Java tutorial
/* * Copyright (c) 2012, 2013, 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; /** * Strategy for adjusting a temporal object. * <p> * Adjusters are a key tool for modifying temporal objects. * They exist to externalize the process of adjustment, permitting different * approaches, as per the strategy design pattern. * Examples might be an adjuster that sets the date avoiding weekends, or one that * sets the date to the last day of the month. * <p> * There are two equivalent ways of using a {@code TemporalAdjuster}. * The first is to invoke the method on this interface directly. * The second is to use {@link Temporal#with(TemporalAdjuster)}: * <pre> * // these two lines are equivalent, but the second approach is recommended * temporal = thisAdjuster.adjustInto(temporal); * temporal = temporal.with(thisAdjuster); * </pre> * It is recommended to use the second approach, {@code with(TemporalAdjuster)}, * as it is a lot clearer to read in code. * <p> * The {@link TemporalAdjusters} class contains a standard set of adjusters, * available as static methods. * These include: * <ul> * <li>finding the first or last day of the month * <li>finding the first day of next month * <li>finding the first or last day of the year * <li>finding the first day of next year * <li>finding the first or last day-of-week within a month, such as "first Wednesday in June" * <li>finding the next or previous day-of-week, such as "next Thursday" * </ul> * * @implSpec * This interface places no restrictions on the mutability of implementations, * however immutability is strongly recommended. * * @see TemporalAdjusters * @since 1.8 */ @FunctionalInterface public interface TemporalAdjuster { /** * Adjusts the specified temporal object. * <p> * This adjusts the specified temporal object using the logic * encapsulated in the implementing class. * Examples might be an adjuster that sets the date avoiding weekends, or one that * sets the date to the last day of the month. * <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#with(TemporalAdjuster)}: * <pre> * // these two lines are equivalent, but the second approach is recommended * temporal = thisAdjuster.adjustInto(temporal); * temporal = temporal.with(thisAdjuster); * </pre> * It is recommended to use the second approach, {@code with(TemporalAdjuster)}, * as it is a lot clearer to read in code. * * @implSpec * The implementation must take the input object and adjust it. * The implementation defines the logic of the adjustment and is responsible for * documenting that logic. It may use any method on {@code Temporal} to * query the temporal object and perform the adjustment. * 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 adjust, not null * @return an object of the same observable type with the adjustment made, not null * @throws DateTimeException if unable to make the adjustment * @throws ArithmeticException if numeric overflow occurs */ Temporal adjustInto(Temporal temporal); }