com.helger.datetime.holiday.CalendarUtil.java Source code

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Here is the source code for com.helger.datetime.holiday.CalendarUtil.java

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/**
 * Copyright (C) 2014-2015 Philip Helger (www.helger.com)
 * philip[at]helger[dot]com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.helger.datetime.holiday;

import java.util.HashSet;
import java.util.Set;

import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;

import org.joda.time.Chronology;
import org.joda.time.DateTimeConstants;
import org.joda.time.Interval;
import org.joda.time.LocalDate;
import org.joda.time.chrono.IslamicChronology;

import com.helger.datetime.PDTFactory;
import com.helger.datetime.PDTUtils;
import com.helger.datetime.config.PDTConfig;

/**
 * Utility class for date operations.
 *
 * @author Sven Diedrichsen
 * @author Philip Helger
 */
@Immutable
public final class CalendarUtil {
    private CalendarUtil() {
    }

    /**
     * Returns a set of gregorian dates within a gregorian year which equal the
     * islamic month and day. Because the islamic year is about 11 days shorter
     * than the gregorian there may be more than one occurrence of an islamic date
     * in an gregorian year. i.e.: In the gregorian year 2008 there were two 1/1.
     * They occurred on 1/10 and 12/29.
     *
     * @param nGregorianYear
     *        Year to convert
     * @param nIslamicMonth
     *        Month to convert
     * @param nIslamicDay
     *        Day to convert
     * @return List of gregorian dates for the islamic month/day.
     */
    public static Set<LocalDate> getIslamicHolidaysInGregorianYear(final int nGregorianYear,
            final int nIslamicMonth, final int nIslamicDay) {
        return getDatesFromChronologyWithinGregorianYear(nIslamicMonth, nIslamicDay, nGregorianYear,
                IslamicChronology.getInstanceUTC());
    }

    /**
     * Searches for the occurrences of a month/day in one chronology within one
     * gregorian year.
     *
     * @param nTargetMonth
     *        Target month
     * @param nTargetDay
     *        Target day
     * @param nGregorianYear
     *        Gregorian year
     * @param aTargetChronoUTC
     *        Target chronology
     * @return the list of gregorian dates.
     */
    @Nonnull
    public static Set<LocalDate> getDatesFromChronologyWithinGregorianYear(final int nTargetMonth,
            final int nTargetDay, final int nGregorianYear, final Chronology aTargetChronoUTC) {
        final Set<LocalDate> aHolidays = new HashSet<LocalDate>();
        final LocalDate aFirstGregorianDate = PDTFactory.createLocalDate(nGregorianYear, DateTimeConstants.JANUARY,
                1);
        final LocalDate aLastGregorianDate = PDTFactory.createLocalDate(nGregorianYear, DateTimeConstants.DECEMBER,
                31);

        final LocalDate aFirstTargetDate = new LocalDate(
                aFirstGregorianDate.toDateTimeAtStartOfDay(PDTConfig.getDateTimeZoneUTC()).getMillis(),
                aTargetChronoUTC);
        final LocalDate aLastTargetDate = new LocalDate(
                aLastGregorianDate.toDateTimeAtStartOfDay(PDTConfig.getDateTimeZoneUTC()).getMillis(),
                aTargetChronoUTC);

        final Interval aInterv = new Interval(
                aFirstTargetDate.toDateTimeAtStartOfDay(PDTConfig.getDateTimeZoneUTC()),
                aLastTargetDate.plusDays(1).toDateTimeAtStartOfDay(PDTConfig.getDateTimeZoneUTC()));

        for (int nTargetYear = aFirstTargetDate.getYear(); nTargetYear <= aLastTargetDate
                .getYear(); ++nTargetYear) {
            final LocalDate aLocalDate = new LocalDate(nTargetYear, nTargetMonth, nTargetDay, aTargetChronoUTC);
            if (aInterv.contains(aLocalDate.toDateTimeAtStartOfDay(PDTConfig.getDateTimeZoneUTC()))) {
                aHolidays.add(convertToGregorianDate(aLocalDate));
            }
        }
        return aHolidays;
    }

    /**
     * Takes converts the provided date into a date within the gregorian
     * chronology. If it is already a gregorian date it will return it.
     *
     * @param aDate
     *        Date to convert
     * @return Converted date
     */
    @Nonnull
    public static LocalDate convertToGregorianDate(@Nonnull final LocalDate aDate) {
        return PDTFactory.createLocalDateFromMillis(
                aDate.toDateTimeAtStartOfDay(PDTConfig.getDateTimeZoneUTC()).getMillis());
    }

    /**
     * Get the next working day based on the current day. If the current day is a
     * working day, the current day is returned. A working day is determined by:
     * it's not a weekend day (usually Saturday and Sunday).
     *
     * @return The next matching date.
     * @see PDTUtils#isWorkDay(LocalDate)
     */
    @Nonnull
    public static LocalDate getCurrentOrNextWorkDay() {
        LocalDate aDT = PDTFactory.getCurrentLocalDate();
        while (!PDTUtils.isWorkDay(aDT))
            aDT = aDT.plusDays(1);
        return aDT;
    }
}