org.threeten.bp.temporal.TemporalAdjuster.scala Maven / Gradle / Ivy

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/*
 * Copyright (c) 2007-present, 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:
 *
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 *    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
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package org.threeten.bp.temporal

/**
 * Strategy for adjusting a temporal object.
 *
 * 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.
 *
 * 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)}:
 *  // these two lines are equivalent, but the second approach is recommended temporal =
 * thisAdjuster.adjustInto(temporal); temporal = temporal.with(thisAdjuster);  It is
 * recommended to use the second approach, {@code with(TemporalAdjuster)}, as it is a lot clearer to
 * read in code.
 *
 * See {@link TemporalAdjusters} for a standard set of adjusters, including finding the last day of
 * the month. Adjusters may also be defined by applications.
 *
 * Specification for implementors This interface places no restrictions on the mutability
 * of implementations, however immutability is strongly recommended.
 */
trait TemporalAdjuster {

  /**
   * Adjusts the specified temporal object.
   *
   * 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.
   *
   * 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)}:  // these two
   * lines are equivalent, but the second approach is recommended temporal =
   * thisAdjuster.adjustInto(temporal); temporal = temporal.with(thisAdjuster);  It is
   * recommended to use the second approach, {@code with(TemporalAdjuster)}, as it is a lot clearer
   * to read in code.
   *
   * Specification for implementors 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
   *
   * 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.
   *
   * 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}.
   *
   * 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
   */
  def adjustInto(temporal: Temporal): Temporal
}