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, 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 66 /** 67 * Strategy for adjusting a temporal object. 68 * <p> 69 * Adjusters are a key tool for modifying temporal objects. 70 * They exist to externalize the process of adjustment, permitting different 71 * approaches, as per the strategy design pattern. 72 * Examples might be an adjuster that sets the date avoiding weekends, or one that 73 * sets the date to the last day of the month. 74 * <p> 75 * There are two equivalent ways of using a {@code TemporalAdjuster}. 76 * The first is to invoke the method on this interface directly. 77 * The second is to use {@link Temporal#with(TemporalAdjuster)}: 78 * <pre> 79 * // these two lines are equivalent, but the second approach is recommended 80 * temporal = thisAdjuster.adjustInto(temporal); 81 * temporal = temporal.with(thisAdjuster); 82 * </pre> 83 * It is recommended to use the second approach, {@code with(TemporalAdjuster)}, 84 * as it is a lot clearer to read in code. 85 * <p> 86 * The {@link TemporalAdjusters} class contains a standard set of adjusters, 87 * available as static methods. 88 * These include: 89 * <ul> 90 * <li>finding the first or last day of the month 91 * <li>finding the first day of next month 92 * <li>finding the first or last day of the year 93 * <li>finding the first day of next year 94 * <li>finding the first or last day-of-week within a month, such as "first Wednesday in June" 95 * <li>finding the next or previous day-of-week, such as "next Thursday" 96 * </ul> 97 * 98 * @implSpec 99 * This interface places no restrictions on the mutability of implementations, 100 * however immutability is strongly recommended. 101 * 102 * @see TemporalAdjusters 103 * @since 1.8 104 */ 105 @FunctionalInterface 106 public interface TemporalAdjuster { 107 108 /** 109 * Adjusts the specified temporal object. 110 * <p> 111 * This adjusts the specified temporal object using the logic 112 * encapsulated in the implementing class. 113 * Examples might be an adjuster that sets the date avoiding weekends, or one that 114 * sets the date to the last day of the month. 115 * <p> 116 * There are two equivalent ways of using this method. 117 * The first is to invoke this method directly. 118 * The second is to use {@link Temporal#with(TemporalAdjuster)}: 119 * <pre> 120 * // these two lines are equivalent, but the second approach is recommended 121 * temporal = thisAdjuster.adjustInto(temporal); 122 * temporal = temporal.with(thisAdjuster); 123 * </pre> 124 * It is recommended to use the second approach, {@code with(TemporalAdjuster)}, 125 * as it is a lot clearer to read in code. 126 * 127 * @implSpec 128 * The implementation must take the input object and adjust it. 129 * The implementation defines the logic of the adjustment and is responsible for 130 * documenting that logic. It may use any method on {@code Temporal} to 131 * query the temporal object and perform the adjustment. 132 * The returned object must have the same observable type as the input object 133 * <p> 134 * The input object must not be altered. 135 * Instead, an adjusted copy of the original must be returned. 136 * This provides equivalent, safe behavior for immutable and mutable temporal objects. 137 * <p> 138 * The input temporal object may be in a calendar system other than ISO. 139 * Implementations may choose to document compatibility with other calendar systems, 140 * or reject non-ISO temporal objects by {@link TemporalQueries#chronology() querying the chronology}. 141 * <p> 142 * This method may be called from multiple threads in parallel. 143 * It must be thread-safe when invoked. 144 * 145 * @param temporal the temporal object to adjust, not null 146 * @return an object of the same observable type with the adjustment made, not null 147 * @throws DateTimeException if unable to make the adjustment 148 * @throws ArithmeticException if numeric overflow occurs 149 */ adjustInto(Temporal temporal)150 Temporal adjustInto(Temporal temporal); 151 152 } 153