1 /* 2 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file: 31 * 32 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos 33 * 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions are met: 38 * 39 * * Redistributions of source code must retain the above copyright notice, 40 * this list of conditions and the following disclaimer. 41 * 42 * * Redistributions in binary form must reproduce the above copyright notice, 43 * this list of conditions and the following disclaimer in the documentation 44 * and/or other materials provided with the distribution. 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 application 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 application 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.TemporalAdjusters}. 116 * For example, to find the first occurrence of a day-of-week after a given date, use 117 * {@link java.time.temporal.TemporalAdjusters#next(DayOfWeek)}, such as 118 * {@code date.with(next(MONDAY))}. 119 * Applications can also define adjusters by implementing {@link java.time.temporal.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 via 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.TemporalQueries} as static methods. 131 * Applications can also define queries by implementing {@link java.time.temporal.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; 160
