| /* |
| * Copyright (c) 2012, 2015, 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.temporal; |
| |
| import java.time.DateTimeException; |
| import java.time.Duration; |
| import java.time.LocalTime; |
| import java.time.Period; |
| import java.time.chrono.ChronoLocalDate; |
| import java.time.chrono.ChronoLocalDateTime; |
| import java.time.chrono.ChronoZonedDateTime; |
| |
| /** |
| * A unit of date-time, such as Days or Hours. |
| * <p> |
| * Measurement of time is built on units, such as years, months, days, hours, minutes and seconds. |
| * Implementations of this interface represent those units. |
| * <p> |
| * An instance of this interface represents the unit itself, rather than an amount of the unit. |
| * See {@link Period} for a class that represents an amount in terms of the common units. |
| * <p> |
| * The most commonly used units are defined in {@link ChronoUnit}. |
| * Further units are supplied in {@link IsoFields}. |
| * Units can also be written by application code by implementing this interface. |
| * <p> |
| * The unit works using double dispatch. Client code calls methods on a date-time like |
| * {@code LocalDateTime} which check if the unit is a {@code ChronoUnit}. |
| * If it is, then the date-time must handle it. |
| * Otherwise, the method call is re-dispatched to the matching method in this interface. |
| * |
| * @implSpec |
| * This interface must be implemented with care to ensure other classes operate correctly. |
| * All implementations that can be instantiated must be final, immutable and thread-safe. |
| * It is recommended to use an enum where possible. |
| * |
| * @since 1.8 |
| */ |
| public interface TemporalUnit { |
| |
| /** |
| * Gets the duration of this unit, which may be an estimate. |
| * <p> |
| * All units return a duration measured in standard nanoseconds from this method. |
| * The duration will be positive and non-zero. |
| * For example, an hour has a duration of {@code 60 * 60 * 1,000,000,000ns}. |
| * <p> |
| * Some units may return an accurate duration while others return an estimate. |
| * For example, days have an estimated duration due to the possibility of |
| * daylight saving time changes. |
| * To determine if the duration is an estimate, use {@link #isDurationEstimated()}. |
| * |
| * @return the duration of this unit, which may be an estimate, not null |
| */ |
| Duration getDuration(); |
| |
| /** |
| * Checks if the duration of the unit is an estimate. |
| * <p> |
| * All units have a duration, however the duration is not always accurate. |
| * For example, days have an estimated duration due to the possibility of |
| * daylight saving time changes. |
| * This method returns true if the duration is an estimate and false if it is |
| * accurate. Note that accurate/estimated ignores leap seconds. |
| * |
| * @return true if the duration is estimated, false if accurate |
| */ |
| boolean isDurationEstimated(); |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Checks if this unit represents a component of a date. |
| * <p> |
| * A date is time-based if it can be used to imply meaning from a date. |
| * It must have a {@linkplain #getDuration() duration} that is an integral |
| * multiple of the length of a standard day. |
| * Note that it is valid for both {@code isDateBased()} and {@code isTimeBased()} |
| * to return false, such as when representing a unit like 36 hours. |
| * |
| * @return true if this unit is a component of a date |
| */ |
| boolean isDateBased(); |
| |
| /** |
| * Checks if this unit represents a component of a time. |
| * <p> |
| * A unit is time-based if it can be used to imply meaning from a time. |
| * It must have a {@linkplain #getDuration() duration} that divides into |
| * the length of a standard day without remainder. |
| * Note that it is valid for both {@code isDateBased()} and {@code isTimeBased()} |
| * to return false, such as when representing a unit like 36 hours. |
| * |
| * @return true if this unit is a component of a time |
| */ |
| boolean isTimeBased(); |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Checks if this unit is supported by the specified temporal object. |
| * <p> |
| * This checks that the implementing date-time can add/subtract this unit. |
| * This can be used to avoid throwing an exception. |
| * <p> |
| * This default implementation derives the value using |
| * {@link Temporal#plus(long, TemporalUnit)}. |
| * |
| * @param temporal the temporal object to check, not null |
| * @return true if the unit is supported |
| */ |
| default boolean isSupportedBy(Temporal temporal) { |
| if (temporal instanceof LocalTime) { |
| return isTimeBased(); |
| } |
| if (temporal instanceof ChronoLocalDate) { |
| return isDateBased(); |
| } |
| if (temporal instanceof ChronoLocalDateTime || temporal instanceof ChronoZonedDateTime) { |
| return true; |
| } |
| try { |
| temporal.plus(1, this); |
| return true; |
| } catch (UnsupportedTemporalTypeException ex) { |
| return false; |
| } catch (RuntimeException ex) { |
| try { |
| temporal.plus(-1, this); |
| return true; |
| } catch (RuntimeException ex2) { |
| return false; |
| } |
| } |
| } |
| |
| /** |
| * Returns a copy of the specified temporal object with the specified period added. |
| * <p> |
| * The period added is a multiple of this unit. For example, this method |
| * could be used to add "3 days" to a date by calling this method on the |
| * instance representing "days", passing the date and the period "3". |
| * The period to be added may be negative, which is equivalent to subtraction. |
| * <p> |
| * There are two equivalent ways of using this method. |
| * The first is to invoke this method directly. |
| * The second is to use {@link Temporal#plus(long, TemporalUnit)}: |
| * <pre> |
| * // these two lines are equivalent, but the second approach is recommended |
| * temporal = thisUnit.addTo(temporal); |
| * temporal = temporal.plus(thisUnit); |
| * </pre> |
| * It is recommended to use the second approach, {@code plus(TemporalUnit)}, |
| * as it is a lot clearer to read in code. |
| * <p> |
| * Implementations should perform any queries or calculations using the units |
| * available in {@link ChronoUnit} or the fields available in {@link ChronoField}. |
| * If the unit is not supported an {@code UnsupportedTemporalTypeException} must be thrown. |
| * <p> |
| * Implementations must not alter the specified temporal object. |
| * Instead, an adjusted copy of the original must be returned. |
| * This provides equivalent, safe behavior for immutable and mutable implementations. |
| * |
| * @param <R> the type of the Temporal object |
| * @param temporal the temporal object to adjust, not null |
| * @param amount the amount of this unit to add, positive or negative |
| * @return the adjusted temporal object, not null |
| * @throws DateTimeException if the amount cannot be added |
| * @throws UnsupportedTemporalTypeException if the unit is not supported by the temporal |
| */ |
| <R extends Temporal> R addTo(R temporal, long amount); |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Calculates the amount of time between two temporal objects. |
| * <p> |
| * This calculates the amount in terms of this unit. The start and end |
| * points are supplied as temporal objects and must be of compatible types. |
| * The implementation will convert the second type to be an instance of the |
| * first type before the calculating the amount. |
| * The result will be negative if the end is before the start. |
| * For example, the amount in hours between two temporal objects can be |
| * calculated using {@code HOURS.between(startTime, endTime)}. |
| * <p> |
| * The calculation returns a whole number, representing the number of |
| * complete units between the two temporals. |
| * For example, the amount in hours between the times 11:30 and 13:29 |
| * will only be one hour as it is one minute short of two hours. |
| * <p> |
| * There are two equivalent ways of using this method. |
| * The first is to invoke this method directly. |
| * The second is to use {@link Temporal#until(Temporal, TemporalUnit)}: |
| * <pre> |
| * // these two lines are equivalent |
| * between = thisUnit.between(start, end); |
| * between = start.until(end, thisUnit); |
| * </pre> |
| * The choice should be made based on which makes the code more readable. |
| * <p> |
| * For example, this method allows the number of days between two dates to |
| * be calculated: |
| * <pre> |
| * long daysBetween = DAYS.between(start, end); |
| * // or alternatively |
| * long daysBetween = start.until(end, DAYS); |
| * </pre> |
| * <p> |
| * Implementations should perform any queries or calculations using the units |
| * available in {@link ChronoUnit} or the fields available in {@link ChronoField}. |
| * If the unit is not supported an {@code UnsupportedTemporalTypeException} must be thrown. |
| * Implementations must not alter the specified temporal objects. |
| * |
| * @implSpec |
| * Implementations must begin by checking to if the two temporals have the |
| * same type using {@code getClass()}. If they do not, then the result must be |
| * obtained by calling {@code temporal1Inclusive.until(temporal2Exclusive, this)}. |
| * |
| * @param temporal1Inclusive the base temporal object, not null |
| * @param temporal2Exclusive the other temporal object, exclusive, not null |
| * @return the amount of time between temporal1Inclusive and temporal2Exclusive |
| * in terms of this unit; positive if temporal2Exclusive is later than |
| * temporal1Inclusive, negative if earlier |
| * @throws DateTimeException if the amount cannot be calculated, or the end |
| * temporal cannot be converted to the same type as the start temporal |
| * @throws UnsupportedTemporalTypeException if the unit is not supported by the temporal |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| long between(Temporal temporal1Inclusive, Temporal temporal2Exclusive); |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Gets a descriptive name for the unit. |
| * <p> |
| * This should be in the plural and upper-first camel case, such as 'Days' or 'Minutes'. |
| * |
| * @return the name of this unit, not null |
| */ |
| @Override |
| String toString(); |
| |
| } |
