| 1 | /* |
| 2 | * Copyright 2001-2005 Stephen Colebourne |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.joda.time.chrono; |
| 17 | |
| 18 | import org.joda.time.Chronology; |
| 19 | import org.joda.time.DateTimeConstants; |
| 20 | |
| 21 | /** |
| 22 | * Abstract implementation of a calendar system based around fixed length months. |
| 23 | * <p> |
| 24 | * As the month length is fixed various calculations can be optimised. |
| 25 | * This implementation assumes any additional days after twelve |
| 26 | * months fall into a thirteenth month. |
| 27 | * <p> |
| 28 | * BasicFixedMonthChronology is thread-safe and immutable, and all |
| 29 | * subclasses must be as well. |
| 30 | * |
| 31 | * @author Brian S O'Neill |
| 32 | * @author Stephen Colebourne |
| 33 | * @since 1.2, refactored from CopticChronology |
| 34 | */ |
| 35 | abstract class BasicFixedMonthChronology extends BasicChronology { |
| 36 | |
| 37 | /** Serialization lock */ |
| 38 | private static final long serialVersionUID = 261387371998L; |
| 39 | |
| 40 | /** The length of the month. */ |
| 41 | static final int MONTH_LENGTH = 30; |
| 42 | |
| 43 | /** The typical millis per year. */ |
| 44 | static final long MILLIS_PER_YEAR = |
| 45 | (long) (365.25 * DateTimeConstants.MILLIS_PER_DAY); |
| 46 | |
| 47 | /** The length of the month in millis. */ |
| 48 | static final long MILLIS_PER_MONTH = ((long) MONTH_LENGTH) * DateTimeConstants.MILLIS_PER_DAY; |
| 49 | |
| 50 | //----------------------------------------------------------------------- |
| 51 | /** |
| 52 | * Restricted constructor. |
| 53 | * |
| 54 | * @param base the base chronology |
| 55 | * @param param the init parameter |
| 56 | * @param minDaysInFirstWeek the minimum days in the first week |
| 57 | */ |
| 58 | BasicFixedMonthChronology(Chronology base, Object param, int minDaysInFirstWeek) { |
| 59 | super(base, param, minDaysInFirstWeek); |
| 60 | } |
| 61 | |
| 62 | //----------------------------------------------------------------------- |
| 63 | long setYear(long instant, int year) { |
| 64 | // optimsed implementation of set, due to fixed months |
| 65 | int thisYear = getYear(instant); |
| 66 | int dayOfYear = getDayOfYear(instant, thisYear); |
| 67 | int millisOfDay = getMillisOfDay(instant); |
| 68 | |
| 69 | if (dayOfYear > 365) { |
| 70 | // Current year is leap, and day is leap. |
| 71 | if (!isLeapYear(year)) { |
| 72 | // Moving to a non-leap year, leap day doesn't exist. |
| 73 | dayOfYear--; |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | instant = getYearMonthDayMillis(year, 1, dayOfYear); |
| 78 | instant += millisOfDay; |
| 79 | return instant; |
| 80 | } |
| 81 | |
| 82 | //----------------------------------------------------------------------- |
| 83 | long getYearDifference(long minuendInstant, long subtrahendInstant) { |
| 84 | // optimsed implementation of getDifference, due to fixed months |
| 85 | int minuendYear = getYear(minuendInstant); |
| 86 | int subtrahendYear = getYear(subtrahendInstant); |
| 87 | |
| 88 | // Inlined remainder method to avoid duplicate calls to get. |
| 89 | long minuendRem = minuendInstant - getYearMillis(minuendYear); |
| 90 | long subtrahendRem = subtrahendInstant - getYearMillis(subtrahendYear); |
| 91 | |
| 92 | int difference = minuendYear - subtrahendYear; |
| 93 | if (minuendRem < subtrahendRem) { |
| 94 | difference--; |
| 95 | } |
| 96 | return difference; |
| 97 | } |
| 98 | |
| 99 | //----------------------------------------------------------------------- |
| 100 | long getTotalMillisByYearMonth(int year, int month) { |
| 101 | return ((month - 1) * MILLIS_PER_MONTH); |
| 102 | } |
| 103 | |
| 104 | //----------------------------------------------------------------------- |
| 105 | int getDayOfMonth(long millis) { |
| 106 | // optimised for fixed months |
| 107 | return (getDayOfYear(millis) - 1) % MONTH_LENGTH + 1; |
| 108 | } |
| 109 | |
| 110 | //----------------------------------------------------------------------- |
| 111 | boolean isLeapYear(int year) { |
| 112 | return (year & 3) == 3; |
| 113 | } |
| 114 | |
| 115 | //----------------------------------------------------------------------- |
| 116 | int getDaysInYearMonth(int year, int month) { |
| 117 | return (month != 13) ? MONTH_LENGTH : (isLeapYear(year) ? 6 : 5); |
| 118 | } |
| 119 | |
| 120 | //----------------------------------------------------------------------- |
| 121 | int getDaysInMonthMax() { |
| 122 | return MONTH_LENGTH; |
| 123 | } |
| 124 | |
| 125 | //----------------------------------------------------------------------- |
| 126 | int getDaysInMonthMax(int month) { |
| 127 | return (month != 13 ? MONTH_LENGTH : 6); |
| 128 | } |
| 129 | |
| 130 | //----------------------------------------------------------------------- |
| 131 | int getMonthOfYear(long millis) { |
| 132 | return (getDayOfYear(millis) - 1) / MONTH_LENGTH + 1; |
| 133 | } |
| 134 | |
| 135 | //----------------------------------------------------------------------- |
| 136 | int getMonthOfYear(long millis, int year) { |
| 137 | long monthZeroBased = (millis - getYearMillis(year)) / MILLIS_PER_MONTH; |
| 138 | return ((int) monthZeroBased) + 1; |
| 139 | } |
| 140 | |
| 141 | //----------------------------------------------------------------------- |
| 142 | int getMaxMonth() { |
| 143 | return 13; |
| 144 | } |
| 145 | |
| 146 | //----------------------------------------------------------------------- |
| 147 | long getAverageMillisPerYear() { |
| 148 | return MILLIS_PER_YEAR; |
| 149 | } |
| 150 | |
| 151 | //----------------------------------------------------------------------- |
| 152 | long getAverageMillisPerYearDividedByTwo() { |
| 153 | return MILLIS_PER_YEAR / 2; |
| 154 | } |
| 155 | |
| 156 | //----------------------------------------------------------------------- |
| 157 | long getAverageMillisPerMonth() { |
| 158 | return MILLIS_PER_MONTH; |
| 159 | } |
| 160 | |
| 161 | } |