| /* |
| * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * 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. |
| * |
| * * Redistributions in binary form must reproduce the above copyright notice, |
| * this list of conditions and the following disclaimer in the documentation |
| * and/or other materials provided with the distribution. |
| * |
| * * Neither the name of JSR-310 nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| package java.time.chrono; |
| |
| import static java.time.temporal.ChronoField.ERA; |
| import static java.time.temporal.ChronoUnit.ERAS; |
| |
| import java.time.DateTimeException; |
| import java.time.temporal.UnsupportedTemporalTypeException; |
| import java.time.format.DateTimeFormatterBuilder; |
| import java.time.format.TextStyle; |
| import java.time.temporal.ChronoField; |
| import java.time.temporal.Temporal; |
| import java.time.temporal.TemporalAccessor; |
| import java.time.temporal.TemporalAdjuster; |
| import java.time.temporal.TemporalField; |
| import java.time.temporal.TemporalQueries; |
| import java.time.temporal.TemporalQuery; |
| import java.time.temporal.ValueRange; |
| import java.util.Locale; |
| |
| /** |
| * An era of the time-line. |
| * <p> |
| * Most calendar systems have a single epoch dividing the time-line into two eras. |
| * However, some calendar systems, have multiple eras, such as one for the reign |
| * of each leader. |
| * In all cases, the era is conceptually the largest division of the time-line. |
| * Each chronology defines the Era's that are known Eras and a |
| * {@link Chronology#eras Chronology.eras} to get the valid eras. |
| * <p> |
| * For example, the Thai Buddhist calendar system divides time into two eras, |
| * before and after a single date. By contrast, the Japanese calendar system |
| * has one era for the reign of each Emperor. |
| * <p> |
| * Instances of {@code Era} may be compared using the {@code ==} operator. |
| * |
| * @implSpec |
| * This interface must be implemented with care to ensure other classes operate correctly. |
| * All implementations must be singletons - final, immutable and thread-safe. |
| * It is recommended to use an enum whenever possible. |
| * |
| * @since 1.8 |
| */ |
| public interface Era extends TemporalAccessor, TemporalAdjuster { |
| |
| /** |
| * Gets the numeric value associated with the era as defined by the chronology. |
| * Each chronology defines the predefined Eras and methods to list the Eras |
| * of the chronology. |
| * <p> |
| * All fields, including eras, have an associated numeric value. |
| * The meaning of the numeric value for era is determined by the chronology |
| * according to these principles: |
| * <ul> |
| * <li>The era in use at the epoch 1970-01-01 (ISO) has the value 1. |
| * <li>Later eras have sequentially higher values. |
| * <li>Earlier eras have sequentially lower values, which may be negative. |
| * </ul> |
| * |
| * @return the numeric era value |
| */ |
| int getValue(); |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Checks if the specified field is supported. |
| * <p> |
| * This checks if this era can be queried for the specified field. |
| * If false, then calling the {@link #range(TemporalField) range} and |
| * {@link #get(TemporalField) get} methods will throw an exception. |
| * <p> |
| * If the field is a {@link ChronoField} then the query is implemented here. |
| * The {@code ERA} field returns true. |
| * All other {@code ChronoField} instances will return false. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} |
| * passing {@code this} as the argument. |
| * Whether the field is supported is determined by the field. |
| * |
| * @param field the field to check, null returns false |
| * @return true if the field is supported on this era, false if not |
| */ |
| @Override |
| default boolean isSupported(TemporalField field) { |
| if (field instanceof ChronoField) { |
| return field == ERA; |
| } |
| return field != null && field.isSupportedBy(this); |
| } |
| |
| /** |
| * Gets the range of valid values for the specified field. |
| * <p> |
| * The range object expresses the minimum and maximum valid values for a field. |
| * This era is used to enhance the accuracy of the returned range. |
| * If it is not possible to return the range, because the field is not supported |
| * or for some other reason, an exception is thrown. |
| * <p> |
| * If the field is a {@link ChronoField} then the query is implemented here. |
| * The {@code ERA} field returns the range. |
| * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)} |
| * passing {@code this} as the argument. |
| * Whether the range can be obtained is determined by the field. |
| * <p> |
| * The default implementation must return a range for {@code ERA} from |
| * zero to one, suitable for two era calendar systems such as ISO. |
| * |
| * @param field the field to query the range for, not null |
| * @return the range of valid values for the field, not null |
| * @throws DateTimeException if the range for the field cannot be obtained |
| * @throws UnsupportedTemporalTypeException if the unit is not supported |
| */ |
| @Override // override for Javadoc |
| default ValueRange range(TemporalField field) { |
| return TemporalAccessor.super.range(field); |
| } |
| |
| /** |
| * Gets the value of the specified field from this era as an {@code int}. |
| * <p> |
| * This queries this era for the value of the specified field. |
| * The returned value will always be within the valid range of values for the field. |
| * If it is not possible to return the value, because the field is not supported |
| * or for some other reason, an exception is thrown. |
| * <p> |
| * If the field is a {@link ChronoField} then the query is implemented here. |
| * The {@code ERA} field returns the value of the era. |
| * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} |
| * passing {@code this} as the argument. Whether the value can be obtained, |
| * and what the value represents, is determined by the field. |
| * |
| * @param field the field to get, not null |
| * @return the value for the field |
| * @throws DateTimeException if a value for the field cannot be obtained or |
| * the value is outside the range of valid values for the field |
| * @throws UnsupportedTemporalTypeException if the field is not supported or |
| * the range of values exceeds an {@code int} |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| @Override // override for Javadoc and performance |
| default int get(TemporalField field) { |
| if (field == ERA) { |
| return getValue(); |
| } |
| return TemporalAccessor.super.get(field); |
| } |
| |
| /** |
| * Gets the value of the specified field from this era as a {@code long}. |
| * <p> |
| * This queries this era for the value of the specified field. |
| * If it is not possible to return the value, because the field is not supported |
| * or for some other reason, an exception is thrown. |
| * <p> |
| * If the field is a {@link ChronoField} then the query is implemented here. |
| * The {@code ERA} field returns the value of the era. |
| * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} |
| * passing {@code this} as the argument. Whether the value can be obtained, |
| * and what the value represents, is determined by the field. |
| * |
| * @param field the field to get, not null |
| * @return the value for the field |
| * @throws DateTimeException if a value for the field cannot be obtained |
| * @throws UnsupportedTemporalTypeException if the field is not supported |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| @Override |
| default long getLong(TemporalField field) { |
| if (field == ERA) { |
| return getValue(); |
| } else if (field instanceof ChronoField) { |
| throw new UnsupportedTemporalTypeException("Unsupported field: " + field); |
| } |
| return field.getFrom(this); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Queries this era using the specified query. |
| * <p> |
| * This queries this era using the specified query strategy object. |
| * The {@code TemporalQuery} object defines the logic to be used to |
| * obtain the result. Read the documentation of the query to understand |
| * what the result of this method will be. |
| * <p> |
| * The result of this method is obtained by invoking the |
| * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the |
| * specified query passing {@code this} as the argument. |
| * |
| * @param <R> the type of the result |
| * @param query the query to invoke, not null |
| * @return the query result, null may be returned (defined by the query) |
| * @throws DateTimeException if unable to query (defined by the query) |
| * @throws ArithmeticException if numeric overflow occurs (defined by the query) |
| */ |
| @SuppressWarnings("unchecked") |
| @Override |
| default <R> R query(TemporalQuery<R> query) { |
| if (query == TemporalQueries.precision()) { |
| return (R) ERAS; |
| } |
| return TemporalAccessor.super.query(query); |
| } |
| |
| /** |
| * Adjusts the specified temporal object to have the same era as this object. |
| * <p> |
| * This returns a temporal object of the same observable type as the input |
| * with the era changed to be the same as this. |
| * <p> |
| * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)} |
| * passing {@link ChronoField#ERA} as the field. |
| * <p> |
| * In most cases, it is clearer to reverse the calling pattern by using |
| * {@link Temporal#with(TemporalAdjuster)}: |
| * <pre> |
| * // these two lines are equivalent, but the second approach is recommended |
| * temporal = thisEra.adjustInto(temporal); |
| * temporal = temporal.with(thisEra); |
| * </pre> |
| * <p> |
| * This instance is immutable and unaffected by this method call. |
| * |
| * @param temporal the target object to be adjusted, not null |
| * @return the adjusted object, not null |
| * @throws DateTimeException if unable to make the adjustment |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| @Override |
| default Temporal adjustInto(Temporal temporal) { |
| return temporal.with(ERA, getValue()); |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the textual representation of this era. |
| * <p> |
| * This returns the textual name used to identify the era, |
| * suitable for presentation to the user. |
| * The parameters control the style of the returned text and the locale. |
| * <p> |
| * If no textual mapping is found then the {@link #getValue() numeric value} is returned. |
| * |
| * @apiNote This default implementation is suitable for most implementations. |
| * |
| * @param style the style of the text required, not null |
| * @param locale the locale to use, not null |
| * @return the text value of the era, not null |
| */ |
| default String getDisplayName(TextStyle style, Locale locale) { |
| return new DateTimeFormatterBuilder().appendText(ERA, style).toFormatter(locale).format(this); |
| } |
| |
| // NOTE: methods to convert year-of-era/proleptic-year cannot be here as they may depend on month/day (Japanese) |
| } |