Parsing the data

NycTaxiCsvParser takes in the data from NycTaxiDataReader. It simply splits each line by a comma and outputs Map<String, String> containing individual fields. This is the definition of the input port of the NycTaxiCsvParser operator:

public final transient DefaultInputPort<String> input = new DefaultInputPort<String>() 
{ 
 @Override 
 public void process(String tuple) 
 { 
   String[] values = tuple.split(","); 
   Map<String, String> outputTuple = new HashMap<>(); 
   if (values.length > 18 && StringUtils.isNumeric(values[0])) { 
     outputTuple.put("pickup_time", values[1]); 
     outputTuple.put("pickup_lon", values[5]); 
     outputTuple.put("pickup_lat", values[6]); 
     outputTuple.put("total_fare", values[18]); 
     output.emit(outputTuple); 
   } 
 } 
}; 

As mentioned previously, we are only interested in the pickup time (Key pickup time), pickup lat-lon coordinate (Keys pickup lon and pickup lat), and total payment (Key...