Main.java Source code

Introduction

Here is the source code for Main.java

Source

/**
 * This class provides some useful utility methods for date and time operations.
 * The implementations is done using the new date and time api in Java8.
 * 
 * @see add further links
 *
 * @author created: 7droids.org on 27.02.2014 20:45:58
 * @author last change: $Author: $ on $Date: $
 * @version $Revision: $
 */

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;

public class Main {
    public static void main(String[] argv) {
        System.out.println(getDSTType(LocalDate.now()));
    }

    enum DayType {
        STANDARD_TIME, DAYLIGHT_SAVING_TIME, TO_DAYLIGHT_SAVING_TIME, TO_STANDARD_TIME
    };

    /**
     * Checks if the type of the given date. Possible return values are standard
     * time, the date when to switch to daylight saving time (in Europe the last
     * Sunday in March), daylight saving time or the date when to switch back to
     * standard time (in Europe the last Sunday in October).
     * 
     * @return DayType
     * @param cal
     *          Date to check, cannot be null
     */
    public static DayType getDSTType(LocalDate cal) {
        DayType status = DayType.DAYLIGHT_SAVING_TIME;
        LocalDateTime testDate = cal.atStartOfDay();
        ZonedDateTime zdt = ZonedDateTime.of(testDate, ZoneId.systemDefault());
        // Find type of day
        if (zdt.getZone().getRules().isDaylightSavings(testDate.toInstant(zdt.getOffset())))
            status = DayType.DAYLIGHT_SAVING_TIME;
        else
            status = DayType.STANDARD_TIME;
        // Check the day after
        testDate = testDate.plusDays(1);
        zdt = ZonedDateTime.of(testDate, ZoneId.systemDefault());
        // Find type of day after
        if (zdt.getZone().getRules().isDaylightSavings(testDate.toInstant(zdt.getOffset()))) {
            if (status != DayType.DAYLIGHT_SAVING_TIME)
                status = DayType.TO_DAYLIGHT_SAVING_TIME;
        } else {
            if (status == DayType.DAYLIGHT_SAVING_TIME)
                status = DayType.TO_STANDARD_TIME;
        }
        return status;
    }
}