Time Validation (WACABS).java

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;

public class HelloWorld {

	public static void main(String args[]) throws ParseException {

		System.out.print("\n" + "# 1 (SAT/SUN) " + getValidity("Sat", "Sun", "19:00:00", "21:00:00") + "\n");
		System.out.print("\n" + "# 2 (SUN/MON) " + getValidity("Sun", "Mon", "17:00:00", "18:00:00") + "\n");
		System.out.print("\n" + "# 3 (MON/TUE) " + getValidity("Mon", "Tue", "17:00:00", "18:00:00") + "\n");
		System.out.print("\n" + "# 4 (TUE/WED) " + getValidity("Tue", "Wed", "17:00:00", "18:00:00") + "\n");
		System.out.print("\n" + "# 5 (WED/THU) " + getValidity("Wed", "Thu", "17:00:00", "18:00:00") + "\n");
		System.out.print("\n" + "# 6 (THU/FRI) " + getValidity("Thu", "Fri", "17:00:00", "18:00:00") + "\n");
		System.out.print("\n" + "# 7 (FRI/SAT) " + getValidity("Fri", "Sat", "17:00:00", "18:00:00") + "\n");
		System.out.print("\n" + "# 8 (SAT/SAT) " + getValidity("Sat", "Sat", "20:00:00", "20:00:00") + "\n");
	}

	/**
	 * Process the current, start & end date/time validation
	 * 
	 * @param start_date
	 * @param end_date
	 * @param start_time
	 * @param end_time
	 * @return
	 * @throws ParseException
	 */
	public static boolean getValidity(String start_day, String end_day, String begin_time, String end_time)
			throws ParseException {

		final DateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
		Calendar cal_current = Calendar.getInstance();
		Calendar cal_start = Calendar.getInstance();
		Calendar cal_end = Calendar.getInstance();

		// Todo: set a static value to current day and set it in the calender object
		cal_current.set(Calendar.DAY_OF_WEEK, getDayCount("Sat"));

		// get the dates from day name
		// start_date
		cal_start.set(Calendar.DAY_OF_WEEK, getDayCount(start_day));
		// end_date
		cal_end.set(Calendar.DAY_OF_WEEK, getDayCount(end_day));

		// initialize the date objects
		//Date current_date = formatter.parse(formatter.format(cal_current.getTime()));
		Date temp_current_date = formatter.parse(formatter.format(cal_current.getTime()));
		Date start_date = formatter.parse(formatter.format(cal_start.getTime()));
		Date temp_end_date = formatter.parse(formatter.format(cal_end.getTime()));

		// add days to date object if the end time is earlier than the start
		// time
		if (temp_end_date.compareTo(start_date) < 0) {
			cal_end.add(Calendar.DATE, 7);
		} /*else if (temp_end_date.compareTo(temp_current_date) < 0){
			cal_current.add(Calendar.DATE, -7);
		}*/
		// final date object after adding days 
		Date end_date = formatter.parse(formatter.format(cal_end.getTime()));
		
		if (end_date.compareTo(temp_current_date) < 0){
			cal_current.add(Calendar.DATE, -7);
		}

		Date current_date = formatter.parse(formatter.format(cal_current.getTime()));
		
		System.out.println("Current Date: " + current_date);
		System.out.println("Start Date: " + start_date);
		System.out.println("End Date: " + end_date);

		if ((current_date.after(start_date) || current_date.equals(start_date))
				&& (current_date.before(end_date) || current_date.equals(end_date))) {

			try {
				SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");
				format.setTimeZone(TimeZone.getTimeZone("GMT+8"));
				Date today = Calendar.getInstance().getTime();
				String datePresent = format.format(today);

				Date dStart = new Date();
				Date dStop = new Date();
				Date dPresent = new Date();

				dStart = format.parse(begin_time);
				dStop = format.parse(end_time);
				dPresent = format.parse(datePresent);
				
				// convert the time into seconds for comparing 
				long current_time = TimeUnit.MILLISECONDS.toSeconds(dPresent.getTime());
				long start_time = TimeUnit.MILLISECONDS.toSeconds(dStart.getTime());
				long stop_time = TimeUnit.MILLISECONDS.toSeconds(dStop.getTime());

				if (current_date.equals(start_date)) {
					if (current_time >= start_time && current_time <= stop_time) {
						return true;
					} else {
						return false;
					}
				} else {
					if (current_time <= stop_time) {
						return true;
					} else {
						return false;
					}
				}

				// Todo: date validation without time
				// return true;

			} catch (Exception e) {
				e.printStackTrace();
			}
		}

		return false;
	}

	/**
	 * Get the appropriate day's Integer value from a day name
	 * 
	 * @param calender
	 * @param day
	 * @return
	 */
	public static int getDayCount(String day) {
		int count = 1;
		if (day.matches("Sun")) {
			count = Calendar.SUNDAY;
		} else if (day.matches("Mon")) {
			count = Calendar.MONDAY;
		} else if (day.matches("Tue")) {
			count = Calendar.TUESDAY;
		} else if (day.matches("Wed")) {
			count = Calendar.WEDNESDAY;
		} else if (day.matches("Thu")) {
			count = Calendar.THURSDAY;
		} else if (day.matches("Fri")) {
			count = Calendar.FRIDAY;
		} else if (day.matches("Sat")) {
			count = Calendar.SATURDAY;
		}
		return count;
	}

	/**
	 * Convert a given time to GMT+8
	 * 
	 * @param time
	 * @return
	 */
	public String toGMT(String time) {

		// first convert the received string to date
		Date date = new Date();

		// creating DateFormat for converting time from local timezone to GMT
		DateFormat format = new SimpleDateFormat("HH:mm:ss", Locale.ENGLISH);
		try {
			date = format.parse(time);
		} catch (ParseException e) {
			e.printStackTrace();
		}
		// getting GMT timezone
		format.setTimeZone(TimeZone.getTimeZone("GMT+8"));

		return format.format(date).toString();
	}
}