DailyProgrammer, Weekly #17, Saturday Birthday

SaturdayBirthday.java

import java.time.DayOfWeek;
import java.time.Duration;
import java.time.LocalDate;
import java.time.Period;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;

public class SaturdayBirthday {

    public static class Info {

        private static final DateTimeFormatter dtf
                = DateTimeFormatter.ofPattern("EEE, d MMM yyyy");

        private final LocalDate birthday;
        private final LocalDate current;
        private final LocalDate future;

        public Info(LocalDate current, LocalDate birthday, LocalDate future) {
            this.current = current;
            this.birthday = birthday;
            this.future = future;
        }

        @Override
        public String toString() {
            return dtf.format(future) + " (" + getDaysToFuture()
                    + " days, age " + getAgeFuture() + ")";
        }

        private long getDaysToFuture() {
            Duration duration = Duration.between(current.atTime(0, 0),
                    future.atTime(0, 0));
            return duration.toDays();
        }

        private int getAgeFuture() {
            Period period = Period.between(birthday, future);
            return period.getYears();
        }
    }

    public Info solve(String bday) {
        DateTimeFormatter[] formats = {
            DateTimeFormatter.ofPattern("yyyy-MM-dd"),
            DateTimeFormatter.ofPattern("d MMM yyyy"),
            DateTimeFormatter.ofPattern("dd.MM.yyyy"),
            DateTimeFormatter.ofPattern("MMM d, yyyy")
        };
        for (DateTimeFormatter dft : formats) {
            try {
                LocalDate birthday = LocalDate.parse(bday, dft);
                LocalDate now = LocalDate.now();
                int offset = 0;
                while (true) {
                    LocalDate test = birthday.plusYears(offset);
                    if (test.isAfter(now)
                            && test.getDayOfWeek() == DayOfWeek.SATURDAY) {
                        Info info = new Info(now, birthday, test);
                        return info;
                    }
                    offset++;
                }
            } catch (DateTimeParseException dtpe) {
            }
        }
        return null;
    }

    public static void main(String[] args) {
        SaturdayBirthday problem = new SaturdayBirthday();
        String[] bdays = {"11 May 1968", "11.05.1968", "1968-05-11",
            "May 11, 1968"};
        for (String bday : bdays) {
            SaturdayBirthday.Info info = problem.solve(bday);
            if (info != null) {
                System.out.println(bday + " -> " + info);
            } else {
                System.out.println(bday + " -> <parse error>");
            }
        }
    }
}

output:
11 May 1968 -> Sat, 11 May 2019 (1634 days, age 51)
11.05.1968 -> Sat, 11 May 2019 (1634 days, age 51)
1968-05-11 -> Sat, 11 May 2019 (1634 days, age 51)
May 11, 1968 -> Sat, 11 May 2019 (1634 days, age 51)