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 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
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package java.time.temporal;

import java.time.DateTimeException;


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 TemporalAdjuster. The first is to invoke the method on this interface directly. The second is to use 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, with(TemporalAdjuster), as it is a lot clearer to read in code. 
 The TemporalAdjusters class contains a standard set of adjusters, available as static methods. These include: 
    

  • finding the first or last day of the month

  • finding the first day of next month

  • finding the first or last day of the year

  • finding the first day of next year

  • finding the first or last day-of-week within a month, such as "first Wednesday in June"

  • finding the next or previous day-of-week, such as "next Thursday"



See Also:
Implementation Requirements:
This interface places no restrictions on the mutability of implementations,
however immutability is strongly recommended.
Since:1.8
/**
 * 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.


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 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, with(TemporalAdjuster), as it is a lot clearer to read in code. 
Params:
  • temporal –  the temporal object to adjust, not null
Throws:
Implementation Requirements: 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 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 querying the chronology. 

This method may be called from multiple threads in parallel.
It must be thread-safe when invoked.
Returns:an object of the same observable type with the adjustment made, not null
/**
     * 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);

}