author | rriggs |
Thu, 26 Sep 2013 23:05:29 -0700 | |
changeset 20793 | 5acd4b8d70a1 |
parent 20523 | aee7c8a56c75 |
child 24256 | da9a41004459 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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||
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/* |
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* This file is available under and governed by the GNU General Public |
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* License version 2 only, as published by the Free Software Foundation. |
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* However, the following notice accompanied the original version of this |
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* file: |
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* |
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* Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos |
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* |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions are met: |
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* |
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* * Redistributions of source code must retain the above copyright notice, |
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* this list of conditions and the following disclaimer. |
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* |
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* * Redistributions in binary form must reproduce the above copyright notice, |
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* this list of conditions and the following disclaimer in the documentation |
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* and/or other materials provided with the distribution. |
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* |
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* * Neither the name of JSR-310 nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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package java.time.temporal; |
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import java.time.DateTimeException; |
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import java.time.chrono.Chronology; |
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import java.time.format.ResolverStyle; |
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import java.util.Locale; |
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import java.util.Map; |
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import java.util.Objects; |
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/** |
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* A field of date-time, such as month-of-year or hour-of-minute. |
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* <p> |
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* Date and time is expressed using fields which partition the time-line into something |
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* meaningful for humans. Implementations of this interface represent those fields. |
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* <p> |
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* The most commonly used units are defined in {@link ChronoField}. |
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* Further fields are supplied in {@link IsoFields}, {@link WeekFields} and {@link JulianFields}. |
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* Fields can also be written by application code by implementing this interface. |
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* <p> |
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* The field works using double dispatch. Client code calls methods on a date-time like |
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* {@code LocalDateTime} which check if the field is a {@code ChronoField}. |
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* If it is, then the date-time must handle it. |
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* Otherwise, the method call is re-dispatched to the matching method in this interface. |
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* |
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* @implSpec |
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* This interface must be implemented with care to ensure other classes operate correctly. |
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* All implementations that can be instantiated must be final, immutable and thread-safe. |
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* Implementations should be {@code Serializable} where possible. |
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* An enum is as effective implementation choice. |
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* |
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* @since 1.8 |
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*/ |
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public interface TemporalField { |
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/** |
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* Gets the display name for the field in the requested locale. |
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* <p> |
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* If there is no display name for the locale then a suitable default must be returned. |
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* <p> |
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* The default implementation must check the locale is not null |
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* and return {@code toString()}. |
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* |
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* @param locale the locale to use, not null |
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* @return the display name for the locale or a suitable default, not null |
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*/ |
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default String getDisplayName(Locale locale) { |
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Objects.requireNonNull(locale, "locale"); |
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return toString(); |
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} |
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/** |
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* Gets the unit that the field is measured in. |
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* <p> |
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* The unit of the field is the period that varies within the range. |
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* For example, in the field 'MonthOfYear', the unit is 'Months'. |
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* See also {@link #getRangeUnit()}. |
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* |
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* @return the period unit defining the base unit of the field, not null |
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*/ |
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TemporalUnit getBaseUnit(); |
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/** |
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* Gets the range that the field is bound by. |
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* <p> |
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* The range of the field is the period that the field varies within. |
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* For example, in the field 'MonthOfYear', the range is 'Years'. |
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* See also {@link #getBaseUnit()}. |
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* <p> |
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* The range is never null. For example, the 'Year' field is shorthand for |
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* 'YearOfForever'. It therefore has a unit of 'Years' and a range of 'Forever'. |
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* |
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* @return the period unit defining the range of the field, not null |
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*/ |
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TemporalUnit getRangeUnit(); |
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/** |
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* Gets the range of valid values for the field. |
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* <p> |
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* All fields can be expressed as a {@code long} integer. |
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* This method returns an object that describes the valid range for that value. |
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* This method is generally only applicable to the ISO-8601 calendar system. |
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* <p> |
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* Note that the result only describes the minimum and maximum valid values |
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* and it is important not to read too much into them. For example, there |
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* could be values within the range that are invalid for the field. |
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* |
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* @return the range of valid values for the field, not null |
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*/ |
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ValueRange range(); |
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//----------------------------------------------------------------------- |
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/** |
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* Checks if this field represents a component of a date. |
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* <p> |
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* A field is date-based if it can be derived from |
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* {@link ChronoField#EPOCH_DAY EPOCH_DAY}. |
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* Note that it is valid for both {@code isDateBased()} and {@code isTimeBased()} |
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* to return false, such as when representing a field like minute-of-week. |
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* |
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* @return true if this field is a component of a date |
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*/ |
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boolean isDateBased(); |
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/** |
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* Checks if this field represents a component of a time. |
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* <p> |
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* A field is time-based if it can be derived from |
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* {@link ChronoField#NANO_OF_DAY NANO_OF_DAY}. |
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* Note that it is valid for both {@code isDateBased()} and {@code isTimeBased()} |
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* to return false, such as when representing a field like minute-of-week. |
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* |
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* @return true if this field is a component of a time |
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*/ |
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boolean isTimeBased(); |
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//----------------------------------------------------------------------- |
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/** |
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* Checks if this field is supported by the temporal object. |
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* <p> |
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* This determines whether the temporal accessor supports this field. |
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* If this returns false, the the temporal cannot be queried for this field. |
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* <p> |
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* There are two equivalent ways of using this method. |
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* The first is to invoke this method directly. |
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* The second is to use {@link TemporalAccessor#isSupported(TemporalField)}: |
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* <pre> |
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* // these two lines are equivalent, but the second approach is recommended |
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* temporal = thisField.isSupportedBy(temporal); |
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* temporal = temporal.isSupported(thisField); |
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* </pre> |
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* It is recommended to use the second approach, {@code isSupported(TemporalField)}, |
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* as it is a lot clearer to read in code. |
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* <p> |
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* Implementations should determine whether they are supported using the fields |
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* available in {@link ChronoField}. |
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* |
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* @param temporal the temporal object to query, not null |
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* @return true if the date-time can be queried for this field, false if not |
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*/ |
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boolean isSupportedBy(TemporalAccessor temporal); |
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/** |
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* Get the range of valid values for this field using the temporal object to |
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* refine the result. |
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* <p> |
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* This uses the temporal object to find the range of valid values for the field. |
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* This is similar to {@link #range()}, however this method refines the result |
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* using the temporal. For example, if the field is {@code DAY_OF_MONTH} the |
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* {@code range} method is not accurate as there are four possible month lengths, |
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* 28, 29, 30 and 31 days. Using this method with a date allows the range to be |
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* accurate, returning just one of those four options. |
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* <p> |
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* There are two equivalent ways of using this method. |
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* The first is to invoke this method directly. |
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* The second is to use {@link TemporalAccessor#range(TemporalField)}: |
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* <pre> |
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* // these two lines are equivalent, but the second approach is recommended |
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* temporal = thisField.rangeRefinedBy(temporal); |
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* temporal = temporal.range(thisField); |
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* </pre> |
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* It is recommended to use the second approach, {@code range(TemporalField)}, |
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* as it is a lot clearer to read in code. |
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* <p> |
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* Implementations should perform any queries or calculations using the fields |
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* available in {@link ChronoField}. |
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* If the field is not supported an {@code UnsupportedTemporalTypeException} must be thrown. |
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* |
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* @param temporal the temporal object used to refine the result, not null |
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* @return the range of valid values for this field, not null |
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* @throws DateTimeException if the range for the field cannot be obtained |
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* @throws UnsupportedTemporalTypeException if the field is not supported by the temporal |
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*/ |
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ValueRange rangeRefinedBy(TemporalAccessor temporal); |
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/** |
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* Gets the value of this field from the specified temporal object. |
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* <p> |
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* This queries the temporal object for the value of this field. |
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* <p> |
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* There are two equivalent ways of using this method. |
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* The first is to invoke this method directly. |
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* The second is to use {@link TemporalAccessor#getLong(TemporalField)} |
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* (or {@link TemporalAccessor#get(TemporalField)}): |
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* <pre> |
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* // these two lines are equivalent, but the second approach is recommended |
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* temporal = thisField.getFrom(temporal); |
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* temporal = temporal.getLong(thisField); |
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* </pre> |
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* It is recommended to use the second approach, {@code getLong(TemporalField)}, |
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* as it is a lot clearer to read in code. |
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* <p> |
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* Implementations should perform any queries or calculations using the fields |
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* available in {@link ChronoField}. |
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* If the field is not supported an {@code UnsupportedTemporalTypeException} must be thrown. |
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* |
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* @param temporal the temporal object to query, not null |
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* @return the value of this field, not null |
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* @throws DateTimeException if a value for the field cannot be obtained |
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* @throws UnsupportedTemporalTypeException if the field is not supported by the temporal |
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* @throws ArithmeticException if numeric overflow occurs |
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*/ |
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long getFrom(TemporalAccessor temporal); |
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/** |
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* Returns a copy of the specified temporal object with the value of this field set. |
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* <p> |
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* This returns a new temporal object based on the specified one with the value for |
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* this field changed. For example, on a {@code LocalDate}, this could be used to |
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* set the year, month or day-of-month. |
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* The returned object has the same observable type as the specified object. |
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* <p> |
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* In some cases, changing a field is not fully defined. For example, if the target object is |
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* a date representing the 31st January, then changing the month to February would be unclear. |
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* In cases like this, the implementation is responsible for resolving the result. |
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* Typically it will choose the previous valid date, which would be the last valid |
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* day of February in this example. |
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* <p> |
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* There are two equivalent ways of using this method. |
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* The first is to invoke this method directly. |
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* The second is to use {@link Temporal#with(TemporalField, long)}: |
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* <pre> |
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* // these two lines are equivalent, but the second approach is recommended |
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* temporal = thisField.adjustInto(temporal); |
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* temporal = temporal.with(thisField); |
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* </pre> |
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* It is recommended to use the second approach, {@code with(TemporalField)}, |
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* as it is a lot clearer to read in code. |
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* <p> |
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* Implementations should perform any queries or calculations using the fields |
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* available in {@link ChronoField}. |
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* If the field is not supported an {@code UnsupportedTemporalTypeException} must be thrown. |
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* <p> |
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* Implementations must not alter the specified temporal object. |
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* Instead, an adjusted copy of the original must be returned. |
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* This provides equivalent, safe behavior for immutable and mutable implementations. |
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* |
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* @param <R> the type of the Temporal object |
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* @param temporal the temporal object to adjust, not null |
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* @param newValue the new value of the field |
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* @return the adjusted temporal object, not null |
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* @throws DateTimeException if the field cannot be set |
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* @throws UnsupportedTemporalTypeException if the field is not supported by the temporal |
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* @throws ArithmeticException if numeric overflow occurs |
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*/ |
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<R extends Temporal> R adjustInto(R temporal, long newValue); |
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/** |
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* Resolves this field to provide a simpler alternative or a date. |
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* <p> |
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* This method is invoked during the resolve phase of parsing. |
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* It is designed to allow application defined fields to be simplified into |
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* more standard fields, such as those on {@code ChronoField}, or into a date. |
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* <p> |
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* Applications should not normally invoke this method directly. |
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* |
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* @implSpec |
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* If an implementation represents a field that can be simplified, or |
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* combined with others, then this method must be implemented. |
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* <p> |
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* The specified map contains the current state of the parse. |
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* The map is mutable and must be mutated to resolve the field and |
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* any related fields. This method will only be invoked during parsing |
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* if the map contains this field, and implementations should therefore |
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* assume this field is present. |
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* <p> |
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* Resolving a field will consist of looking at the value of this field, |
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* and potentially other fields, and either updating the map with a |
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* simpler value, such as a {@code ChronoField}, or returning a |
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* complete {@code ChronoLocalDate}. If a resolve is successful, |
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* the code must remove all the fields that were resolved from the map, |
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* including this field. |
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* <p> |
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* For example, the {@code IsoFields} class contains the quarter-of-year |
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* and day-of-quarter fields. The implementation of this method in that class |
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* resolves the two fields plus the {@link ChronoField#YEAR YEAR} into a |
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* complete {@code LocalDate}. The resolve method will remove all three |
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* fields from the map before returning the {@code LocalDate}. |
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* <p> |
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* A partially complete temporal is used to allow the chronology and zone |
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* to be queried. In general, only the chronology will be needed. |
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* Querying items other than the zone or chronology is undefined and |
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* must not be relied on. |
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* The behavior of other methods such as {@code get}, {@code getLong}, |
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* {@code range} and {@code isSupported} is unpredictable and the results undefined. |
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* <p> |
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* If resolution should be possible, but the data is invalid, the resolver |
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* style should be used to determine an appropriate level of leniency, which |
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* may require throwing a {@code DateTimeException} or {@code ArithmeticException}. |
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* If no resolution is possible, the resolve method must return null. |
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* <p> |
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* When resolving time fields, the map will be altered and null returned. |
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* When resolving date fields, the date is normally returned from the method, |
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* with the map altered to remove the resolved fields. However, it would also |
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* be acceptable for the date fields to be resolved into other {@code ChronoField} |
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* instances that can produce a date, such as {@code EPOCH_DAY}. |
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* <p> |
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* Not all {@code TemporalAccessor} implementations are accepted as return values. |
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* Implementations that call this method must accept {@code ChronoLocalDate}, |
360 |
* {@code ChronoLocalDateTime}, {@code ChronoZonedDateTime} and {@code LocalTime}. |
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* <p> |
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* The default implementation must return null. |
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* |
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* @param fieldValues the map of fields to values, which can be updated, not null |
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* @param partialTemporal the partially complete temporal to query for zone and |
366 |
* chronology; querying for other things is undefined and not recommended, not null |
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* @param resolverStyle the requested type of resolve, not null |
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* @return the resolved temporal object; null if resolving only |
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* changed the map, or no resolve occurred |
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* @throws ArithmeticException if numeric overflow occurs |
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* @throws DateTimeException if resolving results in an error. This must not be thrown |
372 |
* by querying a field on the temporal without first checking if it is supported |
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*/ |
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|
374 |
default TemporalAccessor resolve( |
20793 | 375 |
Map<TemporalField, Long> fieldValues, |
376 |
TemporalAccessor partialTemporal, |
|
377 |
ResolverStyle resolverStyle) { |
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return null; |
379 |
} |
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/** |
382 |
* Gets a descriptive name for the field. |
|
383 |
* <p> |
|
384 |
* The should be of the format 'BaseOfRange', such as 'MonthOfYear', |
|
385 |
* unless the field has a range of {@code FOREVER}, when only |
|
386 |
* the base unit is mentioned, such as 'Year' or 'Era'. |
|
387 |
* |
|
388 |
* @return the name of the field, not null |
|
389 |
*/ |
|
390 |
@Override |
|
391 |
String toString(); |
|
392 |
||
393 |
||
15289 | 394 |
} |