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.examples.pi;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.datatorrent.api.Context.OperatorContext;
  import com.datatorrent.api.DefaultInputPort;
  import com.datatorrent.api.DefaultOutputPort;
  import com.datatorrent.common.util.BaseOperator;
  
  /**
   * This operator implements Monte Carlo estimation of pi. For points randomly distributed points on
   * square circle. pi ~= Number of points in circle/Total number of points * 4.
   *
   * @since 0.3.2
   */
  public class PiCalculateOperator extends BaseOperator
  {
    private transient int x = -1;
    private transient int y = -1;
    private int base;
    private long inArea = 0;
    private long totalArea = 0;
    public final transient DefaultInputPort<Integer> input = new DefaultInputPort<Integer>()
    {
      @Override
      public void process(Integer tuple)
      {
        if (x == -1) {
          x = tuple;
        } else {
          y = tuple;
          if (x * x + y * y <= base) {
            inArea++;
          }
          totalArea++;
          x = y = -1;
        }
      }
  
    };
    public final transient DefaultOutputPort<Double> output = new DefaultOutputPort<Double>();
  
    @Override
    public void setup(OperatorContext context)
    {
      logger.info("inArea {} totalArea {}", inArea, totalArea);
    }
  
    @Override
    public void beginWindow(long windowId)
    {
    }
  
    @Override
    public void endWindow()
    {
      output.emit((double)inArea / totalArea * 4);
    }
  
    public void setBase(int num)
    {
      base = num;
    }
  
    public int getBase()
    {
      return base;
    }
  
    private static Logger logger = LoggerFactory.getLogger(PiCalculateOperator.class);
  }
  