[NP] TimeTable

import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.util.*;

class UnsupportedFormatException extends Exception {
    String msg;

    public UnsupportedFormatException(String msg) {
        this.msg = msg;
    }

    @Override
    public String getMessage() {
        return msg;
    }
}

class InvalidTimeException extends Exception {
    /* Using Exception's default getMessage() */
    public InvalidTimeException(String msg) {
        super(msg);
    }
}

enum TimeFormat {
    FORMAT_24, FORMAT_AMPM
}

class Time implements Comparable<Time> {
    int hours;
    int minutes;

    public Time(String time) throws UnsupportedFormatException, InvalidTimeException {
        time = time.replace(".", ":");

        String parts[] = time.split(":");
        if (parts.length < 2) {
            throw new UnsupportedFormatException(time);
        }

        int temp = Integer.parseInt(parts[0]);
        if (temp < 0 || temp > 24) {
            throw new InvalidTimeException(time);
        }
        this.hours = temp;

        temp = Integer.parseInt(parts[1]);
        if (temp < 0 || temp > 60) {
            throw new InvalidTimeException(time);
        }
        this.minutes = temp;

    }

    public String formatAMPM() {
        String ampm;
        /* 00:00 to 11:59 is AM */
        if (hours == 0) {
            hours += 12;
            ampm = "AM";
        } else if (hours < 12) {
            ampm = "AM";
        /* 12:00 to 23:59 is AM */
        } else if (hours == 12) {
            ampm = "PM";
        } else {
            hours -= 12;
            ampm = "PM";
        }
        return String.format("%2d:%02d %s", hours, minutes, ampm);
    }

    public String format24() {
        return String.format("%2d:%02d", hours, minutes);
    }

    @Override
    public String toString() {
        return format24();
    }

    @Override
    public int compareTo(Time that) {
        /* It's always in the context of this */
        if (this.hours < that.hours) {
            return -1;
        } else if (this.hours > that.hours) {
            return 1;
        } else if (this.hours == that.hours) {
            if (this.minutes < that.minutes) {
                return -1;
            } else if (this.minutes > that.minutes) {
                return 1;
            } else {
                return 0;
            }
        }
        return 0;

        /* Simpler Way */
        /*return Integer.compare(this.hours * 60 + this.minutes, that.hours * 60 + that.minutes);*/
    }
}

class TimeTable {
    ArrayList<Time> times;

    public TimeTable() {
        times = new ArrayList<>();
    }

    public void readTimes(InputStream inputStream) throws UnsupportedFormatException, InvalidTimeException {
        Scanner input = new Scanner(inputStream);
        while (input.hasNext()) {
            Time time = new Time(input.next());
            times.add(time);
        }

    }

    public void writeTimes(OutputStream outputStream, TimeFormat format) {
        PrintWriter pw = new PrintWriter(outputStream);
        Collections.sort(times);
        if (format.equals(TimeFormat.FORMAT_24)) {
            for (Time time : times) {
                pw.println(time.format24());
            }
        } else {
            for (Time time : times) {
                pw.println(time.formatAMPM());
            }
        }
        /*
        4: Don't close a printWriter because
        if you close the System.out then you can't print at all.
        It's better to you flush it.
        */
        pw.flush();
    }
}

public class TimesTest {

    public static void main(String[] args) {
        TimeTable timeTable = new TimeTable();
        try {
            timeTable.readTimes(System.in);
        } catch (UnsupportedFormatException e) {
            System.out.println("UnsupportedFormatException: " + e.getMessage());
        } catch (InvalidTimeException e) {
            System.out.println("InvalidTimeException: " + e.getMessage());
        }
        System.out.println("24 HOUR FORMAT");
        timeTable.writeTimes(System.out, TimeFormat.FORMAT_24);
        System.out.println("AM/PM FORMAT");
        timeTable.writeTimes(System.out, TimeFormat.FORMAT_AMPM);
    }

}