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/*
 *  Copyright 2001-2005 Stephen Colebourne
 *
 *  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 org.joda.time.chrono;

import org.joda.time.Chronology;
import org.joda.time.DateTimeConstants;

/**
 * Abstract Chronology for implementing chronologies based on Gregorian/Julian formulae.
 * Most of the utility methods required by subclasses are package-private,
 * reflecting the intention that they be defined in the same package.
 * 

* BasicGJChronology is thread-safe and immutable, and all subclasses must * be as well. * * @author Stephen Colebourne * @author Brian S O'Neill * @author Guy Allard * @since 1.2, refactored from CommonGJChronology */ abstract class BasicGJChronology extends BasicChronology { /** Serialization lock */ private static final long serialVersionUID = 538276888268L; // These arrays are NOT public. We trust ourselves not to alter the array. // They use zero-based array indexes so the that valid range of months is // automatically checked. private static final int[] MIN_DAYS_PER_MONTH_ARRAY = { 31,28,31,30,31,30,31,31,30,31,30,31 }; private static final int[] MAX_DAYS_PER_MONTH_ARRAY = { 31,29,31,30,31,30,31,31,30,31,30,31 }; private static final long[] MIN_TOTAL_MILLIS_BY_MONTH_ARRAY; private static final long[] MAX_TOTAL_MILLIS_BY_MONTH_ARRAY; private static final long FEB_29 = (31L + 29 - 1) * DateTimeConstants.MILLIS_PER_DAY; static { MIN_TOTAL_MILLIS_BY_MONTH_ARRAY = new long[12]; MAX_TOTAL_MILLIS_BY_MONTH_ARRAY = new long[12]; long minSum = 0; long maxSum = 0; for (int i = 0; i < 11; i++) { long millis = MIN_DAYS_PER_MONTH_ARRAY[i] * (long)DateTimeConstants.MILLIS_PER_DAY; minSum += millis; MIN_TOTAL_MILLIS_BY_MONTH_ARRAY[i + 1] = minSum; millis = MAX_DAYS_PER_MONTH_ARRAY[i] * (long)DateTimeConstants.MILLIS_PER_DAY; maxSum += millis; MAX_TOTAL_MILLIS_BY_MONTH_ARRAY[i + 1] = maxSum; } } /** * Constructor. */ BasicGJChronology(Chronology base, Object param, int minDaysInFirstWeek) { super(base, param, minDaysInFirstWeek); } //----------------------------------------------------------------------- int getMonthOfYear(long millis, int year) { // Perform a binary search to get the month. To make it go even faster, // compare using ints instead of longs. The number of milliseconds per // year exceeds the limit of a 32-bit int's capacity, so divide by // 1024. No precision is lost (except time of day) since the number of // milliseconds per day contains 1024 as a factor. After the division, // the instant isn't measured in milliseconds, but in units of // (128/125)seconds. int i = (int)((millis - getYearMillis(year)) >> 10); // There are 86400000 milliseconds per day, but divided by 1024 is // 84375. There are 84375 (128/125)seconds per day. return (isLeapYear(year)) ? ((i < 182 * 84375) ? ((i < 91 * 84375) ? ((i < 31 * 84375) ? 1 : (i < 60 * 84375) ? 2 : 3) : ((i < 121 * 84375) ? 4 : (i < 152 * 84375) ? 5 : 6)) : ((i < 274 * 84375) ? ((i < 213 * 84375) ? 7 : (i < 244 * 84375) ? 8 : 9) : ((i < 305 * 84375) ? 10 : (i < 335 * 84375) ? 11 : 12))) : ((i < 181 * 84375) ? ((i < 90 * 84375) ? ((i < 31 * 84375) ? 1 : (i < 59 * 84375) ? 2 : 3) : ((i < 120 * 84375) ? 4 : (i < 151 * 84375) ? 5 : 6)) : ((i < 273 * 84375) ? ((i < 212 * 84375) ? 7 : (i < 243 * 84375) ? 8 : 9) : ((i < 304 * 84375) ? 10 : (i < 334 * 84375) ? 11 : 12))); } //----------------------------------------------------------------------- /** * Gets the number of days in the specified month and year. * * @param year the year * @param month the month * @return the number of days */ int getDaysInYearMonth(int year, int month) { if (isLeapYear(year)) { return MAX_DAYS_PER_MONTH_ARRAY[month - 1]; } else { return MIN_DAYS_PER_MONTH_ARRAY[month - 1]; } } //----------------------------------------------------------------------- int getDaysInMonthMax(int month) { return MAX_DAYS_PER_MONTH_ARRAY[month - 1]; } //----------------------------------------------------------------------- int getDaysInMonthMaxForSet(long instant, int value) { return ((value > 28 || value < 1) ? getDaysInMonthMax(instant) : 28); } //----------------------------------------------------------------------- long getTotalMillisByYearMonth(int year, int month) { if (isLeapYear(year)) { return MAX_TOTAL_MILLIS_BY_MONTH_ARRAY[month - 1]; } else { return MIN_TOTAL_MILLIS_BY_MONTH_ARRAY[month - 1]; } } //----------------------------------------------------------------------- long getYearDifference(long minuendInstant, long subtrahendInstant) { int minuendYear = getYear(minuendInstant); int subtrahendYear = getYear(subtrahendInstant); // Inlined remainder method to avoid duplicate calls to get. long minuendRem = minuendInstant - getYearMillis(minuendYear); long subtrahendRem = subtrahendInstant - getYearMillis(subtrahendYear); // Balance leap year differences on remainders. if (subtrahendRem >= FEB_29) { if (isLeapYear(subtrahendYear)) { if (!isLeapYear(minuendYear)) { subtrahendRem -= DateTimeConstants.MILLIS_PER_DAY; } } else if (minuendRem >= FEB_29 && isLeapYear(minuendYear)) { minuendRem -= DateTimeConstants.MILLIS_PER_DAY; } } int difference = minuendYear - subtrahendYear; if (minuendRem < subtrahendRem) { difference--; } return difference; } //----------------------------------------------------------------------- long setYear(long instant, int year) { int thisYear = getYear(instant); int dayOfYear = getDayOfYear(instant, thisYear); int millisOfDay = getMillisOfDay(instant); if (dayOfYear > (31 + 28)) { // after Feb 28 if (isLeapYear(thisYear)) { // Current date is Feb 29 or later. if (!isLeapYear(year)) { // Moving to a non-leap year, Feb 29 does not exist. dayOfYear--; } } else { // Current date is Mar 01 or later. if (isLeapYear(year)) { // Moving to a leap year, account for Feb 29. dayOfYear++; } } } instant = getYearMonthDayMillis(year, 1, dayOfYear); instant += millisOfDay; return instant; } }





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