flink 注册函数示例

public class IsInNYC extends ScalarFunction {

    // geo boundaries of the area of NYC
    private static double LON_EAST = -73.7;
    private static double LON_WEST = -74.05;
    private static double LAT_NORTH = 41.0;
    private static double LAT_SOUTH = 40.5;

    public static boolean eval(float lon, float lat) {
        return isInNYC(lon, lat);
    }

    public static boolean isInNYC(float lon, float lat) {

        return !(lon > LON_EAST || lon < LON_WEST) &&
                !(lat > LAT_NORTH || lat < LAT_SOUTH);
    }
}