| /* |
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| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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| |
| /* |
| * 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, 2013 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 |
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| * |
| * * 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 |
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| */ |
| package java.time.temporal; |
| |
| import java.time.DateTimeException; |
| import java.time.Duration; |
| import java.time.Period; |
| import java.util.List; |
| |
| /** |
| * Framework-level interface defining an amount of time, such as |
| * "6 hours", "8 days" or "2 years and 3 months". |
| * <p> |
| * This is the base interface type for amounts of time. |
| * An amount is distinct from a date or time-of-day in that it is not tied |
| * to any specific point on the time-line. |
| * <p> |
| * The amount can be thought of as a {@code Map} of {@link TemporalUnit} to |
| * {@code long}, exposed via {@link #getUnits()} and {@link #get(TemporalUnit)}. |
| * A simple case might have a single unit-value pair, such as "6 hours". |
| * A more complex case may have multiple unit-value pairs, such as |
| * "7 years, 3 months and 5 days". |
| * <p> |
| * There are two common implementations. |
| * {@link Period} is a date-based implementation, storing years, months and days. |
| * {@link Duration} is a time-based implementation, storing seconds and nanoseconds, |
| * but providing some access using other duration based units such as minutes, |
| * hours and fixed 24-hour days. |
| * <p> |
| * This interface is a framework-level interface that should not be widely |
| * used in application code. Instead, applications should create and pass |
| * around instances of concrete types, such as {@code Period} and {@code Duration}. |
| * |
| * @implSpec |
| * This interface places no restrictions on the mutability of implementations, |
| * however immutability is strongly recommended. |
| * |
| * @since 1.8 |
| */ |
| public interface TemporalAmount { |
| |
| /** |
| * Returns the value of the requested unit. |
| * The units returned from {@link #getUnits()} uniquely define the |
| * value of the {@code TemporalAmount}. A value must be returned |
| * for each unit listed in {@code getUnits}. |
| * |
| * @implSpec |
| * Implementations may declare support for units not listed by {@link #getUnits()}. |
| * Typically, the implementation would define additional units |
| * as conversions for the convenience of developers. |
| * |
| * @param unit the {@code TemporalUnit} for which to return the value |
| * @return the long value of the unit |
| * @throws DateTimeException if a value for the unit cannot be obtained |
| * @throws UnsupportedTemporalTypeException if the {@code unit} is not supported |
| */ |
| long get(TemporalUnit unit); |
| |
| /** |
| * Returns the list of units uniquely defining the value of this TemporalAmount. |
| * The list of {@code TemporalUnits} is defined by the implementation class. |
| * The list is a snapshot of the units at the time {@code getUnits} |
| * is called and is not mutable. |
| * The units are ordered from longest duration to the shortest duration |
| * of the unit. |
| * |
| * @implSpec |
| * The list of units completely and uniquely represents the |
| * state of the object without omissions, overlaps or duplication. |
| * The units are in order from longest duration to shortest. |
| * |
| * @return the List of {@code TemporalUnits}; not null |
| */ |
| List<TemporalUnit> getUnits(); |
| |
| /** |
| * Adds to the specified temporal object. |
| * <p> |
| * Adds the amount to the specified temporal object using the logic |
| * encapsulated in the implementing class. |
| * <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(TemporalAmount)}: |
| * <pre> |
| * // These two lines are equivalent, but the second approach is recommended |
| * dateTime = amount.addTo(dateTime); |
| * dateTime = dateTime.plus(adder); |
| * </pre> |
| * It is recommended to use the second approach, {@code plus(TemporalAmount)}, |
| * as it is a lot clearer to read in code. |
| * |
| * @implSpec |
| * The implementation must take the input object and add to it. |
| * The implementation defines the logic of the addition and is responsible for |
| * documenting that logic. It may use any method on {@code Temporal} to |
| * query the temporal object and perform the addition. |
| * The returned object must have the same observable type as the input object |
| * <p> |
| * The input object must not be altered. |
| * Instead, an adjusted copy of the original must be returned. |
| * This provides equivalent, safe behavior for immutable and mutable temporal objects. |
| * <p> |
| * The input temporal object may be in a calendar system other than ISO. |
| * Implementations may choose to document compatibility with other calendar systems, |
| * or reject non-ISO temporal objects by {@link TemporalQueries#chronology() querying the chronology}. |
| * <p> |
| * This method may be called from multiple threads in parallel. |
| * It must be thread-safe when invoked. |
| * |
| * @param temporal the temporal object to add the amount to, not null |
| * @return an object of the same observable type with the addition made, not null |
| * @throws DateTimeException if unable to add |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| Temporal addTo(Temporal temporal); |
| |
| /** |
| * Subtracts this object from the specified temporal object. |
| * <p> |
| * Subtracts the amount from the specified temporal object using the logic |
| * encapsulated in the implementing class. |
| * <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#minus(TemporalAmount)}: |
| * <pre> |
| * // these two lines are equivalent, but the second approach is recommended |
| * dateTime = amount.subtractFrom(dateTime); |
| * dateTime = dateTime.minus(amount); |
| * </pre> |
| * It is recommended to use the second approach, {@code minus(TemporalAmount)}, |
| * as it is a lot clearer to read in code. |
| * |
| * @implSpec |
| * The implementation must take the input object and subtract from it. |
| * The implementation defines the logic of the subtraction and is responsible for |
| * documenting that logic. It may use any method on {@code Temporal} to |
| * query the temporal object and perform the subtraction. |
| * The returned object must have the same observable type as the input object |
| * <p> |
| * The input object must not be altered. |
| * Instead, an adjusted copy of the original must be returned. |
| * This provides equivalent, safe behavior for immutable and mutable temporal objects. |
| * <p> |
| * The input temporal object may be in a calendar system other than ISO. |
| * Implementations may choose to document compatibility with other calendar systems, |
| * or reject non-ISO temporal objects by {@link TemporalQueries#chronology() querying the chronology}. |
| * <p> |
| * This method may be called from multiple threads in parallel. |
| * It must be thread-safe when invoked. |
| * |
| * @param temporal the temporal object to subtract the amount from, not null |
| * @return an object of the same observable type with the subtraction made, not null |
| * @throws DateTimeException if unable to subtract |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| Temporal subtractFrom(Temporal temporal); |
| } |