| /** |
| * <p> |
| * Access to date and time using fields and units, and date time adjusters. |
| * </p> |
| * <p> |
| * This package expands on the base package to provide additional functionality for |
| * more powerful use cases. Support is included for: |
| * </p> |
| * <ul> |
| * <li>Units of date-time, such as years, months, days and hours</li> |
| * <li>Fields of date-time, such as month-of-year, day-of-week or hour-of-day</li> |
| * <li>Date-time adjustment functions</li> |
| * <li>Different definitions of weeks</li> |
| * </ul> |
| * |
| * <h3>Fields and Units</h3> |
| * <p> |
| * Dates and times are expressed in terms of fields and units. |
| * A unit is used to measure an amount of time, such as years, days or minutes. |
| * All units implement {@link java.time.temporal.TemporalUnit}. |
| * The set of well known units is defined in {@link java.time.temporal.ChronoUnit}, such as {@code DAYS}. |
| * The unit interface is designed to allow application defined units. |
| * </p> |
| * <p> |
| * A field is used to express part of a larger date-time, such as year, month-of-year or second-of-minute. |
| * All fields implement {@link java.time.temporal.TemporalField}. |
| * The set of well known fields are defined in {@link java.time.temporal.ChronoField}, such as {@code HOUR_OF_DAY}. |
| * Additional fields are defined by {@link java.time.temporal.JulianFields}, {@link java.time.temporal.WeekFields} |
| * and {@link java.time.temporal.IsoFields}. |
| * The field interface is designed to allow application defined fields. |
| * </p> |
| * <p> |
| * This package provides tools that allow the units and fields of date and time to be accessed |
| * in a general way most suited for frameworks. |
| * {@link java.time.temporal.Temporal} provides the abstraction for date time types that support fields. |
| * Its methods support getting the value of a field, creating a new date time with the value of |
| * a field modified, and querying for additional information, typically used to extract the offset or time-zone. |
| * </p> |
| * <p> |
| * One use of fields in application code is to retrieve fields for which there is no convenience method. |
| * For example, getting the day-of-month is common enough that there is a method on {@code LocalDate} |
| * called {@code getDayOfMonth()}. However for more unusual fields it is necessary to use the field. |
| * For example, {@code date.get(ChronoField.ALIGNED_WEEK_OF_MONTH)}. |
| * The fields also provide access to the range of valid values. |
| * </p> |
| * |
| * <h3>Adjustment and Query</h3> |
| * <p> |
| * A key part of the date-time problem space is adjusting a date to a new, related value, |
| * such as the "last day of the month", or "next Wednesday". |
| * These are modeled as functions that adjust a base date-time. |
| * The functions implement {@link java.time.temporal.TemporalAdjuster} and operate on {@code Temporal}. |
| * A set of common functions are provided in {@link java.time.temporal.TemporalAdjusters}. |
| * For example, to find the first occurrence of a day-of-week after a given date, use |
| * {@link java.time.temporal.TemporalAdjusters#next(DayOfWeek)}, such as |
| * {@code date.with(next(MONDAY))}. |
| * Applications can also define adjusters by implementing {@link java.time.temporal.TemporalAdjuster}. |
| * </p> |
| * <p> |
| * The {@link java.time.temporal.TemporalAmount} interface models amounts of relative time. |
| * </p> |
| * <p> |
| * In addition to adjusting a date-time, an interface is provided to enable querying via |
| * {@link java.time.temporal.TemporalQuery}. |
| * The most common implementations of the query interface are method references. |
| * The {@code from(TemporalAccessor)} methods on major classes can all be used, such as |
| * {@code LocalDate::from} or {@code Month::from}. |
| * Further implementations are provided in {@link java.time.temporal.TemporalQueries} as static methods. |
| * Applications can also define queries by implementing {@link java.time.temporal.TemporalQuery}. |
| * </p> |
| * |
| * <h3>Weeks</h3> |
| * <p> |
| * Different locales have different definitions of the week. |
| * For example, in Europe the week typically starts on a Monday, while in the US it starts on a Sunday. |
| * The {@link java.time.temporal.WeekFields} class models this distinction. |
| * </p> |
| * <p> |
| * The ISO calendar system defines an additional week-based division of years. |
| * This defines a year based on whole Monday to Monday weeks. |
| * This is modeled in {@link java.time.temporal.IsoFields}. |
| * </p> |
| * |
| * <h3>Package specification</h3> |
| * <p> |
| * Unless otherwise noted, passing a null argument to a constructor or method in any class or interface |
| * in this package will cause a {@link java.lang.NullPointerException NullPointerException} to be thrown. |
| * The Javadoc "@param" definition is used to summarise the null-behavior. |
| * The "@throws {@link java.lang.NullPointerException}" is not explicitly documented in each method. |
| * </p> |
| * <p> |
| * All calculations should check for numeric overflow and throw either an {@link java.lang.ArithmeticException} |
| * or a {@link java.time.DateTimeException}. |
| * </p> |
| * @since JDK1.8 |
| */ |
| |
| package java.time.temporal; |
