author | sherman |
Thu, 14 Aug 2014 15:54:04 -0700 | |
changeset 25986 | 12bcf9a5994f |
parent 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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* 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.util.Objects; |
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/** |
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* Framework-level interface defining read-only access to a temporal object, |
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* such as a date, time, offset or some combination of these. |
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* <p> |
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* This is the base interface type for date, time and offset objects. |
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* It is implemented by those classes that can provide information |
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* as {@linkplain TemporalField fields} or {@linkplain TemporalQuery queries}. |
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* <p> |
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* Most date and time information can be represented as a number. |
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* These are modeled using {@code TemporalField} with the number held using |
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* a {@code long} to handle large values. Year, month and day-of-month are |
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* simple examples of fields, but they also include instant and offsets. |
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* See {@link ChronoField} for the standard set of fields. |
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* <p> |
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* Two pieces of date/time information cannot be represented by numbers, |
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* the {@linkplain java.time.chrono.Chronology chronology} and the |
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* {@linkplain java.time.ZoneId time-zone}. |
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* These can be accessed via {@linkplain #query(TemporalQuery) queries} using |
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* the static methods defined on {@link TemporalQuery}. |
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* <p> |
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* A sub-interface, {@link Temporal}, extends this definition to one that also |
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* supports adjustment and manipulation on more complete temporal objects. |
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* <p> |
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* This interface is a framework-level interface that should not be widely |
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* used in application code. Instead, applications should create and pass |
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* around instances of concrete types, such as {@code LocalDate}. |
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* There are many reasons for this, part of which is that implementations |
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* of this interface may be in calendar systems other than ISO. |
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* See {@link java.time.chrono.ChronoLocalDate} for a fuller discussion of the issues. |
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* |
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* @implSpec |
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* This interface places no restrictions on the mutability of implementations, |
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* however immutability is strongly recommended. |
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* |
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* @since 1.8 |
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*/ |
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public interface TemporalAccessor { |
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/** |
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* Checks if the specified field is supported. |
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* <p> |
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* This checks if the date-time can be queried for the specified field. |
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* If false, then calling the {@link #range(TemporalField) range} and {@link #get(TemporalField) get} |
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* methods will throw an exception. |
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* |
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* @implSpec |
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* Implementations must check and handle all fields defined in {@link ChronoField}. |
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* If the field is supported, then true must be returned, otherwise false must be returned. |
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* <p> |
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* If the field is not a {@code ChronoField}, then the result of this method |
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* is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} |
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* passing {@code this} as the argument. |
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* <p> |
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* Implementations must ensure that no observable state is altered when this |
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* read-only method is invoked. |
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* |
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* @param field the field to check, null returns false |
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* @return true if this date-time can be queried for the field, false if not |
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*/ |
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boolean isSupported(TemporalField field); |
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/** |
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* Gets the range of valid values for the specified 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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* The value of this temporal object is used to enhance the accuracy of the returned range. |
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* If the date-time cannot return the range, because the field is unsupported or for |
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* some other reason, an exception will be thrown. |
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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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* @implSpec |
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* Implementations must check and handle all fields defined in {@link ChronoField}. |
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* If the field is supported, then the range of the field must be returned. |
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* If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown. |
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* <p> |
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* If the field is not a {@code ChronoField}, then the result of this method |
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* is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessorl)} |
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* passing {@code this} as the argument. |
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* <p> |
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* Implementations must ensure that no observable state is altered when this |
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* read-only method is invoked. |
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* <p> |
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* The default implementation must behave equivalent to this code: |
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* <pre> |
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* if (field instanceof ChronoField) { |
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* if (isSupported(field)) { |
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* return field.range(); |
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* } |
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* throw new UnsupportedTemporalTypeException("Unsupported field: " + field); |
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* } |
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* return field.rangeRefinedBy(this); |
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* </pre> |
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* |
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* @param field the field to query the range for, not null |
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* @return the range of valid values for the 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 |
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*/ |
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default ValueRange range(TemporalField field) { |
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if (field instanceof ChronoField) { |
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if (isSupported(field)) { |
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return field.range(); |
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} |
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throw new UnsupportedTemporalTypeException("Unsupported field: " + field); |
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} |
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Objects.requireNonNull(field, "field"); |
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return field.rangeRefinedBy(this); |
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} |
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/** |
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* Gets the value of the specified field as an {@code int}. |
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* <p> |
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24256
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scolebourne
parents:
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diff
changeset
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* This queries the date-time for the value of the specified field. |
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* The returned value will always be within the valid range of values for the field. |
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* If the date-time cannot return the value, because the field is unsupported or for |
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* some other reason, an exception will be thrown. |
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* |
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* @implSpec |
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* Implementations must check and handle all fields defined in {@link ChronoField}. |
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* If the field is supported and has an {@code int} range, then the value of |
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* the field must be returned. |
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* If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown. |
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* <p> |
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* If the field is not a {@code ChronoField}, then the result of this method |
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* is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} |
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* passing {@code this} as the argument. |
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* <p> |
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* Implementations must ensure that no observable state is altered when this |
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* read-only method is invoked. |
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* <p> |
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* The default implementation must behave equivalent to this code: |
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* <pre> |
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* if (range(field).isIntValue()) { |
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* return range(field).checkValidIntValue(getLong(field), field); |
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* } |
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* throw new UnsupportedTemporalTypeException("Invalid field " + field + " + for get() method, use getLong() instead"); |
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* </pre> |
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* |
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* @param field the field to get, not null |
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* @return the value for the field, within the valid range of values |
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* @throws DateTimeException if a value for the field cannot be obtained or |
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* the value is outside the range of valid values for the field |
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* @throws UnsupportedTemporalTypeException if the field is not supported or |
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* the range of values exceeds an {@code int} |
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* @throws ArithmeticException if numeric overflow occurs |
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*/ |
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default int get(TemporalField field) { |
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ValueRange range = range(field); |
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if (range.isIntValue() == false) { |
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throw new UnsupportedTemporalTypeException("Invalid field " + field + " for get() method, use getLong() instead"); |
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} |
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long value = getLong(field); |
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if (range.isValidValue(value) == false) { |
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throw new DateTimeException("Invalid value for " + field + " (valid values " + range + "): " + value); |
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} |
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return (int) value; |
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} |
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/** |
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* Gets the value of the specified field as a {@code long}. |
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* <p> |
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diff
changeset
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* This queries the date-time for the value of the specified field. |
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* The returned value may be outside the valid range of values for the field. |
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* If the date-time cannot return the value, because the field is unsupported or for |
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* some other reason, an exception will be thrown. |
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* |
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* @implSpec |
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* Implementations must check and handle all fields defined in {@link ChronoField}. |
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* If the field is supported, then the value of the field must be returned. |
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* If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown. |
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* <p> |
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* If the field is not a {@code ChronoField}, then the result of this method |
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* is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} |
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* passing {@code this} as the argument. |
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* <p> |
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* Implementations must ensure that no observable state is altered when this |
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* read-only method is invoked. |
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* |
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* @param field the field to get, not null |
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* @return the value for the field |
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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 |
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* @throws ArithmeticException if numeric overflow occurs |
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*/ |
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long getLong(TemporalField field); |
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/** |
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* Queries this date-time. |
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* <p> |
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* This queries this date-time using the specified query strategy object. |
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* <p> |
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* Queries are a key tool for extracting information from date-times. |
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* They exists to externalize the process of querying, permitting different |
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* approaches, as per the strategy design pattern. |
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* Examples might be a query that checks if the date is the day before February 29th |
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* in a leap year, or calculates the number of days to your next birthday. |
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* <p> |
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* The most common query implementations are method references, such as |
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* {@code LocalDate::from} and {@code ZoneId::from}. |
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* Additional implementations are provided as static methods on {@link TemporalQuery}. |
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* |
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* @implSpec |
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* The default implementation must behave equivalent to this code: |
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* <pre> |
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* if (query == TemporalQueries.zoneId() || |
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* query == TemporalQueries.chronology() || query == TemporalQueries.precision()) { |
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* return null; |
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* } |
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* return query.queryFrom(this); |
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* </pre> |
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* Future versions are permitted to add further queries to the if statement. |
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* <p> |
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* All classes implementing this interface and overriding this method must call |
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* {@code TemporalAccessor.super.query(query)}. JDK classes may avoid calling |
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* super if they provide behavior equivalent to the default behaviour, however |
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* non-JDK classes may not utilize this optimization and must call {@code super}. |
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* <p> |
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* If the implementation can supply a value for one of the queries listed in the |
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* if statement of the default implementation, then it must do so. |
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* For example, an application-defined {@code HourMin} class storing the hour |
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* and minute must override this method as follows: |
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* <pre> |
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* if (query == TemporalQueries.precision()) { |
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* return MINUTES; |
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* } |
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* return TemporalAccessor.super.query(query); |
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* </pre> |
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* <p> |
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* Implementations must ensure that no observable state is altered when this |
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* read-only method is invoked. |
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* |
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* @param <R> the type of the result |
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* @param query the query to invoke, not null |
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* @return the query result, null may be returned (defined by the query) |
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* @throws DateTimeException if unable to query |
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* @throws ArithmeticException if numeric overflow occurs |
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*/ |
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default <R> R query(TemporalQuery<R> query) { |
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if (query == TemporalQueries.zoneId() |
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|| query == TemporalQueries.chronology() |
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|| query == TemporalQueries.precision()) { |
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return null; |
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} |
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return query.queryFrom(this); |
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} |
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} |