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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

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 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

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 */

/**

 * <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>

 *

 * <h2>Fields and Units</h2>

 * <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>

 *

 * <h2>Adjustment and Query</h2>

 * <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>

 *

 * <h2>Weeks</h2>

 * <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>

 *

 * <h2>Package specification</h2>

 * <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 1.8

 */

package java.time.temporal;