45 * 46 * * Neither the name of JSR-310 nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 63 /** 64 * <p> 65 * Access to date and time using fields and units, additional value type classes and 66 * base support for calendar systems other than the default ISO. 67 * </p> 68 * <p> 69 * This package expands on the base package to provide additional functionality for 70 * more powerful use cases. Support is included for: 71 * </p> 72 * <ul> 73 * <li>Units of date-time, such as years, months, days and hours</li> 74 * <li>Fields of date-time, such as month-of-year, day-of-week or hour-of-day</li> 75 * <li>Date-time adjustment functions</li> 76 * <li>Different definitions of weeks</li> 77 * <li>Alternate calendar systems</li> 78 * <li>Additional value types</li> 79 * </ul> 80 * 81 * <h3>Fields and Units</h3> 82 * <p> 83 * Dates and times are expressed in terms of fields and units. 84 * A unit is used to measure an amount of time, such as years, days or minutes. 85 * All units implement {@link java.time.temporal.TemporalUnit}. 86 * The set of well known units is defined in {@link java.time.temporal.ChronoUnit}, such as {@code DAYS}. 87 * The unit interface is designed to allow applications defined units. 88 * </p> 89 * <p> 90 * A field is used to express part of a larger date-time, such as year, month-of-year or second-of-minute. 91 * All fields implement {@link java.time.temporal.TemporalField}. 92 * The set of well known fields are defined in {@link java.time.temporal.ChronoField}, such as {@code HOUR_OF_DAY}. 93 * Additional fields are defined by {@link java.time.temporal.JulianFields}, {@link java.time.temporal.WeekFields} 94 * and {@link java.time.temporal.ISOFields}. 95 * The field interface is designed to allow applications defined fields. 96 * </p> 97 * <p> 98 * This package provides tools that allow the units and fields of date and time to be accessed 99 * in a general way most suited for frameworks. 100 * {@link java.time.temporal.Temporal} provides the abstraction for date time types that support fields. 101 * Its methods support getting the value of a field, creating a new date time with the value of 102 * a field modified, and querying for additional information, typically used to extract the offset or time-zone. 103 * </p> 104 * <p> 105 * One use of fields in application code is to retrieve fields for which there is no convenience method. 106 * For example, getting the day-of-month is common enough that there is a method on {@code LocalDate} 107 * called {@code getDayOfMonth()}. However for more unusual fields it is necessary to use the field. 108 * For example, {@code date.get(ChronoField.ALIGNED_WEEK_OF_MONTH)}. 109 * The fields also provide access to the range of valid values. 110 * </p> 111 * 112 * <h3>Adjustment and Query</h3> 113 * <p> 114 * A key part of the date-time problem space is adjusting a date to a new, related value, 115 * such as the "last day of the month", or "next Wednesday". 116 * These are modeled as functions that adjust a base date-time. 117 * The functions implement {@link java.time.temporal.TemporalAdjuster} and operate on {@code Temporal}. 118 * A set of common functions are provided in {@link java.time.temporal.Adjusters}. 119 * For example, to find the first occurrence of a day-of-week after a given date, use 120 * {@link java.time.temporal.Adjusters#next(DayOfWeek)}, such as 121 * {@code date.with(next(MONDAY))}. 122 * Applications can also define adjusters by implementing {@code TemporalAdjuster}. 123 * </p> 124 * <p> 125 * There are additional interfaces to model addition to and subtraction from a date-time. 126 * These are {@link java.time.temporal.TemporalAdder} and {@link java.time.temporal.TemporalSubtractor}. 127 * </p> 128 * <p> 129 * In addition to adjusting a date-time, an interface is provided to enable querying - 130 * {@link java.time.temporal.TemporalQuery}. 131 * The most common implementations of the query interface are method references. 132 * The {@code from(TemporalAccessor)} methods on major classes can all be used, such as 133 * {@code LocalDate::from} or {@code Month::from}. 134 * Further implementations are provided in {@link java.time.temporal.Queries}. 135 * Applications can also define queries by implementing {@code TemporalQuery}. 136 * </p> 137 * 138 * <h3>Weeks</h3> 139 * <p> 140 * Different locales have different definitions of the week. 141 * For example, in Europe the week typically starts on a Monday, while in the US it starts on a Sunday. 142 * The {@link java.time.temporal.WeekFields} class models this distinction. 143 * </p> 144 * <p> 145 * The ISO calendar system defines an additional week-based division of years. 146 * This defines a year based on whole Monday to Monday weeks. 147 * This is modeled in {@link java.time.temporal.ISOFields}. 148 * </p> 149 * 150 * <h3>Alternate calendar systems</h3> 151 * <p> 152 * The main API is based around the calendar system defined in ISO-8601. 153 * However, there are other calendar systems, and this package provides basic support for them. 154 * The alternate calendars are provided in the {@code java.time.calendar} package. 155 * </p> 156 * <p> 157 * A calendar system is defined by the {@link java.time.temporal.Chrono} interface, 158 * while a date in a calendar system is defined by the {@link java.time.temporal.ChronoLocalDate} interface. 159 * </p> 160 * <p> 161 * It is intended that applications use the main API whenever possible, including code to read and write 162 * from a persistent data store, such as a database, and to send dates and times across a network. 163 * The "chrono" classes are then used at the user interface level to deal with localized input/output. 164 * </p> 165 * <p> 166 * Using non-ISO calendar systems in an application introduces significant extra complexity. 167 * Ensure that the warnings and recommendations in {@code ChronoLocalDate} have been read before 168 * working with the "chrono" interfaces. 169 * </p> 170 * <p> 171 * This example creates and uses a date in a non-ISO calendar system. 172 * </p> 173 * <pre> 174 * // Print the Thai Buddhist date 175 * ChronoLocalDate<ThaiBuddhistChrono> now1 = ThaiBuddhistChrono.INSTANCE.dateNow(); 176 * int day = now1.get(ChronoField.DAY_OF_MONTH); 177 * int dow = now1.get(ChronoField.DAY_OF_WEEK); 178 * int month = now1.get(ChronoField.MONTH_OF_YEAR); 179 * int year = now1.get(ChronoField.YEAR); 180 * System.out.printf(" Today is %s %s %d-%s-%d%n", now1.getChrono().getId(), 181 * dow, day, month, year); 182 * 183 * // Enumerate the list of available calendars and print today for each 184 * Set<Chrono<?>> chronos = Chrono.getAvailableChronologies(); 185 * for (Chrono<?> chrono : chronos) { 186 * ChronoLocalDate<?> date = chrono.dateNow(); 187 * System.out.printf(" %20s: %s%n", chrono.getId(), date.toString()); 188 * } 189 * 190 * // Print today's date and the last day of the year for the Thai Buddhist Calendar. 191 * ChronoLocalDate<ThaiBuddhistChrono> first = now1 192 * .with(ChronoField.DAY_OF_MONTH, 1) 193 * .with(ChronoField.MONTH_OF_YEAR, 1); 194 * ChronoLocalDate<ThaiBuddhistChrono> last = first 195 * .plus(1, ChronoUnit.YEARS) 196 * .minus(1, ChronoUnit.DAYS); 197 * System.out.printf(" %s: 1st of year: %s; end of year: %s%n", last.getChrono().getId(), 198 * first, last); 199 * </pre> 200 * 201 * <h3>Package specification</h3> 202 * <p> 203 * Unless otherwise noted, passing a null argument to a constructor or method in any class or interface 204 * in this package will cause a {@link java.lang.NullPointerException NullPointerException} to be thrown. 205 * The Javadoc "@param" definition is used to summarise the null-behavior. 206 * The "@throws {@link java.lang.NullPointerException}" is not explicitly documented in each method. 207 * </p> 208 * <p> 209 * All calculations should check for numeric overflow and throw either an {@link java.lang.ArithmeticException} 210 * or a {@link java.time.DateTimeException}. 211 * </p> 212 * @since JDK1.8 213 */ 214 package java.time.temporal; | 45 * 46 * * Neither the name of JSR-310 nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 63 /** 64 * <p> 65 * Access to date and time using fields and units, and date time adjusters. 66 * </p> 67 * <p> 68 * This package expands on the base package to provide additional functionality for 69 * more powerful use cases. Support is included for: 70 * </p> 71 * <ul> 72 * <li>Units of date-time, such as years, months, days and hours</li> 73 * <li>Fields of date-time, such as month-of-year, day-of-week or hour-of-day</li> 74 * <li>Date-time adjustment functions</li> 75 * <li>Different definitions of weeks</li> 76 * </ul> 77 * 78 * <h3>Fields and Units</h3> 79 * <p> 80 * Dates and times are expressed in terms of fields and units. 81 * A unit is used to measure an amount of time, such as years, days or minutes. 82 * All units implement {@link java.time.temporal.TemporalUnit}. 83 * The set of well known units is defined in {@link java.time.temporal.ChronoUnit}, such as {@code DAYS}. 84 * The unit interface is designed to allow applications defined units. 85 * </p> 86 * <p> 87 * A field is used to express part of a larger date-time, such as year, month-of-year or second-of-minute. 88 * All fields implement {@link java.time.temporal.TemporalField}. 89 * The set of well known fields are defined in {@link java.time.temporal.ChronoField}, such as {@code HOUR_OF_DAY}. 90 * Additional fields are defined by {@link java.time.temporal.JulianFields}, {@link java.time.temporal.WeekFields} 91 * and {@link java.time.temporal.IsoFields}. 92 * The field interface is designed to allow applications defined fields. 93 * </p> 94 * <p> 95 * This package provides tools that allow the units and fields of date and time to be accessed 96 * in a general way most suited for frameworks. 97 * {@link java.time.temporal.Temporal} provides the abstraction for date time types that support fields. 98 * Its methods support getting the value of a field, creating a new date time with the value of 99 * a field modified, and querying for additional information, typically used to extract the offset or time-zone. 100 * </p> 101 * <p> 102 * One use of fields in application code is to retrieve fields for which there is no convenience method. 103 * For example, getting the day-of-month is common enough that there is a method on {@code LocalDate} 104 * called {@code getDayOfMonth()}. However for more unusual fields it is necessary to use the field. 105 * For example, {@code date.get(ChronoField.ALIGNED_WEEK_OF_MONTH)}. 106 * The fields also provide access to the range of valid values. 107 * </p> 108 * 109 * <h3>Adjustment and Query</h3> 110 * <p> 111 * A key part of the date-time problem space is adjusting a date to a new, related value, 112 * such as the "last day of the month", or "next Wednesday". 113 * These are modeled as functions that adjust a base date-time. 114 * The functions implement {@link java.time.temporal.TemporalAdjuster} and operate on {@code Temporal}. 115 * A set of common functions are provided in {@link java.time.temporal.Adjusters}. 116 * For example, to find the first occurrence of a day-of-week after a given date, use 117 * {@link java.time.temporal.Adjusters#next(DayOfWeek)}, such as 118 * {@code date.with(next(MONDAY))}. 119 * Applications can also define adjusters by implementing {@code TemporalAdjuster}. 120 * </p> 121 * <p> 122 * The {@link java.time.temporal.TemporalAmount} interface models amounts of relative time. 123 * </p> 124 * <p> 125 * In addition to adjusting a date-time, an interface is provided to enable querying - 126 * {@link java.time.temporal.TemporalQuery}. 127 * The most common implementations of the query interface are method references. 128 * The {@code from(TemporalAccessor)} methods on major classes can all be used, such as 129 * {@code LocalDate::from} or {@code Month::from}. 130 * Further implementations are provided in {@link java.time.temporal.Queries}. 131 * Applications can also define queries by implementing {@code TemporalQuery}. 132 * </p> 133 * 134 * <h3>Weeks</h3> 135 * <p> 136 * Different locales have different definitions of the week. 137 * For example, in Europe the week typically starts on a Monday, while in the US it starts on a Sunday. 138 * The {@link java.time.temporal.WeekFields} class models this distinction. 139 * </p> 140 * <p> 141 * The ISO calendar system defines an additional week-based division of years. 142 * This defines a year based on whole Monday to Monday weeks. 143 * This is modeled in {@link java.time.temporal.IsoFields}. 144 * </p> 145 * 146 * <h3>Package specification</h3> 147 * <p> 148 * Unless otherwise noted, passing a null argument to a constructor or method in any class or interface 149 * in this package will cause a {@link java.lang.NullPointerException NullPointerException} to be thrown. 150 * The Javadoc "@param" definition is used to summarise the null-behavior. 151 * The "@throws {@link java.lang.NullPointerException}" is not explicitly documented in each method. 152 * </p> 153 * <p> 154 * All calculations should check for numeric overflow and throw either an {@link java.lang.ArithmeticException} 155 * or a {@link java.time.DateTimeException}. 156 * </p> 157 * @since JDK1.8 158 */ 159 package java.time.temporal; |