/*
* Copyright (C) 2010-2011 Stephen Ostermiller
* https://ostermiller.org/contact.pl?regarding=Java+Utilities
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* See LICENSE.txt for details.
*/
package com.Ostermiller.util;
import java.util.Calendar;
/**
* Extend years like '99 to 1999 based on dates around the current date.
*
* @author Stephen Ostermiller https://ostermiller.org/contact.pl?regarding=Java+Utilities
* @since ostermillerutils 1.08.00
*/
public class YearExtensionAround implements YearExtensionPolicy {
private static final int NEAREST_ALLOWED_YEARS_IN_PAST = 50;
/**
* Extend a two digit year to the nearest year that ends in
* those two digits.
* <p>
* When it is the year 2000:
* <ul>
* <li> 50 to 1950
* <li> 99 to 1999
* <li> 00 to 2000
* <li> 01 to 2001
* </ul>
*
* @since ostermillerutils 1.08.00
*/
public static final YearExtensionAround NEAREST = new YearExtensionAround(
NEAREST_ALLOWED_YEARS_IN_PAST
);
/**
* Extend a two digit year to the nearest year that ends in
* those two digits.
* <p>
* When it is the year 2000:
* <ul>
* <li> 50 to 1950
* <li> 99 to 1999
* <li> 00 to 2000
* <li> 01 to 2001
* </ul>
*
* @param currentYear the current year
* @since ostermillerutils 1.08.00
*/
public static final YearExtensionAround getNearest(int currentYear){
return new YearExtensionAround(NEAREST_ALLOWED_YEARS_IN_PAST, currentYear);
}
private static final int LATEST_ALLOWED_YEARS_IN_PAST = 99;
/**
* Extend a two digit year to the nearest year that ends in
* those two digits.
* <p>
* When it is the year 2000:
* <ul>
* <li> 01 to 1901
* <li> 49 to 1949
* <li> 50 to 1950
* <li> 99 to 1999
* <li> 00 to 2000
* </ul>
*
* @since ostermillerutils 1.08.00
*/
public static final YearExtensionAround LATEST = new YearExtensionAround(
LATEST_ALLOWED_YEARS_IN_PAST
);
/**
* Extend a two digit year to the nearest year that ends in
* those two digits.
* <p>
* When it is the year 2000:
* <ul>
* <li> 01 to 1901
* <li> 49 to 1949
* <li> 50 to 1950
* <li> 99 to 1999
* <li> 00 to 2000
* </ul>
*
* @param currentYear the current year
* @since ostermillerutils 1.08.00
*/
public static final YearExtensionAround getLatest(int currentYear){
return new YearExtensionAround(LATEST_ALLOWED_YEARS_IN_PAST, currentYear);
}
private static final int CENTURY_ALLOWED_YEARS_IN_PAST = 0;
private static final int CENTURY_1900_START = 1900;
/**
* Extend a two digit year to a year in the 1900s
* <ul>
* <li> 00 to 1900
* <li> 01 to 1901
* <li> 49 to 1949
* <li> 50 to 1950
* <li> 99 to 1999
* </ul>
*
* @since ostermillerutils 1.08.00
*/
public static final YearExtensionAround CENTURY_1900 = new YearExtensionAround(
CENTURY_ALLOWED_YEARS_IN_PAST,
CENTURY_1900_START
);
private static final int CENTURY_2000_START = 2000;
/**
* Extend a two digit year to a year in the 2000s
* <ul>
* <li> 00 to 2000
* <li> 01 to 2001
* <li> 49 to 2049
* <li> 50 to 2050
* <li> 99 to 2099
* </ul>
*
* @since ostermillerutils 1.08.00
*/
public static final YearExtensionAround CENTURY_2000 = new YearExtensionAround(
CENTURY_ALLOWED_YEARS_IN_PAST,
CENTURY_2000_START
);
private int currentYear;
private int baseYear;
private int allowedYearsInPast;
/**
* Create a year extension nearest policy with the current year taken from the
* system time.
*
* @since ostermillerutils 1.08.00
*/
public YearExtensionAround(int allowedYearsInPast){
this(allowedYearsInPast, Calendar.getInstance().get(Calendar.YEAR));
}
/**
* Create a year extension nearest policy with the given current year
*
* @param currentYear full year eg 2000
*
* @since ostermillerutils 1.08.00
*/
public YearExtensionAround(int allowedYearsInPast, int currentYear){
setAllowedYearsInPast(allowedYearsInPast);
setCurrentYear(currentYear);
}
/**
* Number of years in the past to allow dates
* @param allowedYearsInPast number between 0 and 99
*/
public void setAllowedYearsInPast(int allowedYearsInPast){
if (allowedYearsInPast < 0 || allowedYearsInPast >= 100){
throw new IllegalArgumentException(
"Allowed years in past must be in 0 to 99 range"
);
}
this.allowedYearsInPast = allowedYearsInPast;
}
/**
* Set the current year.
*
* @param currentYear full year eg 2000
*
* @since ostermillerutils 1.08.00
*/
public void setCurrentYear(int currentYear){
this.currentYear = currentYear;
calculateBaseYear();
}
private void calculateBaseYear(){
baseYear = currentYear/100*100 - 100;
}
/**
* Extend a two digit year to the nearest year that ends in
* those two digits.
* <p>
* Will choose a year within 100 years of the current year.
* Whether the year is in the past or future is determined
* by how many years are allowed in the past.
*
* @since ostermillerutils 1.08.00
*/
public int extendYear(int twoDigitYear) {
int year = twoDigitYear + baseYear;
if (currentYear - year > allowedYearsInPast) year += 100;
return year;
}
}