Javaで国民の祝日とかの名前を取得するやつ(1948/7/20～2013/9/8現在)

Holiday.java

package com.oboenikui.holiday;

import java.util.Calendar;

public class Holiday {

    /**
     * calで渡された日が祝日かどうかを返します。
     * @param cal 判別したい日
     * @return 祝日ならtrue、そうでなければfalseを返します。
     */
    public static boolean isHoliday(Calendar cal){
        return isNormalHoliday(cal)||isLenu(cal)||isNationalHoliday(cal);
    }


    /**
     * 国民の祝日であればその名前を返します。もしも異なる場合は返り値はnullとなります。
     * @param cal 名前を取得したい日
     * @return 国民の祝日の名前
     */
    public static String getHolidayName(Calendar cal){
        Calendar first_day = Calendar.getInstance();
        first_day.set(1948, 7, 20);
        if(first_day.compareTo(cal)>=0) return null;
        int year = cal.get(Calendar.YEAR);
        int date = cal.get(Calendar.DAY_OF_MONTH);
        switch (cal.get(Calendar.MONTH)) {
        case Calendar.JANUARY:
            switch (date) {
            case 1:
                return "元日";
            case 15:
                if(year<=1999) return "成人の日";
            default:
                if(year>=2000&&isMondayHoliday(cal,2)) return "成人の日";
            }
            break;
        case Calendar.FEBRUARY:
            if (year>=1967&&date==11) return "建国記念の日";
            break;
        case Calendar.MARCH:
            if(isVernalEquinoxHoliday(cal)) return "春分の日";
            break;
        case Calendar.APRIL:
            if(date==29){
                if(year<=1988) return "天皇誕生日";
                else if(year<=2006) return "みどりの日";
                else return "昭和の日";
            }
            break;
        case Calendar.MAY:
            switch (date) {
            case 3:
                return "憲法記念日";
            case 4:
                if(year>=2007) return "みどりの日";
                break;
            case 5:
                return "こどもの日";
            default:
                break;
            }
            break;
        case Calendar.JULY:
            if(year>=1996&&year<=2002&&date==20||year>=2003&&isMondayHoliday(cal, 3)) return "海の日";
            break;
        case Calendar.SEPTEMBER:
            if(year>=1966&&year<=2002&&date==15||year>=2003&&isMondayHoliday(cal, 3)) return "敬老の日";
            else if(isAutumnEquinoxHoliday(cal)) return "秋分の日";
            break;
        case Calendar.OCTOBER:
            if(year>=1966&&year<=1999&&date==10||year>=2000&&isMondayHoliday(cal, 2)) return "体育の日";
            break;
        case Calendar.NOVEMBER:
            switch(date){
            case 3:
                return "文化の日";
            case 23:
                return "勤労感謝の日";
            default:
                break;
            }
            break;
        case Calendar.DECEMBER:
            if(year>=1989&&date==23) return "天皇誕生日";
            break;
        default:
            break;
        }
        if(isLenu(cal)) return "振替休日";
        if(isNationalHoliday(cal)) return "国民の休日";
        return null;
    }

    private static boolean isNormalHoliday(Calendar cal){
        Calendar first_day = Calendar.getInstance();
        first_day.set(1948, 7, 20);
        if(first_day.compareTo(cal)>=0) return false;
        int year = cal.get(Calendar.YEAR);
        int day = cal.get(Calendar.DAY_OF_MONTH);
        switch (cal.get(Calendar.MONTH)) {
        case Calendar.JANUARY:
            return day==1||(year<=1999&&day==15)||(year>=2000&&isMondayHoliday(cal,2));
        case Calendar.FEBRUARY:
            return year>=1967&&day==11;
        case Calendar.MARCH:
            return isVernalEquinoxHoliday(cal);
        case Calendar.APRIL:
            return day==29;
        case Calendar.MAY:
            return (day==3||day==5)||year>=2007&&day==4;
        case Calendar.JULY:
            return year>=1996&&year<=2002&&day==20||year>=2003&&isMondayHoliday(cal, 3);
        case Calendar.SEPTEMBER:
            return year>=1966&&year<=2002&&day==15||year>=2003&&isMondayHoliday(cal, 3)||isAutumnEquinoxHoliday(cal);
        case Calendar.OCTOBER:
            return year>=1966&&year<=1999&&day==10||year>=2000&&isMondayHoliday(cal, 2);
        case Calendar.NOVEMBER:
            return day==3||day==23;
        case Calendar.DECEMBER:
            return year>=1989&&day==23;
        default:
            return false;
        }
    }

    private static boolean isAutumnEquinoxHoliday(Calendar cal){
        int year = cal.get(Calendar.YEAR);
        if(cal.get(Calendar.MONTH)!=Calendar.SEPTEMBER||year<1948) return false;
        int day_of_month = cal.get(Calendar.DAY_OF_MONTH);
        switch(year%4){
        case 0:
            return (year<=2008&&day_of_month==23)||(year>2008&&day_of_month==22);
        case 1:
            return (year<=2041&&day_of_month==23)||(year>2041&&day_of_month==22);
        case 2:
            return (year<=2074&&day_of_month==23)||(year>2074&&day_of_month==22);
        case 3:
            return (year<=1979&&day_of_month==24)||(year>1979&&day_of_month==23);
        default:
            return false;
        }
    }

    private static boolean isVernalEquinoxHoliday(Calendar cal){
        int year = cal.get(Calendar.YEAR);
        if(cal.get(Calendar.MONTH)!=Calendar.MARCH||year<1949) return false;
        int day_of_month = cal.get(Calendar.DAY_OF_MONTH);
        switch(year%4){
        case 0:
            return (year<=1956&&day_of_month==21)||(year>1956&&year<=2088&&day_of_month==20)||(year>2088&&day_of_month==19);
        case 1:
            return (year<=1989&&day_of_month==21)||(year>1989&&day_of_month==20);
        case 2:
            return (year<=2022&&day_of_month==21)||(year>2022&&day_of_month==20);
        case 3:
            return (year<=1923&&day_of_month==22)||(year>1923&&year<=2055&&day_of_month==21)||(year>2055&&day_of_month==20);
        default:
            return false;
        }
    }

    private static boolean isMondayHoliday(Calendar cal, int i){
        int day = cal.get(Calendar.DAY_OF_MONTH);
        return cal.get(Calendar.DAY_OF_WEEK)==Calendar.MONDAY&&day>=i*7-6&&day<=i*7;
    }

    private static boolean isLenu(Calendar cal){
        Calendar operation = Calendar.getInstance();
        operation.set(1973, 4, 12);
        if(operation.compareTo(cal)>=0)return false;
        Calendar cal_before = (Calendar) cal.clone();
        cal_before.add(Calendar.DAY_OF_YEAR, -1);
        if(cal.get(Calendar.YEAR)>=2007){
            boolean lenu = true;
            int i;
            for(i=cal.get(Calendar.DAY_OF_WEEK);i>=1;i--){
                lenu&=isNormalHoliday(cal_before);
                cal_before.add(Calendar.DAY_OF_YEAR, -1);
            }
            return lenu;
        } else {
            return isNormalHoliday(cal_before)&&cal.get(Calendar.DAY_OF_WEEK)==Calendar.MONDAY;
        }
    }

    private static boolean isNationalHoliday(Calendar cal){
        Calendar operation = Calendar.getInstance();
        operation.set(1985, 12, 27);
        if(operation.compareTo(cal)>=0)return false;
        Calendar cal_before = (Calendar) cal.clone();
        Calendar cal_after = (Calendar) cal.clone();
        cal_before.add(Calendar.DAY_OF_YEAR, -1);
        cal_after.add(Calendar.DAY_OF_YEAR, 1);
        return isNormalHoliday(cal_before)&&isNormalHoliday(cal_after);
    }
}