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/*
* Copyright (c) 2009 Albert Kurucz.
*
* This file, SerialDate.java is part of JTStand.
*
* JTStand is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JTStand is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with GTStand. If not, see
* Requirement 1 : match at least what Excel does for dates;
* Requirement 2 : the date represented by the class is immutable;
*
* Why not just use java.util.Date? We will, when it makes sense. At times,
* java.util.Date can be *too* precise - it represents an instant in time,
* accurate to 1/1000th of a second (with the date itself depending on the
* time-zone). Sometimes we just want to represent a particular day (e.g. 21
* January 2015) without concerning ourselves about the time of day, or the
* time-zone, or anything else. That's what we've defined SerialDate for.
*
* You can call getInstance() to get a concrete subclass of SerialDate,
* without worrying about the exact implementation.
*
* @author David Gilbert
*/
public abstract class SerialDate implements Comparable,
Serializable,
MonthConstants {
/** For serialization. */
private static final long serialVersionUID = -293716040467423637L;
/** Date format symbols. */
public static final DateFormatSymbols
DATE_FORMAT_SYMBOLS = new SimpleDateFormat().getDateFormatSymbols();
/** The serial number for 1 January 1900. */
public static final int SERIAL_LOWER_BOUND = 2;
/** The serial number for 31 December 9999. */
public static final int SERIAL_UPPER_BOUND = 2958465;
/** The lowest year value supported by this date format. */
public static final int MINIMUM_YEAR_SUPPORTED = 1900;
/** The highest year value supported by this date format. */
public static final int MAXIMUM_YEAR_SUPPORTED = 9999;
/** Useful constant for Monday. Equivalent to java.util.Calendar.MONDAY. */
public static final int MONDAY = Calendar.MONDAY;
/**
* Useful constant for Tuesday. Equivalent to java.util.Calendar.TUESDAY.
*/
public static final int TUESDAY = Calendar.TUESDAY;
/**
* Useful constant for Wednesday. Equivalent to
* java.util.Calendar.WEDNESDAY.
*/
public static final int WEDNESDAY = Calendar.WEDNESDAY;
/**
* Useful constant for Thrusday. Equivalent to java.util.Calendar.THURSDAY.
*/
public static final int THURSDAY = Calendar.THURSDAY;
/** Useful constant for Friday. Equivalent to java.util.Calendar.FRIDAY. */
public static final int FRIDAY = Calendar.FRIDAY;
/**
* Useful constant for Saturday. Equivalent to java.util.Calendar.SATURDAY.
*/
public static final int SATURDAY = Calendar.SATURDAY;
/** Useful constant for Sunday. Equivalent to java.util.Calendar.SUNDAY. */
public static final int SUNDAY = Calendar.SUNDAY;
/** The number of days in each month in non leap years. */
static final int[] LAST_DAY_OF_MONTH =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/** The number of days in a (non-leap) year up to the end of each month. */
static final int[] AGGREGATE_DAYS_TO_END_OF_MONTH =
{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
/** The number of days in a year up to the end of the preceding month. */
static final int[] AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH =
{0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
/** The number of days in a leap year up to the end of each month. */
static final int[] LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_MONTH =
{0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};
/**
* The number of days in a leap year up to the end of the preceding month.
*/
static final int[]
LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH =
{0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366};
/** A useful constant for referring to the first week in a month. */
public static final int FIRST_WEEK_IN_MONTH = 1;
/** A useful constant for referring to the second week in a month. */
public static final int SECOND_WEEK_IN_MONTH = 2;
/** A useful constant for referring to the third week in a month. */
public static final int THIRD_WEEK_IN_MONTH = 3;
/** A useful constant for referring to the fourth week in a month. */
public static final int FOURTH_WEEK_IN_MONTH = 4;
/** A useful constant for referring to the last week in a month. */
public static final int LAST_WEEK_IN_MONTH = 0;
/** Useful range constant. */
public static final int INCLUDE_NONE = 0;
/** Useful range constant. */
public static final int INCLUDE_FIRST = 1;
/** Useful range constant. */
public static final int INCLUDE_SECOND = 2;
/** Useful range constant. */
public static final int INCLUDE_BOTH = 3;
/**
* Useful constant for specifying a day of the week relative to a fixed
* date.
*/
public static final int PRECEDING = -1;
/**
* Useful constant for specifying a day of the week relative to a fixed
* date.
*/
public static final int NEAREST = 0;
/**
* Useful constant for specifying a day of the week relative to a fixed
* date.
*/
public static final int FOLLOWING = 1;
/** A description for the date. */
private String description;
/**
* Default constructor.
*/
protected SerialDate() {
}
/**
* Returns true if the supplied integer code represents a
* valid day-of-the-week, and false otherwise.
*
* @param code the code being checked for validity.
*
* @return true if the supplied integer code represents a
* valid day-of-the-week, and false otherwise.
*/
public static boolean isValidWeekdayCode(final int code) {
switch(code) {
case SUNDAY:
case MONDAY:
case TUESDAY:
case WEDNESDAY:
case THURSDAY:
case FRIDAY:
case SATURDAY:
return true;
default:
return false;
}
}
/**
* Converts the supplied string to a day of the week.
*
* @param s a string representing the day of the week.
*
* @return -1 if the string is not convertable, the day of
* the week otherwise.
*/
public static int stringToWeekdayCode(String s) {
final String[] shortWeekdayNames
= DATE_FORMAT_SYMBOLS.getShortWeekdays();
final String[] weekDayNames = DATE_FORMAT_SYMBOLS.getWeekdays();
int result = -1;
s = s.trim();
for (int i = 0; i < weekDayNames.length; i++) {
if (s.equals(shortWeekdayNames[i])) {
result = i;
break;
}
if (s.equals(weekDayNames[i])) {
result = i;
break;
}
}
return result;
}
/**
* Returns a string representing the supplied day-of-the-week.
*
* Need to find a better approach.
*
* @param weekday the day of the week.
*
* @return a string representing the supplied day-of-the-week.
*/
public static String weekdayCodeToString(final int weekday) {
final String[] weekdays = DATE_FORMAT_SYMBOLS.getWeekdays();
return weekdays[weekday];
}
/**
* Returns an array of month names.
*
* @return an array of month names.
*/
public static String[] getMonths() {
return getMonths(false);
}
/**
* Returns an array of month names.
*
* @param shortened a flag indicating that shortened month names should
* be returned.
*
* @return an array of month names.
*/
public static String[] getMonths(final boolean shortened) {
if (shortened) {
return DATE_FORMAT_SYMBOLS.getShortMonths();
}
else {
return DATE_FORMAT_SYMBOLS.getMonths();
}
}
/**
* Returns true if the supplied integer code represents a valid month.
*
* @param code the code being checked for validity.
*
* @return true if the supplied integer code represents a
* valid month.
*/
public static boolean isValidMonthCode(final int code) {
switch(code) {
case JANUARY:
case FEBRUARY:
case MARCH:
case APRIL:
case MAY:
case JUNE:
case JULY:
case AUGUST:
case SEPTEMBER:
case OCTOBER:
case NOVEMBER:
case DECEMBER:
return true;
default:
return false;
}
}
/**
* Returns the quarter for the specified month.
*
* @param code the month code (1-12).
*
* @return the quarter that the month belongs to.
*/
public static int monthCodeToQuarter(final int code) {
switch(code) {
case JANUARY:
case FEBRUARY:
case MARCH: return 1;
case APRIL:
case MAY:
case JUNE: return 2;
case JULY:
case AUGUST:
case SEPTEMBER: return 3;
case OCTOBER:
case NOVEMBER:
case DECEMBER: return 4;
default: throw new IllegalArgumentException(
"SerialDate.monthCodeToQuarter: invalid month code.");
}
}
/**
* Returns a string representing the supplied month.
*
* The string returned is the long form of the month name taken from the
* default locale.
*
* @param month the month.
*
* @return a string representing the supplied month.
*/
public static String monthCodeToString(final int month) {
return monthCodeToString(month, false);
}
/**
* Returns a string representing the supplied month.
*
* The string returned is the long or short form of the month name taken
* from the default locale.
*
* @param month the month.
* @param shortened if true return the abbreviation of the
* month.
*
* @return a string representing the supplied month.
*/
public static String monthCodeToString(final int month,
final boolean shortened) {
// check arguments...
if (!isValidMonthCode(month)) {
throw new IllegalArgumentException(
"SerialDate.monthCodeToString: month outside valid range.");
}
final String[] months;
if (shortened) {
months = DATE_FORMAT_SYMBOLS.getShortMonths();
}
else {
months = DATE_FORMAT_SYMBOLS.getMonths();
}
return months[month - 1];
}
/**
* Converts a string to a month code.
*
* This method will return one of the constants JANUARY, FEBRUARY, ...,
* DECEMBER that corresponds to the string. If the string is not
* recognised, this method returns -1.
*
* @param s the string to parse.
*
* @return -1 if the string is not parseable, the month of the
* year otherwise.
*/
public static int stringToMonthCode(String s) {
final String[] shortMonthNames = DATE_FORMAT_SYMBOLS.getShortMonths();
final String[] monthNames = DATE_FORMAT_SYMBOLS.getMonths();
int result = -1;
s = s.trim();
// first try parsing the string as an integer (1-12)...
try {
result = Integer.parseInt(s);
}
catch (NumberFormatException e) {
// suppress
}
// now search through the month names...
if ((result < 1) || (result > 12)) {
for (int i = 0; i < monthNames.length; i++) {
if (s.equals(shortMonthNames[i])) {
result = i + 1;
break;
}
if (s.equals(monthNames[i])) {
result = i + 1;
break;
}
}
}
return result;
}
/**
* Returns true if the supplied integer code represents a valid
* week-in-the-month, and false otherwise.
*
* @param code the code being checked for validity.
* @return true if the supplied integer code represents a
* valid week-in-the-month.
*/
public static boolean isValidWeekInMonthCode(final int code) {
switch(code) {
case FIRST_WEEK_IN_MONTH:
case SECOND_WEEK_IN_MONTH:
case THIRD_WEEK_IN_MONTH:
case FOURTH_WEEK_IN_MONTH:
case LAST_WEEK_IN_MONTH: return true;
default: return false;
}
}
/**
* Determines whether or not the specified year is a leap year.
*
* @param yyyy the year (in the range 1900 to 9999).
*
* @return true if the specified year is a leap year.
*/
public static boolean isLeapYear(final int yyyy) {
if ((yyyy % 4) != 0) {
return false;
}
else if ((yyyy % 400) == 0) {
return true;
}
else if ((yyyy % 100) == 0) {
return false;
}
else {
return true;
}
}
/**
* Returns the number of leap years from 1900 to the specified year
* INCLUSIVE.
*
* Note that 1900 is not a leap year.
*
* @param yyyy the year (in the range 1900 to 9999).
*
* @return the number of leap years from 1900 to the specified year.
*/
public static int leapYearCount(final int yyyy) {
final int leap4 = (yyyy - 1896) / 4;
final int leap100 = (yyyy - 1800) / 100;
final int leap400 = (yyyy - 1600) / 400;
return leap4 - leap100 + leap400;
}
/**
* Returns the number of the last day of the month, taking into account
* leap years.
*
* @param month the month.
* @param yyyy the year (in the range 1900 to 9999).
*
* @return the number of the last day of the month.
*/
public static int lastDayOfMonth(final int month, final int yyyy) {
final int result = LAST_DAY_OF_MONTH[month];
if (month != FEBRUARY) {
return result;
}
else if (isLeapYear(yyyy)) {
return result + 1;
}
else {
return result;
}
}
/**
* Creates a new date by adding the specified number of days to the base
* date.
*
* @param days the number of days to add (can be negative).
* @param base the base date.
*
* @return a new date.
*/
public static SerialDate addDays(final int days, final SerialDate base) {
final int serialDayNumber = base.toSerial() + days;
return SerialDate.createInstance(serialDayNumber);
}
/**
* Creates a new date by adding the specified number of months to the base
* date.
*
* If the base date is close to the end of the month, the day on the result
* may be adjusted slightly: 31 May + 1 month = 30 June.
*
* @param months the number of months to add (can be negative).
* @param base the base date.
*
* @return a new date.
*/
public static SerialDate addMonths(final int months,
final SerialDate base) {
final int yy = (12 * base.getYYYY() + base.getMonth() + months - 1)
/ 12;
final int mm = (12 * base.getYYYY() + base.getMonth() + months - 1)
% 12 + 1;
final int dd = Math.min(
base.getDayOfMonth(), SerialDate.lastDayOfMonth(mm, yy)
);
return SerialDate.createInstance(dd, mm, yy);
}
/**
* Creates a new date by adding the specified number of years to the base
* date.
*
* @param years the number of years to add (can be negative).
* @param base the base date.
*
* @return A new date.
*/
public static SerialDate addYears(final int years, final SerialDate base) {
final int baseY = base.getYYYY();
final int baseM = base.getMonth();
final int baseD = base.getDayOfMonth();
final int targetY = baseY + years;
final int targetD = Math.min(
baseD, SerialDate.lastDayOfMonth(baseM, targetY)
);
return SerialDate.createInstance(targetD, baseM, targetY);
}
/**
* Returns the latest date that falls on the specified day-of-the-week and
* is BEFORE the base date.
*
* @param targetWeekday a code for the target day-of-the-week.
* @param base the base date.
*
* @return the latest date that falls on the specified day-of-the-week and
* is BEFORE the base date.
*/
public static SerialDate getPreviousDayOfWeek(final int targetWeekday,
final SerialDate base) {
// check arguments...
if (!SerialDate.isValidWeekdayCode(targetWeekday)) {
throw new IllegalArgumentException(
"Invalid day-of-the-week code."
);
}
// find the date...
final int adjust;
final int baseDOW = base.getDayOfWeek();
if (baseDOW > targetWeekday) {
adjust = Math.min(0, targetWeekday - baseDOW);
}
else {
adjust = -7 + Math.max(0, targetWeekday - baseDOW);
}
return SerialDate.addDays(adjust, base);
}
/**
* Returns the earliest date that falls on the specified day-of-the-week
* and is AFTER the base date.
*
* @param targetWeekday a code for the target day-of-the-week.
* @param base the base date.
*
* @return the earliest date that falls on the specified day-of-the-week
* and is AFTER the base date.
*/
public static SerialDate getFollowingDayOfWeek(final int targetWeekday,
final SerialDate base) {
// check arguments...
if (!SerialDate.isValidWeekdayCode(targetWeekday)) {
throw new IllegalArgumentException(
"Invalid day-of-the-week code."
);
}
// find the date...
final int adjust;
final int baseDOW = base.getDayOfWeek();
if (baseDOW > targetWeekday) {
adjust = 7 + Math.min(0, targetWeekday - baseDOW);
}
else {
adjust = Math.max(0, targetWeekday - baseDOW);
}
return SerialDate.addDays(adjust, base);
}
/**
* Returns the date that falls on the specified day-of-the-week and is
* CLOSEST to the base date.
*
* @param targetDOW a code for the target day-of-the-week.
* @param base the base date.
*
* @return the date that falls on the specified day-of-the-week and is
* CLOSEST to the base date.
*/
public static SerialDate getNearestDayOfWeek(final int targetDOW,
final SerialDate base) {
// check arguments...
if (!SerialDate.isValidWeekdayCode(targetDOW)) {
throw new IllegalArgumentException(
"Invalid day-of-the-week code."
);
}
// find the date...
final int baseDOW = base.getDayOfWeek();
int adjust = -Math.abs(targetDOW - baseDOW);
if (adjust >= 4) {
adjust = 7 - adjust;
}
if (adjust <= -4) {
adjust = 7 + adjust;
}
return SerialDate.addDays(adjust, base);
}
/**
* Rolls the date forward to the last day of the month.
*
* @param base the base date.
*
* @return a new serial date.
*/
public SerialDate getEndOfCurrentMonth(final SerialDate base) {
final int last = SerialDate.lastDayOfMonth(
base.getMonth(), base.getYYYY()
);
return SerialDate.createInstance(last, base.getMonth(), base.getYYYY());
}
/**
* Returns a string corresponding to the week-in-the-month code.
*
* Need to find a better approach.
*
* @param count an integer code representing the week-in-the-month.
*
* @return a string corresponding to the week-in-the-month code.
*/
public static String weekInMonthToString(final int count) {
switch (count) {
case SerialDate.FIRST_WEEK_IN_MONTH : return "First";
case SerialDate.SECOND_WEEK_IN_MONTH : return "Second";
case SerialDate.THIRD_WEEK_IN_MONTH : return "Third";
case SerialDate.FOURTH_WEEK_IN_MONTH : return "Fourth";
case SerialDate.LAST_WEEK_IN_MONTH : return "Last";
default :
return "SerialDate.weekInMonthToString(): invalid code.";
}
}
/**
* Returns a string representing the supplied 'relative'.
*
* Need to find a better approach.
*
* @param relative a constant representing the 'relative'.
*
* @return a string representing the supplied 'relative'.
*/
public static String relativeToString(final int relative) {
switch (relative) {
case SerialDate.PRECEDING : return "Preceding";
case SerialDate.NEAREST : return "Nearest";
case SerialDate.FOLLOWING : return "Following";
default : return "ERROR : Relative To String";
}
}
/**
* Factory method that returns an instance of some concrete subclass of
* {@link SerialDate}.
*
* @param day the day (1-31).
* @param month the month (1-12).
* @param yyyy the year (in the range 1900 to 9999).
*
* @return An instance of {@link SerialDate}.
*/
public static SerialDate createInstance(final int day, final int month,
final int yyyy) {
return new SpreadsheetDate(day, month, yyyy);
}
/**
* Factory method that returns an instance of some concrete subclass of
* {@link SerialDate}.
*
* @param serial the serial number for the day (1 January 1900 = 2).
*
* @return a instance of SerialDate.
*/
public static SerialDate createInstance(final int serial) {
return new SpreadsheetDate(serial);
}
/**
* Factory method that returns an instance of a subclass of SerialDate.
*
* @param date A Java date object.
*
* @return a instance of SerialDate.
*/
public static SerialDate createInstance(final java.util.Date date) {
final GregorianCalendar calendar = new GregorianCalendar();
calendar.setTime(date);
return new SpreadsheetDate(calendar.get(Calendar.DATE),
calendar.get(Calendar.MONTH) + 1,
calendar.get(Calendar.YEAR));
}
/**
* Returns the serial number for the date, where 1 January 1900 = 2 (this
* corresponds, almost, to the numbering system used in Microsoft Excel for
* Windows and Lotus 1-2-3).
*
* @return the serial number for the date.
*/
public abstract int toSerial();
/**
* Returns a java.util.Date. Since java.util.Date has more precision than
* SerialDate, we need to define a convention for the 'time of day'.
*
* @return this as java.util.Date.
*/
public abstract java.util.Date toDate();
/**
* Returns the description that is attached to the date. It is not
* required that a date have a description, but for some applications it
* is useful.
*
* @return The description (possibly null).
*/
public String getDescription() {
return this.description;
}
/**
* Sets the description for the date.
*
* @param description the description for this date (null
* permitted).
*/
public void setDescription(final String description) {
this.description = description;
}
/**
* Converts the date to a string.
*
* @return a string representation of the date.
*/
public String toString() {
return getDayOfMonth() + "-" + SerialDate.monthCodeToString(getMonth())
+ "-" + getYYYY();
}
/**
* Returns the year (assume a valid range of 1900 to 9999).
*
* @return the year.
*/
public abstract int getYYYY();
/**
* Returns the month (January = 1, February = 2, March = 3).
*
* @return the month of the year.
*/
public abstract int getMonth();
/**
* Returns the day of the month.
*
* @return the day of the month.
*/
public abstract int getDayOfMonth();
/**
* Returns the day of the week.
*
* @return the day of the week.
*/
public abstract int getDayOfWeek();
/**
* Returns the difference (in days) between this date and the specified
* 'other' date.
*
* The result is positive if this date is after the 'other' date and
* negative if it is before the 'other' date.
*
* @param other the date being compared to.
*
* @return the difference between this and the other date.
*/
public abstract int compare(SerialDate other);
/**
* Returns true if this SerialDate represents the same date as the
* specified SerialDate.
*
* @param other the date being compared to.
*
* @return true if this SerialDate represents the same date as
* the specified SerialDate.
*/
public abstract boolean isOn(SerialDate other);
/**
* Returns true if this SerialDate represents an earlier date compared to
* the specified SerialDate.
*
* @param other The date being compared to.
*
* @return true if this SerialDate represents an earlier date
* compared to the specified SerialDate.
*/
public abstract boolean isBefore(SerialDate other);
/**
* Returns true if this SerialDate represents the same date as the
* specified SerialDate.
*
* @param other the date being compared to.
*
* @return true if this SerialDate represents the same date
* as the specified SerialDate.
*/
public abstract boolean isOnOrBefore(SerialDate other);
/**
* Returns true if this SerialDate represents the same date as the
* specified SerialDate.
*
* @param other the date being compared to.
*
* @return true if this SerialDate represents the same date
* as the specified SerialDate.
*/
public abstract boolean isAfter(SerialDate other);
/**
* Returns true if this SerialDate represents the same date as the
* specified SerialDate.
*
* @param other the date being compared to.
*
* @return true if this SerialDate represents the same date
* as the specified SerialDate.
*/
public abstract boolean isOnOrAfter(SerialDate other);
/**
* Returns true if this {@link SerialDate} is within the
* specified range (INCLUSIVE). The date order of d1 and d2 is not
* important.
*
* @param d1 a boundary date for the range.
* @param d2 the other boundary date for the range.
*
* @return A boolean.
*/
public abstract boolean isInRange(SerialDate d1, SerialDate d2);
/**
* Returns true if this {@link SerialDate} is within the
* specified range (caller specifies whether or not the end-points are
* included). The date order of d1 and d2 is not important.
*
* @param d1 a boundary date for the range.
* @param d2 the other boundary date for the range.
* @param include a code that controls whether or not the start and end
* dates are included in the range.
*
* @return A boolean.
*/
public abstract boolean isInRange(SerialDate d1, SerialDate d2,
int include);
/**
* Returns the latest date that falls on the specified day-of-the-week and
* is BEFORE this date.
*
* @param targetDOW a code for the target day-of-the-week.
*
* @return the latest date that falls on the specified day-of-the-week and
* is BEFORE this date.
*/
public SerialDate getPreviousDayOfWeek(final int targetDOW) {
return getPreviousDayOfWeek(targetDOW, this);
}
/**
* Returns the earliest date that falls on the specified day-of-the-week
* and is AFTER this date.
*
* @param targetDOW a code for the target day-of-the-week.
*
* @return the earliest date that falls on the specified day-of-the-week
* and is AFTER this date.
*/
public SerialDate getFollowingDayOfWeek(final int targetDOW) {
return getFollowingDayOfWeek(targetDOW, this);
}
/**
* Returns the nearest date that falls on the specified day-of-the-week.
*
* @param targetDOW a code for the target day-of-the-week.
*
* @return the nearest date that falls on the specified day-of-the-week.
*/
public SerialDate getNearestDayOfWeek(final int targetDOW) {
return getNearestDayOfWeek(targetDOW, this);
}
}