1 /* 2 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file: 31 * 32 * Copyright (c) 2012, 2013 Stephen Colebourne & Michael Nascimento Santos 33 * 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions are met: 38 * 39 * * Redistributions of source code must retain the above copyright notice, 40 * this list of conditions and the following disclaimer. 41 * 42 * * Redistributions in binary form must reproduce the above copyright notice, 43 * this list of conditions and the following disclaimer in the documentation 44 * and/or other materials provided with the distribution. 45 * 46 * * Neither the name of JSR-310 nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 package java.time.temporal; 63 64 import java.time.DateTimeException; 65 import java.time.Duration; 66 import java.time.Period; 67 import java.util.List; 68 69 /** 70 * Framework-level interface defining an amount of time, such as 71 * "6 hours", "8 days" or "2 years and 3 months". 72 * <p> 73 * This is the base interface type for amounts of time. 74 * An amount is distinct from a date or time-of-day in that it is not tied 75 * to any specific point on the time-line. 76 * <p> 77 * The amount can be thought of as a {@code Map} of {@link TemporalUnit} to 78 * {@code long}, exposed via {@link #getUnits()} and {@link #get(TemporalUnit)}. 79 * A simple case might have a single unit-value pair, such as "6 hours". 80 * A more complex case may have multiple unit-value pairs, such as 81 * "7 years, 3 months and 5 days". 82 * <p> 83 * There are two common implementations. 84 * {@link Period} is a date-based implementation, storing years, months and days. 85 * {@link Duration} is a time-based implementation, storing seconds and nanoseconds, 86 * but providing some access using other duration based units such as minutes, 87 * hours and fixed 24-hour days. 88 * <p> 89 * This interface is a framework-level interface that should not be widely 90 * used in application code. Instead, applications should create and pass 91 * around instances of concrete types, such as {@code Period} and {@code Duration}. 92 * 93 * @implSpec 94 * This interface places no restrictions on the mutability of implementations, 95 * however immutability is strongly recommended. 96 * 97 * @since 1.8 98 */ 99 public interface TemporalAmount { 100 101 /** 102 * Returns the value of the requested unit. 103 * The units returned from {@link #getUnits()} uniquely define the 104 * value of the {@code TemporalAmount}. A value must be returned 105 * for each unit listed in {@code getUnits}. 106 * 107 * @implSpec 108 * Implementations may declare support for units not listed by {@link #getUnits()}. 109 * Typically, the implementation would define additional units 110 * as conversions for the convenience of developers. 111 * 112 * @param unit the {@code TemporalUnit} for which to return the value 113 * @return the long value of the unit 114 * @throws DateTimeException if a value for the unit cannot be obtained 115 * @throws UnsupportedTemporalTypeException if the {@code unit} is not supported 116 */ get(TemporalUnit unit)117 long get(TemporalUnit unit); 118 119 /** 120 * Returns the list of units uniquely defining the value of this TemporalAmount. 121 * The list of {@code TemporalUnits} is defined by the implementation class. 122 * The list is a snapshot of the units at the time {@code getUnits} 123 * is called and is not mutable. 124 * The units are ordered from longest duration to the shortest duration 125 * of the unit. 126 * 127 * @implSpec 128 * The list of units completely and uniquely represents the 129 * state of the object without omissions, overlaps or duplication. 130 * The units are in order from longest duration to shortest. 131 * 132 * @return the List of {@code TemporalUnits}; not null 133 */ getUnits()134 List<TemporalUnit> getUnits(); 135 136 /** 137 * Adds to the specified temporal object. 138 * <p> 139 * Adds the amount to the specified temporal object using the logic 140 * encapsulated in the implementing class. 141 * <p> 142 * There are two equivalent ways of using this method. 143 * The first is to invoke this method directly. 144 * The second is to use {@link Temporal#plus(TemporalAmount)}: 145 * <pre> 146 * // These two lines are equivalent, but the second approach is recommended 147 * dateTime = amount.addTo(dateTime); 148 * dateTime = dateTime.plus(adder); 149 * </pre> 150 * It is recommended to use the second approach, {@code plus(TemporalAmount)}, 151 * as it is a lot clearer to read in code. 152 * 153 * @implSpec 154 * The implementation must take the input object and add to it. 155 * The implementation defines the logic of the addition and is responsible for 156 * documenting that logic. It may use any method on {@code Temporal} to 157 * query the temporal object and perform the addition. 158 * The returned object must have the same observable type as the input object 159 * <p> 160 * The input object must not be altered. 161 * Instead, an adjusted copy of the original must be returned. 162 * This provides equivalent, safe behavior for immutable and mutable temporal objects. 163 * <p> 164 * The input temporal object may be in a calendar system other than ISO. 165 * Implementations may choose to document compatibility with other calendar systems, 166 * or reject non-ISO temporal objects by {@link TemporalQueries#chronology() querying the chronology}. 167 * <p> 168 * This method may be called from multiple threads in parallel. 169 * It must be thread-safe when invoked. 170 * 171 * @param temporal the temporal object to add the amount to, not null 172 * @return an object of the same observable type with the addition made, not null 173 * @throws DateTimeException if unable to add 174 * @throws ArithmeticException if numeric overflow occurs 175 */ addTo(Temporal temporal)176 Temporal addTo(Temporal temporal); 177 178 /** 179 * Subtracts this object from the specified temporal object. 180 * <p> 181 * Subtracts the amount from the specified temporal object using the logic 182 * encapsulated in the implementing class. 183 * <p> 184 * There are two equivalent ways of using this method. 185 * The first is to invoke this method directly. 186 * The second is to use {@link Temporal#minus(TemporalAmount)}: 187 * <pre> 188 * // these two lines are equivalent, but the second approach is recommended 189 * dateTime = amount.subtractFrom(dateTime); 190 * dateTime = dateTime.minus(amount); 191 * </pre> 192 * It is recommended to use the second approach, {@code minus(TemporalAmount)}, 193 * as it is a lot clearer to read in code. 194 * 195 * @implSpec 196 * The implementation must take the input object and subtract from it. 197 * The implementation defines the logic of the subtraction and is responsible for 198 * documenting that logic. It may use any method on {@code Temporal} to 199 * query the temporal object and perform the subtraction. 200 * The returned object must have the same observable type as the input object 201 * <p> 202 * The input object must not be altered. 203 * Instead, an adjusted copy of the original must be returned. 204 * This provides equivalent, safe behavior for immutable and mutable temporal objects. 205 * <p> 206 * The input temporal object may be in a calendar system other than ISO. 207 * Implementations may choose to document compatibility with other calendar systems, 208 * or reject non-ISO temporal objects by {@link TemporalQueries#chronology() querying the chronology}. 209 * <p> 210 * This method may be called from multiple threads in parallel. 211 * It must be thread-safe when invoked. 212 * 213 * @param temporal the temporal object to subtract the amount from, not null 214 * @return an object of the same observable type with the subtraction made, not null 215 * @throws DateTimeException if unable to subtract 216 * @throws ArithmeticException if numeric overflow occurs 217 */ subtractFrom(Temporal temporal)218 Temporal subtractFrom(Temporal temporal); 219 } 220