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  /*
   * 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.
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  package java.time.temporal;
  
  import java.time.DateTimeException;
  import java.time.chrono.Chronology;
  import java.time.format.ResolverStyle;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * A field of date-time, such as month-of-year or hour-of-minute.
   * <p>
   * Date and time is expressed using fields which partition the time-line into something
   * meaningful for humans. Implementations of this interface represent those fields.
   * <p>
   * The most commonly used units are defined in {@link ChronoField}.
   * Further fields are supplied in {@link IsoFields}, {@link WeekFields} and {@link JulianFields}.
   * Fields can also be written by application code by implementing this interface.
   * <p>
   * The field works using double dispatch. Client code calls methods on a date-time like
   * {@code LocalDateTime} which check if the field is a {@code ChronoField}.
   * If it is, then the date-time must handle it.
   * Otherwise, the method call is re-dispatched to the matching method in this interface.
   *
   * @implSpec
   * This interface must be implemented with care to ensure other classes operate correctly.
   * All implementations that can be instantiated must be final, immutable and thread-safe.
   * Implementations should be {@code Serializable} where possible.
   * An enum is as effective implementation choice.
   *
   * @since 1.8
   */
  public interface TemporalField {
  
      /**
       * Gets the display name for the field in the requested locale.
       * <p>
       * If there is no display name for the locale then a suitable default must be returned.
       * <p>
       * The default implementation must check the locale is not null
       * and return {@code toString()}.
       *
       * @param locale  the locale to use, not null
       * @return the display name for the locale or a suitable default, not null
       */
      default String getDisplayName(Locale locale) {
          Objects.requireNonNull(locale, "locale");
          return toString();
      }
  
      /**
       * Gets the unit that the field is measured in.
       * <p>
       * The unit of the field is the period that varies within the range.
       * For example, in the field 'MonthOfYear', the unit is 'Months'.
       * See also {@link #getRangeUnit()}.
       *
       * @return the unit defining the base unit of the field, not null
       */
      TemporalUnit getBaseUnit();
  
      /**
       * Gets the range that the field is bound by.
       * <p>
       * The range of the field is the period that the field varies within.
       * For example, in the field 'MonthOfYear', the range is 'Years'.
       * See also {@link #getBaseUnit()}.
       * <p>
       * The range is never null. For example, the 'Year' field is shorthand for
       * 'YearOfForever'. It therefore has a unit of 'Years' and a range of 'Forever'.
       *
       * @return the unit defining the range of the field, not null
       */
      TemporalUnit getRangeUnit();
  
      /**
       * Gets the range of valid values for the field.
       * <p>
       * All fields can be expressed as a {@code long} integer.
       * This method returns an object that describes the valid range for that value.
       * This method is generally only applicable to the ISO-8601 calendar system.
       * <p>
       * Note that the result only describes the minimum and maximum valid values
       * and it is important not to read too much into them. For example, there
       * could be values within the range that are invalid for the field.
       *
       * @return the range of valid values for the field, not null
       */
      ValueRange range();
  
      //-----------------------------------------------------------------------
      /**
       * Checks if this field represents a component of a date.
       * <p>
       * A field is date-based if it can be derived from
       * {@link ChronoField#EPOCH_DAY EPOCH_DAY}.
       * Note that it is valid for both {@code isDateBased()} and {@code isTimeBased()}
       * to return false, such as when representing a field like minute-of-week.
       *
       * @return true if this field is a component of a date
       */
      boolean isDateBased();
  
      /**
       * Checks if this field represents a component of a time.
       * <p>
       * A field is time-based if it can be derived from
       * {@link ChronoField#NANO_OF_DAY NANO_OF_DAY}.
       * Note that it is valid for both {@code isDateBased()} and {@code isTimeBased()}
       * to return false, such as when representing a field like minute-of-week.
       *
       * @return true if this field is a component of a time
       */
      boolean isTimeBased();
  
      //-----------------------------------------------------------------------
      /**
       * Checks if this field is supported by the temporal object.
       * <p>
       * This determines whether the temporal accessor supports this field.
       * If this returns false, then the temporal cannot be queried for this field.
       * <p>
       * There are two equivalent ways of using this method.
       * The first is to invoke this method directly.
       * The second is to use {@link TemporalAccessor#isSupported(TemporalField)}:
       * <pre>
       *   // these two lines are equivalent, but the second approach is recommended
       *   temporal = thisField.isSupportedBy(temporal);
       *   temporal = temporal.isSupported(thisField);
       * </pre>
       * It is recommended to use the second approach, {@code isSupported(TemporalField)},
       * as it is a lot clearer to read in code.
       * <p>
       * Implementations should determine whether they are supported using the fields
       * available in {@link ChronoField}.
       *
       * @param temporal  the temporal object to query, not null
       * @return true if the date-time can be queried for this field, false if not
       */
      boolean isSupportedBy(TemporalAccessor temporal);
  
      /**
       * Get the range of valid values for this field using the temporal object to
       * refine the result.
       * <p>
       * This uses the temporal object to find the range of valid values for the field.
       * This is similar to {@link #range()}, however this method refines the result
       * using the temporal. For example, if the field is {@code DAY_OF_MONTH} the
       * {@code range} method is not accurate as there are four possible month lengths,
       * 28, 29, 30 and 31 days. Using this method with a date allows the range to be
       * accurate, returning just one of those four options.
       * <p>
       * There are two equivalent ways of using this method.
       * The first is to invoke this method directly.
       * The second is to use {@link TemporalAccessor#range(TemporalField)}:
       * <pre>
       *   // these two lines are equivalent, but the second approach is recommended
       *   temporal = thisField.rangeRefinedBy(temporal);
       *   temporal = temporal.range(thisField);
       * </pre>
       * It is recommended to use the second approach, {@code range(TemporalField)},
       * as it is a lot clearer to read in code.
       * <p>
       * Implementations should perform any queries or calculations using the fields
       * available in {@link ChronoField}.
       * If the field is not supported an {@code UnsupportedTemporalTypeException} must be thrown.
       *
       * @param temporal  the temporal object used to refine the result, not null
       * @return the range of valid values for this field, not null
       * @throws DateTimeException if the range for the field cannot be obtained
       * @throws UnsupportedTemporalTypeException if the field is not supported by the temporal
       */
      ValueRange rangeRefinedBy(TemporalAccessor temporal);
  
      /**
       * Gets the value of this field from the specified temporal object.
       * <p>
       * This queries the temporal object for the value of this field.
       * <p>
       * There are two equivalent ways of using this method.
       * The first is to invoke this method directly.
       * The second is to use {@link TemporalAccessor#getLong(TemporalField)}
       * (or {@link TemporalAccessor#get(TemporalField)}):
       * <pre>
       *   // these two lines are equivalent, but the second approach is recommended
       *   temporal = thisField.getFrom(temporal);
       *   temporal = temporal.getLong(thisField);
       * </pre>
       * It is recommended to use the second approach, {@code getLong(TemporalField)},
       * as it is a lot clearer to read in code.
       * <p>
       * Implementations should perform any queries or calculations using the fields
       * available in {@link ChronoField}.
       * If the field is not supported an {@code UnsupportedTemporalTypeException} must be thrown.
       *
       * @param temporal  the temporal object to query, not null
       * @return the value of this field, not null
       * @throws DateTimeException if a value for the field cannot be obtained
       * @throws UnsupportedTemporalTypeException if the field is not supported by the temporal
       * @throws ArithmeticException if numeric overflow occurs
       */
      long getFrom(TemporalAccessor temporal);
  
      /**
       * Returns a copy of the specified temporal object with the value of this field set.
       * <p>
       * This returns a new temporal object based on the specified one with the value for
       * this field changed. For example, on a {@code LocalDate}, this could be used to
       * set the year, month or day-of-month.
       * The returned object has the same observable type as the specified object.
       * <p>
       * In some cases, changing a field is not fully defined. For example, if the target object is
       * a date representing the 31st January, then changing the month to February would be unclear.
       * In cases like this, the implementation is responsible for resolving the result.
       * Typically it will choose the previous valid date, which would be the last valid
       * day of February in this example.
       * <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(TemporalField, long)}:
       * <pre>
       *   // these two lines are equivalent, but the second approach is recommended
       *   temporal = thisField.adjustInto(temporal);
       *   temporal = temporal.with(thisField);
       * </pre>
       * It is recommended to use the second approach, {@code with(TemporalField)},
       * as it is a lot clearer to read in code.
       * <p>
       * Implementations should perform any queries or calculations using the fields
       * available in {@link ChronoField}.
       * If the field is not supported an {@code UnsupportedTemporalTypeException} must be thrown.
       * <p>
       * Implementations must not alter the specified temporal object.
       * Instead, an adjusted copy of the original must be returned.
       * This provides equivalent, safe behavior for immutable and mutable implementations.
       *
       * @param <R>  the type of the Temporal object
       * @param temporal the temporal object to adjust, not null
       * @param newValue the new value of the field
       * @return the adjusted temporal object, not null
       * @throws DateTimeException if the field cannot be set
       * @throws UnsupportedTemporalTypeException if the field is not supported by the temporal
       * @throws ArithmeticException if numeric overflow occurs
       */
      <R extends Temporal> R adjustInto(R temporal, long newValue);
  
      /**
       * Resolves this field to provide a simpler alternative or a date.
       * <p>
       * This method is invoked during the resolve phase of parsing.
       * It is designed to allow application defined fields to be simplified into
       * more standard fields, such as those on {@code ChronoField}, or into a date.
       * <p>
       * Applications should not normally invoke this method directly.
       *
       * @implSpec
       * If an implementation represents a field that can be simplified, or
       * combined with others, then this method must be implemented.
       * <p>
       * The specified map contains the current state of the parse.
       * The map is mutable and must be mutated to resolve the field and
       * any related fields. This method will only be invoked during parsing
       * if the map contains this field, and implementations should therefore
       * assume this field is present.
       * <p>
       * Resolving a field will consist of looking at the value of this field,
       * and potentially other fields, and either updating the map with a
       * simpler value, such as a {@code ChronoField}, or returning a
       * complete {@code ChronoLocalDate}. If a resolve is successful,
       * the code must remove all the fields that were resolved from the map,
       * including this field.
       * <p>
       * For example, the {@code IsoFields} class contains the quarter-of-year
       * and day-of-quarter fields. The implementation of this method in that class
       * resolves the two fields plus the {@link ChronoField#YEAR YEAR} into a
       * complete {@code LocalDate}. The resolve method will remove all three
       * fields from the map before returning the {@code LocalDate}.
       * <p>
       * A partially complete temporal is used to allow the chronology and zone
       * to be queried. In general, only the chronology will be needed.
       * Querying items other than the zone or chronology is undefined and
       * must not be relied on.
       * The behavior of other methods such as {@code get}, {@code getLong},
       * {@code range} and {@code isSupported} is unpredictable and the results undefined.
       * <p>
       * If resolution should be possible, but the data is invalid, the resolver
       * style should be used to determine an appropriate level of leniency, which
       * may require throwing a {@code DateTimeException} or {@code ArithmeticException}.
       * If no resolution is possible, the resolve method must return null.
       * <p>
       * When resolving time fields, the map will be altered and null returned.
       * When resolving date fields, the date is normally returned from the method,
       * with the map altered to remove the resolved fields. However, it would also
       * be acceptable for the date fields to be resolved into other {@code ChronoField}
       * instances that can produce a date, such as {@code EPOCH_DAY}.
       * <p>
       * Not all {@code TemporalAccessor} implementations are accepted as return values.
       * Implementations that call this method must accept {@code ChronoLocalDate},
       * {@code ChronoLocalDateTime}, {@code ChronoZonedDateTime} and {@code LocalTime}.
       * <p>
       * The default implementation must return null.
       *
       * @param fieldValues  the map of fields to values, which can be updated, not null
       * @param partialTemporal  the partially complete temporal to query for zone and
       *  chronology; querying for other things is undefined and not recommended, not null
       * @param resolverStyle  the requested type of resolve, not null
       * @return the resolved temporal object; null if resolving only
       *  changed the map, or no resolve occurred
       * @throws ArithmeticException if numeric overflow occurs
       * @throws DateTimeException if resolving results in an error. This must not be thrown
       *  by querying a field on the temporal without first checking if it is supported
       */
      default TemporalAccessor resolve(
              Map<TemporalField, Long> fieldValues,
              TemporalAccessor partialTemporal,
              ResolverStyle resolverStyle) {
          return null;
      }
  
      /**
       * Gets a descriptive name for the field.
       * <p>
       * The should be of the format 'BaseOfRange', such as 'MonthOfYear',
       * unless the field has a range of {@code FOREVER}, when only
       * the base unit is mentioned, such as 'Year' or 'Era'.
       *
       * @return the name of the field, not null
       */
      @Override
      String toString();
  
  
  }
  