gistfile1.txt

/**
* Build a flight schedule where we can identify a closest airport for a plane to land.
* A plane is in the air. The pilot uses this program to search for the closest airport in the area where it can land.  The airport should * be able to accomodate the size of the plane. For example, if the plane size is 737, the airport must be a large one.
*/
Class Airport {
    double latitude;
    double longitude;
    boolean isAvailable;
    //getters()
    //setters()
}

public class Utils {
    /**
    * @method return distance of 2 Geo Locations
    * */
    private double EARTH_RADIUS = 6378.137;
    private static double rad(double d)
    {
       return d * Math.PI / 180.0;
    }

    public static double getDistance(double lat1, double lng1, double lat2, double lng2)
    {
       double radLat1 = rad(lat1);
       double radLat2 = rad(lat2);
       double a = radLat1 - radLat2;
       double b = rad(lng1) - rad(lng2);

       double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) +
        Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
       s = s * EARTH_RADIUS;
       s = Math.round(s * 100) / 100.0;
       return s;
    }
}


public class GeoComparator implements Comparator<Airport> { 
    private double currentLatitude;
    private double currentLongitude;
    public GeoComparator(double curLat, double curLng) {
        this.currentLatitude = curLat;
        this.currentLongitude = curLng;
    } 
  
    @Override  
    public int compare(Airport airport1, Airport airport2) {  
        double distance1 =  Utils.getDistance(currentLatitude, currentLongitude, airport1.getLatitude(), airport2.getLongitude()); 
        double distance2 =  Utils.getDistance(currentLatitude, currentLongitude, airport2.getLatitude(), airport2.getLongitude()); 
        if(distance1 > distance2){  
            return 1;  
        }else if(distance1 < distance2){  
            return -1;  
        }else{  
            return 0;  
        }  
    }  
}  

public Airport getCloestAvailableAirport(Plane plane) {
    List<Airport> list = getListFromGoogle(plane.getCurrentLatitude(), plane.getcurrentLongitude()); //dummy method,  get airport list with gro location from google places api, JSON, convert them to model Airport 

    Collections.sort(list,new GeoComparator(plane.getCurrentLatitude(), plane.getcurrentLongitude())); 
    for (Airport airport : list) {
        if (airport.isAvailable) {
            return airport;
        }
    }
    throw new IllegalArgumentException("No Available Airport at this time");
}