key at application window boundary. If no data is received, no emit is done
   * Clears the internal data before return
   */
  @SuppressWarnings({ "unchecked", "rawtypes" })
  @Override
  public void endWindow()
  {
    boolean emit = (++windowCount) % windowSize == 0;

    if (!emit) {
      return;
    }

    for (Map.Entry e: high.entrySet()) {
      HighLow hl = new HighLow();
      hl.setHigh(getValue(e.getValue().doubleValue()));
      hl.setLow(getValue(low.get(e.getKey()).doubleValue())); // cannot be null

      range.emit(new KeyValPair(e.getKey(), hl));
    }
    clearCache();
  }
}