/*
    *  Copyright 2001-2013 Stephen Colebourne
    *
    *  Licensed under the Apache License, Version 2.0 (the "License");
    *  you may not use this file except in compliance with the License.
    *  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  package org.joda.time;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  import java.util.Calendar;
  import java.util.Date;
  import java.util.GregorianCalendar;
  import java.util.HashSet;
  import java.util.Locale;
  import java.util.Set;
  import java.util.TimeZone;
  
  import org.joda.convert.FromString;
  import org.joda.convert.ToString;
  import org.joda.time.base.BaseLocal;
  import org.joda.time.chrono.ISOChronology;
  import org.joda.time.convert.ConverterManager;
  import org.joda.time.convert.PartialConverter;
  import org.joda.time.field.AbstractReadableInstantFieldProperty;
  import org.joda.time.field.FieldUtils;
  import org.joda.time.format.DateTimeFormat;
  import org.joda.time.format.DateTimeFormatter;
  import org.joda.time.format.ISODateTimeFormat;
  
  /**
   * LocalDate is an immutable datetime class representing a date
   * without a time zone.
   * <p>
   * LocalDate implements the {@link ReadablePartial} interface.
   * To do this, the interface methods focus on the key fields -
   * Year, MonthOfYear and DayOfMonth.
   * However, <b>all</b> date fields may in fact be queried.
   * <p>
   * LocalDate differs from DateMidnight in that this class does not
   * have a time zone and does not represent a single instant in time.
   * <p>
   * Calculations on LocalDate are performed using a {@link Chronology}.
   * This chronology will be set internally to be in the UTC time zone
   * for all calculations.
   *
   * <p>Each individual field can be queried in two ways:
   * <ul>
   * <li><code>getMonthOfYear()</code>
   * <li><code>monthOfYear().get()</code>
   * </ul>
   * The second technique also provides access to other useful methods on the
   * field:
   * <ul>
   * <li>numeric value
   * <li>text value
   * <li>short text value
   * <li>maximum/minimum values
   * <li>add/subtract
   * <li>set
   * <li>rounding
   * </ul>
   *
   * <p>
   * LocalDate is thread-safe and immutable, provided that the Chronology is as well.
   * All standard Chronology classes supplied are thread-safe and immutable.
   *
   * @author Stephen Colebourne
   * @since 1.3
   */
  public final class LocalDate
          extends BaseLocal
          implements ReadablePartial, Serializable {
  
      /** Serialization lock */
      private static final long serialVersionUID = -8775358157899L;
  
      /** The index of the year field in the field array */
      private static final int YEAR = 0;
      /** The index of the monthOfYear field in the field array */
      private static final int MONTH_OF_YEAR = 1;
      /** The index of the dayOfMonth field in the field array */
      private static final int DAY_OF_MONTH = 2;
      /** Set of known duration types. */
      private static final Set<DurationFieldType> DATE_DURATION_TYPES = new HashSet<DurationFieldType>();
      static {
          DATE_DURATION_TYPES.add(DurationFieldType.days());
          DATE_DURATION_TYPES.add(DurationFieldType.weeks());
         DATE_DURATION_TYPES.add(DurationFieldType.months());
         DATE_DURATION_TYPES.add(DurationFieldType.weekyears());
         DATE_DURATION_TYPES.add(DurationFieldType.years());
         DATE_DURATION_TYPES.add(DurationFieldType.centuries());
         // eras are supported, although the DurationField generally isn't
         DATE_DURATION_TYPES.add(DurationFieldType.eras());
     }
 
     /** The local millis from 1970-01-01T00:00:00 */
     private final long iLocalMillis;
     /** The chronology to use in UTC. */
     private final Chronology iChronology;
     /** The cached hash code. */
     private transient volatile int iHash;
 
     //-----------------------------------------------------------------------
     /**
      * Obtains a {@code LocalDate} set to the current system millisecond time
      * using <code>ISOChronology</code> in the default time zone.
      * 
      * @return the current date-time, not null
      * @since 2.0
      */
     public static LocalDate now() {
         return new LocalDate();
     }
 
     /**
      * Obtains a {@code LocalDate} set to the current system millisecond time
      * using <code>ISOChronology</code> in the specified time zone.
      *
      * @param zone  the time zone, not null
      * @return the current date-time, not null
      * @since 2.0
      */
     public static LocalDate now(DateTimeZone zone) {
         if (zone == null) {
             throw new NullPointerException("Zone must not be null");
         }
         return new LocalDate(zone);
     }
 
     /**
      * Obtains a {@code LocalDate} set to the current system millisecond time
      * using the specified chronology.
      *
      * @param chronology  the chronology, not null
      * @return the current date-time, not null
      * @since 2.0
      */
     public static LocalDate now(Chronology chronology) {
         if (chronology == null) {
             throw new NullPointerException("Chronology must not be null");
         }
         return new LocalDate(chronology);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Parses a {@code LocalDate} from the specified string.
      * <p>
      * This uses {@link ISODateTimeFormat#localDateParser()}.
      * 
      * @param str  the string to parse, not null
      * @since 2.0
      */
     @FromString
     public static LocalDate parse(String str) {
         return parse(str, ISODateTimeFormat.localDateParser());
     }
 
     /**
      * Parses a {@code LocalDate} from the specified string using a formatter.
      * 
      * @param str  the string to parse, not null
      * @param formatter  the formatter to use, not null
      * @since 2.0
      */
     public static LocalDate parse(String str, DateTimeFormatter formatter) {
         return formatter.parseLocalDate(str);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Constructs a LocalDate from a <code>java.util.Calendar</code>
      * using exactly the same field values.
      * <p>
      * Each field is queried from the Calendar and assigned to the LocalDate.
      * This is useful if you have been using the Calendar as a local date,
      * ignoring the zone.
      * <p>
      * One advantage of this method is that this method is unaffected if the
      * version of the time zone data differs between the JDK and Joda-Time.
      * That is because the local field values are transferred, calculated using
      * the JDK time zone data and without using the Joda-Time time zone data.
      * <p>
      * This factory method ignores the type of the calendar and always
      * creates a LocalDate with ISO chronology. It is expected that you
      * will only pass in instances of <code>GregorianCalendar</code> however
      * this is not validated.
      *
      * @param calendar  the Calendar to extract fields from, not null
      * @return the created local date, not null
      * @throws IllegalArgumentException if the calendar is null
      * @throws IllegalArgumentException if the date is invalid for the ISO chronology
      */
     public static LocalDate fromCalendarFields(Calendar calendar) {
         if (calendar == null) {
             throw new IllegalArgumentException("The calendar must not be null");
         }
         int era = calendar.get(Calendar.ERA);
         int yearOfEra = calendar.get(Calendar.YEAR);
         return new LocalDate(
             (era == GregorianCalendar.AD ? yearOfEra : 1 - yearOfEra),
             calendar.get(Calendar.MONTH) + 1,
             calendar.get(Calendar.DAY_OF_MONTH)
         );
     }
 
     /**
      * Constructs a LocalDate from a <code>java.util.Date</code>
      * using exactly the same field values.
      * <p>
      * Each field is queried from the Date and assigned to the LocalDate.
      * This is useful if you have been using the Date as a local date,
      * ignoring the zone.
      * <p>
      * One advantage of this method is that this method is unaffected if the
      * version of the time zone data differs between the JDK and Joda-Time.
      * That is because the local field values are transferred, calculated using
      * the JDK time zone data and without using the Joda-Time time zone data.
      * <p>
      * This factory method always creates a LocalDate with ISO chronology.
      *
      * @param date  the Date to extract fields from, not null
      * @return the created local date, not null
      * @throws IllegalArgumentException if the calendar is null
      * @throws IllegalArgumentException if the date is invalid for the ISO chronology
      */
     @SuppressWarnings("deprecation")
     public static LocalDate fromDateFields(Date date) {
         if (date == null) {
             throw new IllegalArgumentException("The date must not be null");
         }
         if (date.getTime() < 0) {
             // handle years in era BC
             GregorianCalendar cal = new GregorianCalendar();
             cal.setTime(date);
             return fromCalendarFields(cal);
         }
         return new LocalDate(
             date.getYear() + 1900,
             date.getMonth() + 1,
             date.getDate()
         );
     }
 
     //-----------------------------------------------------------------------
     /**
      * Constructs an instance set to the current local time evaluated using
      * ISO chronology in the default zone.
      * <p>
      * Once the constructor is completed, the zone is no longer used.
      * 
      * @see #now()
      */
     public LocalDate() {
         this(DateTimeUtils.currentTimeMillis(), ISOChronology.getInstance());
     }
 
     /**
      * Constructs an instance set to the current local time evaluated using
      * ISO chronology in the specified zone.
      * <p>
      * If the specified time zone is null, the default zone is used.
      * Once the constructor is completed, the zone is no longer used.
      *
      * @param zone  the time zone, null means default zone
      * @see #now(DateTimeZone)
      */
     public LocalDate(DateTimeZone zone) {
         this(DateTimeUtils.currentTimeMillis(), ISOChronology.getInstance(zone));
     }
 
     /**
      * Constructs an instance set to the current local time evaluated using
      * specified chronology.
      * <p>
      * If the chronology is null, ISO chronology in the default time zone is used.
      * Once the constructor is completed, the zone is no longer used.
      *
      * @param chronology  the chronology, null means ISOChronology in default zone
      * @see #now(Chronology)
      */
     public LocalDate(Chronology chronology) {
         this(DateTimeUtils.currentTimeMillis(), chronology);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Constructs an instance set to the local time defined by the specified
      * instant evaluated using ISO chronology in the default zone.
      * <p>
      * Once the constructor is completed, the zone is no longer used.
      *
      * @param instant  the milliseconds from 1970-01-01T00:00:00Z
      */
     public LocalDate(long instant) {
         this(instant, ISOChronology.getInstance());
     }
 
     /**
      * Constructs an instance set to the local time defined by the specified
      * instant evaluated using ISO chronology in the specified zone.
      * <p>
      * If the specified time zone is null, the default zone is used.
      * Once the constructor is completed, the zone is no longer used.
      *
      * @param instant  the milliseconds from 1970-01-01T00:00:00Z
      * @param zone  the time zone, null means default zone
      */
     public LocalDate(long instant, DateTimeZone zone) {
         this(instant, ISOChronology.getInstance(zone));
     }
 
     /**
      * Constructs an instance set to the local time defined by the specified
      * instant evaluated using the specified chronology.
      * <p>
      * If the chronology is null, ISO chronology in the default zone is used.
      * Once the constructor is completed, the zone is no longer used.
      *
      * @param instant  the milliseconds from 1970-01-01T00:00:00Z
      * @param chronology  the chronology, null means ISOChronology in default zone
      */
     public LocalDate(long instant, Chronology chronology) {
         chronology = DateTimeUtils.getChronology(chronology);
         
         long localMillis = chronology.getZone().getMillisKeepLocal(DateTimeZone.UTC, instant);
         chronology = chronology.withUTC();
         iLocalMillis = chronology.dayOfMonth().roundFloor(localMillis);
         iChronology = chronology;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Constructs an instance from an Object that represents a datetime.
      * The time zone will be retrieved from the object if possible,
      * otherwise the default time zone will be used.
      * <p>
      * If the object contains no chronology, <code>ISOChronology</code> is used.
      * Once the constructor is completed, the zone is no longer used.
      * <p>
      * The recognised object types are defined in
      * {@link org.joda.time.convert.ConverterManager ConverterManager} and
      * include ReadablePartial, ReadableInstant, String, Calendar and Date.
      * The String formats are described by {@link ISODateTimeFormat#localDateParser()}.
      * The default String converter ignores the zone and only parses the field values.
      *
      * @param instant  the datetime object
      * @throws IllegalArgumentException if the instant is invalid
      */
     public LocalDate(Object instant) {
         this(instant, (Chronology) null);
     }
 
     /**
      * Constructs an instance from an Object that represents a datetime,
      * forcing the time zone to that specified.
      * <p>
      * If the object contains no chronology, <code>ISOChronology</code> is used.
      * If the specified time zone is null, the default zone is used.
      * Once the constructor is completed, the zone is no longer used.
      * <p>
      * The recognised object types are defined in
      * {@link org.joda.time.convert.ConverterManager ConverterManager} and
      * include ReadablePartial, ReadableInstant, String, Calendar and Date.
      * The String formats are described by {@link ISODateTimeFormat#localDateParser()}.
      * The default String converter ignores the zone and only parses the field values.
      *
      * @param instant  the datetime object
      * @param zone  the time zone
      * @throws IllegalArgumentException if the instant is invalid
      */
     public LocalDate(Object instant, DateTimeZone zone) {
         PartialConverter converter = ConverterManager.getInstance().getPartialConverter(instant);
         Chronology chronology = converter.getChronology(instant, zone);
         chronology = DateTimeUtils.getChronology(chronology);
         iChronology = chronology.withUTC();
         int[] values = converter.getPartialValues(this, instant, chronology, ISODateTimeFormat.localDateParser());
         iLocalMillis = iChronology.getDateTimeMillis(values[0], values[1], values[2], 0);
     }
 
     /**
      * Constructs an instance from an Object that represents a datetime,
      * using the specified chronology.
      * <p>
      * If the chronology is null, ISO in the default time zone is used.
      * Once the constructor is completed, the zone is no longer used.
      * If the instant contains a chronology, it will be ignored.
      * For example, passing a {@code LocalDate} and a different chronology
      * will return a date with the year/month/day from the date applied
      * unaltered to the specified chronology.
      * <p>
      * The recognised object types are defined in
      * {@link org.joda.time.convert.ConverterManager ConverterManager} and
      * include ReadablePartial, ReadableInstant, String, Calendar and Date.
      * The String formats are described by {@link ISODateTimeFormat#localDateParser()}.
      * The default String converter ignores the zone and only parses the field values.
      *
      * @param instant  the datetime object
      * @param chronology  the chronology
      * @throws IllegalArgumentException if the instant is invalid
      */
     public LocalDate(Object instant, Chronology chronology) {
         PartialConverter converter = ConverterManager.getInstance().getPartialConverter(instant);
         chronology = converter.getChronology(instant, chronology);
         chronology = DateTimeUtils.getChronology(chronology);
         iChronology = chronology.withUTC();
         int[] values = converter.getPartialValues(this, instant, chronology, ISODateTimeFormat.localDateParser());
         iLocalMillis = iChronology.getDateTimeMillis(values[0], values[1], values[2], 0);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Constructs an instance set to the specified date and time
      * using <code>ISOChronology</code>.
      *
      * @param year  the year
      * @param monthOfYear  the month of the year, from 1 to 12
      * @param dayOfMonth  the day of the month, from 1 to 31
      */
     public LocalDate(
             int year,
             int monthOfYear,
             int dayOfMonth) {
         this(year, monthOfYear, dayOfMonth, ISOChronology.getInstanceUTC());
     }
 
     /**
      * Constructs an instance set to the specified date and time
      * using the specified chronology, whose zone is ignored.
      * <p>
      * If the chronology is null, <code>ISOChronology</code> is used.
      *
      * @param year  the year, valid values defined by the chronology
      * @param monthOfYear  the month of the year, valid values defined by the chronology
      * @param dayOfMonth  the day of the month, valid values defined by the chronology
      * @param chronology  the chronology, null means ISOChronology in default zone
      */
     public LocalDate(
             int year,
             int monthOfYear,
             int dayOfMonth,
             Chronology chronology) {
         super();
         chronology = DateTimeUtils.getChronology(chronology).withUTC();
         long instant = chronology.getDateTimeMillis(year, monthOfYear, dayOfMonth, 0);
         iChronology = chronology;
         iLocalMillis = instant;
     }
 
     /**
      * Handle broken serialization from other tools.
      * @return the resolved object, not null
      */
     private Object readResolve() {
         if (iChronology == null) {
             return new LocalDate(iLocalMillis, ISOChronology.getInstanceUTC());
         }
         if (DateTimeZone.UTC.equals(iChronology.getZone()) == false) {
             return new LocalDate(iLocalMillis, iChronology.withUTC());
         }
         return this;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Gets the number of fields in this partial, which is three.
      * The supported fields are Year, MonthOfYear and DayOfMonth.
      * Note that all fields from day and above may in fact be queried via
      * other methods.
      *
      * @return the field count, three
      */
     public int size() {
         return 3;
     }
 
     /**
      * Gets the field for a specific index in the chronology specified.
      * <p>
      * This method must not use any instance variables.
      *
      * @param index  the index to retrieve
      * @param chrono  the chronology to use
      * @return the field
      */
     protected DateTimeField getField(int index, Chronology chrono) {
         switch (index) {
             case YEAR:
                 return chrono.year();
             case MONTH_OF_YEAR:
                 return chrono.monthOfYear();
             case DAY_OF_MONTH:
                 return chrono.dayOfMonth();
             default:
                 throw new IndexOutOfBoundsException("Invalid index: " + index);
         }
     }
 
     /**
      * Gets the value of the field at the specifed index.
      * <p>
      * This method is required to support the <code>ReadablePartial</code>
      * interface. The supported fields are Year, MonthOfYear and DayOfMonth.
      * Note that all fields from day and above may in fact be queried via
      * other methods.
      *
      * @param index  the index, zero to two
      * @return the value
      * @throws IndexOutOfBoundsException if the index is invalid
      */
     public int getValue(int index) {
         switch (index) {
             case YEAR:
                 return getChronology().year().get(getLocalMillis());
             case MONTH_OF_YEAR:
                 return getChronology().monthOfYear().get(getLocalMillis());
             case DAY_OF_MONTH:
                 return getChronology().dayOfMonth().get(getLocalMillis());
             default:
                 throw new IndexOutOfBoundsException("Invalid index: " + index);
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Get the value of one of the fields of a datetime.
      * <p>
      * This method gets the value of the specified field.
      * For example:
      * <pre>
      * LocalDate dt = LocalDate.nowDefaultZone();
      * int year = dt.get(DateTimeFieldType.year());
      * </pre>
      *
      * @param fieldType  a field type, usually obtained from DateTimeFieldType, not null
      * @return the value of that field
      * @throws IllegalArgumentException if the field type is null or unsupported
      */
     public int get(DateTimeFieldType fieldType) {
         if (fieldType == null) {
             throw new IllegalArgumentException("The DateTimeFieldType must not be null");
         }
         if (isSupported(fieldType) == false) {
             throw new IllegalArgumentException("Field '" + fieldType + "' is not supported");
         }
         return fieldType.getField(getChronology()).get(getLocalMillis());
     }
 
     /**
      * Checks if the field type specified is supported by this
      * local date and chronology.
      * This can be used to avoid exceptions in {@link #get(DateTimeFieldType)}.
      *
      * @param type  a field type, usually obtained from DateTimeFieldType
      * @return true if the field type is supported
      */
     public boolean isSupported(DateTimeFieldType type) {
         if (type == null) {
             return false;
         }
         DurationFieldType durType = type.getDurationType();
         if (DATE_DURATION_TYPES.contains(durType) ||
                 durType.getField(getChronology()).getUnitMillis() >=
                     getChronology().days().getUnitMillis()) {
             return type.getField(getChronology()).isSupported();
         }
         return false;
     }
 
     /**
      * Checks if the duration type specified is supported by this
      * local date and chronology.
      *
      * @param type  a duration type, usually obtained from DurationFieldType
      * @return true if the field type is supported
      */
     public boolean isSupported(DurationFieldType type) {
         if (type == null) {
             return false;
         }
         DurationField field = type.getField(getChronology());
         if (DATE_DURATION_TYPES.contains(type) ||
             field.getUnitMillis() >= getChronology().days().getUnitMillis()) {
             return field.isSupported();
         }
         return false;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Gets the local milliseconds from the Java epoch
      * of 1970-01-01T00:00:00 (not fixed to any specific time zone).
      * 
      * @return the number of milliseconds since 1970-01-01T00:00:00
      * @since 1.5 (previously private)
      */
     protected long getLocalMillis() {
         return iLocalMillis;
     }
 
     /**
      * Gets the chronology of the date.
      * 
      * @return the Chronology that the date is using
      */
     public Chronology getChronology() {
         return iChronology;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Compares this ReadablePartial with another returning true if the chronology,
      * field types and values are equal.
      *
      * @param partial  an object to check against
      * @return true if fields and values are equal
      */
     public boolean equals(Object partial) {
         // override to perform faster
         if (this == partial) {
             return true;
         }
         if (partial instanceof LocalDate) {
             LocalDate other = (LocalDate) partial;
             if (iChronology.equals(other.iChronology)) {
                 return iLocalMillis == other.iLocalMillis;
             }
         }
         return super.equals(partial);
     }
 
     /**
      * Gets a hash code for the instant as defined in <code>ReadablePartial</code>.
      *
      * @return a suitable hash code
      */
     public int hashCode() {
         // override for performance
         int hash = iHash;
         if (hash == 0) {
             hash = iHash = super.hashCode();
         }
         return hash;
     }
 
     /**
      * Compares this partial with another returning an integer
      * indicating the order.
      * <p>
      * The fields are compared in order, from largest to smallest.
      * The first field that is non-equal is used to determine the result.
      * <p>
      * The specified object must be a partial instance whose field types
      * match those of this partial.
      *
      * @param partial  an object to check against
      * @return negative if this is less, zero if equal, positive if greater
      * @throws ClassCastException if the partial is the wrong class
      *  or if it has field types that don't match
      * @throws NullPointerException if the partial is null
      */
     public int compareTo(ReadablePartial partial) {
         // override to perform faster
         if (this == partial) {
             return 0;
         }
         if (partial instanceof LocalDate) {
             LocalDate other = (LocalDate) partial;
             if (iChronology.equals(other.iChronology)) {
                 return (iLocalMillis < other.iLocalMillis ? -1 :
                             (iLocalMillis == other.iLocalMillis ? 0 : 1));
 
             }
         }
         return super.compareTo(partial);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this LocalDate to a full datetime at the earliest valid time
      * for the date using the default time zone.
      * <p>
      * The time will normally be midnight, as that is the earliest time on
      * any given day. However, in some time zones when Daylight Savings Time
      * starts, there is no midnight because time jumps from 11:59 to 01:00.
      * This method handles that situation by returning 01:00 on that date.
      * <p>
      * This instance is immutable and unaffected by this method call.
      * 
      * @return this date as a datetime at the start of the day
      * @since 1.5
      */
     public DateTime toDateTimeAtStartOfDay() {
         return toDateTimeAtStartOfDay(null);
     }
 
     /**
      * Converts this LocalDate to a full datetime at the earliest valid time
      * for the date using the specified time zone.
      * <p>
      * The time will normally be midnight, as that is the earliest time on
      * any given day. However, in some time zones when Daylight Savings Time
      * starts, there is no midnight because time jumps from 11:59 to 01:00.
      * This method handles that situation by returning 01:00 on that date.
      * <p>
      * This method uses the chronology from this instance plus the time zone
      * specified.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param zone  the zone to use, null means default zone
      * @return this date as a datetime at the start of the day
      * @since 1.5
      */
     public DateTime toDateTimeAtStartOfDay(DateTimeZone zone) {
         zone = DateTimeUtils.getZone(zone);
         Chronology chrono = getChronology().withZone(zone);
         long localMillis = getLocalMillis() + 6L * DateTimeConstants.MILLIS_PER_HOUR;
         long instant = zone.convertLocalToUTC(localMillis, false);
         instant = chrono.dayOfMonth().roundFloor(instant);
         return new DateTime(instant, chrono);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this LocalDate to a full datetime at midnight using the default
      * time zone.
      * <p>
      * This method will throw an exception if the default time zone switches
      * to Daylight Savings Time at midnight and this LocalDate represents
      * that switchover date. The problem is that there is no such time as
      * midnight on the required date, and as such an exception is thrown.
      * <p>
      * This instance is immutable and unaffected by this method call.
      * 
      * @return this date as a datetime at midnight
      * @deprecated Use {@link #toDateTimeAtStartOfDay()} which won't throw an exception
      */
     @Deprecated
     public DateTime toDateTimeAtMidnight() {
         return toDateTimeAtMidnight(null);
     }
 
     /**
      * Converts this LocalDate to a full datetime at midnight using the
      * specified time zone.
      * <p>
      * This method will throw an exception if the time zone switches
      * to Daylight Savings Time at midnight and this LocalDate represents
      * that switchover date. The problem is that there is no such time as
      * midnight on the required date, and as such an exception is thrown.
      * <p>
      * This method uses the chronology from this instance plus the time zone
      * specified.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param zone  the zone to use, null means default zone
      * @return this date as a datetime at midnight
      * @deprecated Use {@link #toDateTimeAtStartOfDay(DateTimeZone)} which won't throw an exception
      */
     @Deprecated
     public DateTime toDateTimeAtMidnight(DateTimeZone zone) {
         zone = DateTimeUtils.getZone(zone);
         Chronology chrono = getChronology().withZone(zone);
         return new DateTime(getYear(), getMonthOfYear(), getDayOfMonth(), 0, 0, 0, 0, chrono);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this LocalDate to a full datetime using the default time zone
      * setting the date fields from this instance and the time fields from
      * the current time.
      * <p>
      * This method will throw an exception if the datetime that would be
      * created does not exist when the time zone is taken into account.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @return this date as a datetime with the time as the current time
      */
     public DateTime toDateTimeAtCurrentTime() {
         return toDateTimeAtCurrentTime(null);
     }
 
     /**
      * Converts this LocalDate to a full datetime using the specified time zone
      * setting the date fields from this instance and the time fields from
      * the current time.
      * <p>
      * This method uses the chronology from this instance plus the time zone
      * specified.
      * <p>
      * This method will throw an exception if the datetime that would be
      * created does not exist when the time zone is taken into account.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param zone  the zone to use, null means default zone
      * @return this date as a datetime with the time as the current time
      */
     public DateTime toDateTimeAtCurrentTime(DateTimeZone zone) {
         zone = DateTimeUtils.getZone(zone);
         Chronology chrono = getChronology().withZone(zone);
         long instantMillis = DateTimeUtils.currentTimeMillis();
         long resolved = chrono.set(this, instantMillis);
         return new DateTime(resolved, chrono);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this LocalDate to a DateMidnight in the default time zone.
      * <p>
      * As from v1.5, you are recommended to avoid DateMidnight and use
      * {@link #toDateTimeAtStartOfDay()} instead because of the exception
      * detailed below.
      * <p>
      * This method will throw an exception if the default time zone switches
      * to Daylight Savings Time at midnight and this LocalDate represents
      * that switchover date. The problem is that there is no such time as
      * midnight on the required date, and as such an exception is thrown.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @return the DateMidnight instance in the default zone
      */
     public DateMidnight toDateMidnight() {
         return toDateMidnight(null);
     }
 
     /**
      * Converts this LocalDate to a DateMidnight.
      * <p>
      * As from v1.5, you are recommended to avoid DateMidnight and use
      * {@link #toDateTimeAtStartOfDay()} instead because of the exception
      * detailed below.
      * <p>
      * This method will throw an exception if the time zone switches
      * to Daylight Savings Time at midnight and this LocalDate represents
      * that switchover date. The problem is that there is no such time as
      * midnight on the required date, and as such an exception is thrown.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param zone  the zone to get the DateMidnight in, null means default zone
      * @return the DateMidnight instance
      */
     public DateMidnight toDateMidnight(DateTimeZone zone) {
         zone = DateTimeUtils.getZone(zone);
         Chronology chrono = getChronology().withZone(zone);
         return new DateMidnight(getYear(), getMonthOfYear(), getDayOfMonth(), chrono);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this object to a LocalDateTime using a LocalTime to fill in
      * the missing fields.
      * <p>
      * The resulting chronology is determined by the chronology of this
      * LocalDate. The chronology of the time must also match.
      * If the time is null an exception is thrown.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param time  the time of day to use, must not be null
      * @return the LocalDateTime instance
      * @throws IllegalArgumentException if the time is null
      * @throws IllegalArgumentException if the chronology of the time does not match
      * @since 1.5
      */
     public LocalDateTime toLocalDateTime(LocalTime time) {
         if (time == null) {
             throw new IllegalArgumentException("The time must not be null");
         }
         if (getChronology() != time.getChronology()) {
             throw new IllegalArgumentException("The chronology of the time does not match");
         }
         long localMillis = getLocalMillis() + time.getLocalMillis();
         return new LocalDateTime(localMillis, getChronology());
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this object to a DateTime using a LocalTime to fill in the
      * missing fields and using the default time zone.
      * <p>
      * The resulting chronology is determined by the chronology of this
      * LocalDate. The chronology of the time must match.
      * If the time is null, the current time in the date's chronology is used.
      * <p>
      * This method will throw an exception if the datetime that would be
      * created does not exist when the time zone is taken into account.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param time  the time of day to use, null means current time
      * @return the DateTime instance
      * @throws IllegalArgumentException if the chronology of the time does not match
      */
     public DateTime toDateTime(LocalTime time) {
         return toDateTime(time, null);
     }
 
     /**
      * Converts this object to a DateTime using a LocalTime to fill in the
      * missing fields.
      * <p>
      * The resulting chronology is determined by the chronology of this
      * LocalDate plus the time zone. The chronology of the time must match.
      * If the time is null, the current time in the date's chronology is used.
      * <p>
      * This method will throw an exception if the datetime that would be
      * created does not exist when the time zone is taken into account.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param time  the time of day to use, null means current time
      * @param zone  the zone to get the DateTime in, null means default
      * @return the DateTime instance
      * @throws IllegalArgumentException if the chronology of the time does not match
      */
     public DateTime toDateTime(LocalTime time, DateTimeZone zone) {
         if (time != null && getChronology() != time.getChronology()) {
             throw new IllegalArgumentException("The chronology of the time does not match");
         }
         Chronology chrono = getChronology().withZone(zone);
         long instant = DateTimeUtils.currentTimeMillis();
         instant = chrono.set(this, instant);
         if (time != null) {
             instant = chrono.set(time, instant);
         }
         return new DateTime(instant, chrono);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts this object to an Interval representing the whole day
      * in the default time zone.
      * <p>
      * The interval may have more or less than 24 hours if this is a daylight
      * savings cutover date.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @return a interval over the day
      */
     public Interval toInterval() {
         return toInterval(null);
     }
 
     /**
      * Converts this object to an Interval representing the whole day.
      * <p>
      * The interval may have more or less than 24 hours if this is a daylight
      * savings cutover date.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param zone  the zone to get the Interval in, null means default
      * @return a interval over the day
      */
     public Interval toInterval(DateTimeZone zone) {
         zone = DateTimeUtils.getZone(zone);
         DateTime start = toDateTimeAtStartOfDay(zone);
         DateTime end = plusDays(1).toDateTimeAtStartOfDay(zone);
         return new Interval(start, end);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Get the date time as a <code>java.util.Date</code>.
      * <p>
      * The <code>Date</code> object created has exactly the same year, month and day
      * as this date. The time will be set to the earliest valid time for that date.
      * <p>
      * Converting to a JDK Date is full of complications as the JDK Date constructor
      * doesn't behave as you might expect around DST transitions. This method works
      * by taking a first guess and then adjusting the JDK date until it has the
      * earliest valid instant. This also handles the situation where the JDK time
      * zone data differs from the Joda-Time time zone data.
      *
      * @return a Date initialised with this date, never null
      * @since 2.0
      */
     @SuppressWarnings("deprecation")
     public Date toDate() {
         int dom = getDayOfMonth();
         Date date = new Date(getYear() - 1900, getMonthOfYear() - 1, dom);
         LocalDate check = LocalDate.fromDateFields(date);
         if (check.isBefore(this)) {
             // DST gap (no midnight)
             // move forward in units of one hour until date correct
             while (check.equals(this) == false) {
                 date.setTime(date.getTime() + 3600000);
                 check = LocalDate.fromDateFields(date);
             }
             // move back in units of one second until date wrong
             while (date.getDate() == dom) {
                 date.setTime(date.getTime() - 1000);
             }
             // fix result
             date.setTime(date.getTime() + 1000);
         } else if (check.equals(this)) {
             // check for DST overlap (two midnights)
             Date earlier = new Date(date.getTime() - TimeZone.getDefault().getDSTSavings());
             if (earlier.getDate() == dom) {
                 date = earlier;
             }
         }
         return date;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date with different local millis.
      * <p>
      * The returned object will be a new instance of the same type.
      * Only the millis will change, the chronology is kept.
      * The returned object will be either be a new instance or <code>this</code>.
      *
      * @param newMillis  the new millis, from 1970-01-01T00:00:00
      * @return a copy of this date with different millis
      */
     LocalDate withLocalMillis(long newMillis) {
         newMillis = iChronology.dayOfMonth().roundFloor(newMillis);
         return (newMillis == getLocalMillis() ? this : new LocalDate(newMillis, getChronology()));
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date with the partial set of fields replacing
      * those from this instance.
      * <p>
      * For example, if the partial contains a year and a month then those two
      * fields will be changed in the returned instance.
      * Unsupported fields are ignored.
      * If the partial is null, then <code>this</code> is returned.
      *
      * @param partial  the partial set of fields to apply to this date, null ignored
      * @return a copy of this date with a different set of fields
      * @throws IllegalArgumentException if any value is invalid
      */
     public LocalDate withFields(ReadablePartial partial) {
         if (partial == null) {
             return this;
         }
         return withLocalMillis(getChronology().set(partial, getLocalMillis()));
     }
 
     /**
      * Returns a copy of this date with the specified field set to a new value.
      * <p>
      * For example, if the field type is <code>monthOfYear</code> then the
      * month of year field will be changed in the returned instance.
      * If the field type is null, then <code>this</code> is returned.
      * <p>
      * These two lines are equivalent:
      * <pre>
      * LocalDate updated = dt.withDayOfMonth(6);
      * LocalDate updated = dt.withField(DateTimeFieldType.dayOfMonth(), 6);
      * </pre>
      *
      * @param fieldType  the field type to set, not null
      * @param value  the value to set
      * @return a copy of this date with the field set
      * @throws IllegalArgumentException if the field is null or unsupported
      */
     public LocalDate withField(DateTimeFieldType fieldType, int value) {
         if (fieldType == null) {
             throw new IllegalArgumentException("Field must not be null");
         }
         if (isSupported(fieldType) == false) {
             throw new IllegalArgumentException("Field '" + fieldType + "' is not supported");
         }
         long instant = fieldType.getField(getChronology()).set(getLocalMillis(), value);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date with the value of the specified field increased.
      * <p>
      * If the addition is zero or the field is null, then <code>this</code> is returned.
      * <p>
      * These three lines are equivalent:
      * <pre>
      * LocalDate added = dt.withFieldAdded(DurationFieldType.years(), 6);
      * LocalDate added = dt.plusYears(6);
      * LocalDate added = dt.plus(Period.years(6));
      * </pre>
      *
      * @param fieldType  the field type to add to, not null
      * @param amount  the amount to add
      * @return a copy of this date with the field updated
      * @throws IllegalArgumentException if the field is null or unsupported
      * @throws ArithmeticException if the result exceeds the internal capacity
      */
     public LocalDate withFieldAdded(DurationFieldType fieldType, int amount) {
         if (fieldType == null) {
             throw new IllegalArgumentException("Field must not be null");
         }
         if (isSupported(fieldType) == false) {
             throw new IllegalArgumentException("Field '" + fieldType + "' is not supported");
         }
         if (amount == 0) {
             return this;
         }
         long instant = fieldType.getField(getChronology()).add(getLocalMillis(), amount);
         return withLocalMillis(instant);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date with the specified period added.
      * <p>
      * If the addition is zero, then <code>this</code> is returned.
      * <p>
      * This method is typically used to add multiple copies of complex
      * period instances. Adding one field is best achieved using methods
      * like {@link #withFieldAdded(DurationFieldType, int)}
      * or {@link #plusYears(int)}.
      * <p>
      * Unsupported time fields are ignored, thus adding a period of 24 hours
      * will not have any effect.
      *
      * @param period  the period to add to this one, null means zero
      * @param scalar  the amount of times to add, such as -1 to subtract once
      * @return a copy of this date with the period added
      * @throws ArithmeticException if the result exceeds the internal capacity
      */
     public LocalDate withPeriodAdded(ReadablePeriod period, int scalar) {
         if (period == null || scalar == 0) {
             return this;
         }
         long instant = getLocalMillis();
         Chronology chrono = getChronology();
         for (int i = 0; i < period.size(); i++) {
             long value = FieldUtils.safeMultiply(period.getValue(i), scalar);
             DurationFieldType type = period.getFieldType(i);
             if (isSupported(type)) {
                 instant = type.getField(chrono).add(instant, value);
             }
         }
         return withLocalMillis(instant);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date with the specified period added.
      * <p>
      * If the amount is zero or null, then <code>this</code> is returned.
      * <p>
      * This method is typically used to add complex period instances.
      * Adding one field is best achieved using methods
      * like {@link #plusYears(int)}.
      * <p>
      * Unsupported time fields are ignored, thus adding a period of 24 hours
      * will not have any effect.
      *
      * @param period  the period to add to this one, null means zero
      * @return a copy of this date with the period added
      * @throws ArithmeticException if the result exceeds the internal capacity
      */
     public LocalDate plus(ReadablePeriod period) {
         return withPeriodAdded(period, 1);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date plus the specified number of years.
      * <p>
      * This adds the specified number of years to the date.
      * If adding years makes the day-of-month invalid, it is adjusted to the last valid day in the month.
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate added = dt.plusYears(6);
      * LocalDate added = dt.plus(Period.years(6));
      * LocalDate added = dt.withFieldAdded(DurationFieldType.years(), 6);
      * </pre>
      *
      * @param years  the amount of years to add, may be negative
      * @return the new LocalDate plus the increased years
      */
     public LocalDate plusYears(int years) {
         if (years == 0) {
             return this;
         }
         long instant = getChronology().years().add(getLocalMillis(), years);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date plus the specified number of months.
      * <p>
      * This adds the specified number of months to the date.
      * The addition may change the year, but the day-of-month is normally unchanged.
      * If adding months makes the day-of-month invalid, it is adjusted to the last valid day in the month.
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate added = dt.plusMonths(6);
      * LocalDate added = dt.plus(Period.months(6));
      * LocalDate added = dt.withFieldAdded(DurationFieldType.months(), 6);
      * </pre>
      *
      * @param months  the amount of months to add, may be negative
      * @return the new LocalDate plus the increased months
      */
     public LocalDate plusMonths(int months) {
         if (months == 0) {
             return this;
         }
         long instant = getChronology().months().add(getLocalMillis(), months);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date plus the specified number of weeks.
      * <p>
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate added = dt.plusWeeks(6);
      * LocalDate added = dt.plus(Period.weeks(6));
      * LocalDate added = dt.withFieldAdded(DurationFieldType.weeks(), 6);
      * </pre>
      *
      * @param weeks  the amount of weeks to add, may be negative
      * @return the new LocalDate plus the increased weeks
      */
     public LocalDate plusWeeks(int weeks) {
         if (weeks == 0) {
             return this;
         }
         long instant = getChronology().weeks().add(getLocalMillis(), weeks);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date plus the specified number of days.
      * <p>
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate added = dt.plusDays(6);
      * LocalDate added = dt.plus(Period.days(6));
      * LocalDate added = dt.withFieldAdded(DurationFieldType.days(), 6);
      * </pre>
      *
      * @param days  the amount of days to add, may be negative
      * @return the new LocalDate plus the increased days
      */
     public LocalDate plusDays(int days) {
         if (days == 0) {
             return this;
         }
         long instant = getChronology().days().add(getLocalMillis(), days);
         return withLocalMillis(instant);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date with the specified period taken away.
      * <p>
      * If the amount is zero or null, then <code>this</code> is returned.
      * <p>
      * This method is typically used to subtract complex period instances.
      * Subtracting one field is best achieved using methods
      * like {@link #minusYears(int)}.
      * <p>
      * Unsupported time fields are ignored, thus subtracting a period of 24 hours
      * will not have any effect.
      *
      * @param period  the period to reduce this instant by
      * @return a copy of this LocalDate with the period taken away
      * @throws ArithmeticException if the result exceeds the internal capacity
      */
     public LocalDate minus(ReadablePeriod period) {
         return withPeriodAdded(period, -1);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date minus the specified number of years.
      * <p>
      * This subtracts the specified number of years from the date.
      * If subtracting years makes the day-of-month invalid, it is adjusted to the last valid day in the month.
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate subtracted = dt.minusYears(6);
      * LocalDate subtracted = dt.minus(Period.years(6));
      * LocalDate subtracted = dt.withFieldAdded(DurationFieldType.years(), -6);
      * </pre>
      *
      * @param years  the amount of years to subtract, may be negative
      * @return the new LocalDate minus the increased years
      */
     public LocalDate minusYears(int years) {
         if (years == 0) {
             return this;
         }
         long instant = getChronology().years().subtract(getLocalMillis(), years);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date minus the specified number of months.
      * <p>
      * This subtracts the specified number of months from the date.
      * The subtraction may change the year, but the day-of-month is normally unchanged.
      * If subtracting months makes the day-of-month invalid, it is adjusted to the last valid day in the month.
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate subtracted = dt.minusMonths(6);
      * LocalDate subtracted = dt.minus(Period.months(6));
      * LocalDate subtracted = dt.withFieldAdded(DurationFieldType.months(), -6);
      * </pre>
      *
      * @param months  the amount of months to subtract, may be negative
      * @return the new LocalDate minus the increased months
      */
     public LocalDate minusMonths(int months) {
         if (months == 0) {
             return this;
         }
         long instant = getChronology().months().subtract(getLocalMillis(), months);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date minus the specified number of weeks.
      * <p>
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate subtracted = dt.minusWeeks(6);
      * LocalDate subtracted = dt.minus(Period.weeks(6));
      * LocalDate subtracted = dt.withFieldAdded(DurationFieldType.weeks(), -6);
      * </pre>
      *
      * @param weeks  the amount of weeks to subtract, may be negative
      * @return the new LocalDate minus the increased weeks
      */
     public LocalDate minusWeeks(int weeks) {
         if (weeks == 0) {
             return this;
         }
         long instant = getChronology().weeks().subtract(getLocalMillis(), weeks);
         return withLocalMillis(instant);
     }
 
     /**
      * Returns a copy of this date minus the specified number of days.
      * <p>
      * This LocalDate instance is immutable and unaffected by this method call.
      * <p>
      * The following three lines are identical in effect:
      * <pre>
      * LocalDate subtracted = dt.minusDays(6);
      * LocalDate subtracted = dt.minus(Period.days(6));
      * LocalDate subtracted = dt.withFieldAdded(DurationFieldType.days(), -6);
      * </pre>
      *
      * @param days  the amount of days to subtract, may be negative
      * @return the new LocalDate minus the increased days
      */
     public LocalDate minusDays(int days) {
         if (days == 0) {
             return this;
         }
         long instant = getChronology().days().subtract(getLocalMillis(), days);
         return withLocalMillis(instant);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Gets the property object for the specified type, which contains many
      * useful methods.
      *
      * @param fieldType  the field type to get the chronology for
      * @return the property object
      * @throws IllegalArgumentException if the field is null or unsupported
      */
     public Property property(DateTimeFieldType fieldType) {
         if (fieldType == null) {
             throw new IllegalArgumentException("The DateTimeFieldType must not be null");
         }
         if (isSupported(fieldType) == false) {
             throw new IllegalArgumentException("Field '" + fieldType + "' is not supported");
         }
         return new Property(this, fieldType.getField(getChronology()));
     }
 
     //-----------------------------------------------------------------------
     /**
      * Get the era field value.
      *
      * @return the era
      */
     public int getEra() {
         return getChronology().era().get(getLocalMillis());
     }
 
     /**
      * Get the year of era field value.
      *
      * @return the year of era
      */
     public int getCenturyOfEra() {
         return getChronology().centuryOfEra().get(getLocalMillis());
     }
 
     /**
      * Get the year of era field value.
      *
      * @return the year of era
      */
     public int getYearOfEra() {
         return getChronology().yearOfEra().get(getLocalMillis());
     }
 
     /**
      * Get the year of century field value.
      *
      * @return the year of century
      */
     public int getYearOfCentury() {
         return getChronology().yearOfCentury().get(getLocalMillis());
     }
 
     /**
      * Get the year field value.
      *
      * @return the year
      */
     public int getYear() {
         return getChronology().year().get(getLocalMillis());
     }
 
     /**
      * Get the weekyear field value.
      * <p>
      * The weekyear is the year that matches with the weekOfWeekyear field.
      * In the standard ISO8601 week algorithm, the first week of the year
      * is that in which at least 4 days are in the year. As a result of this
      * definition, day 1 of the first week may be in the previous year.
      * The weekyear allows you to query the effective year for that day.
      *
      * @return the weekyear
      */
     public int getWeekyear() {
         return getChronology().weekyear().get(getLocalMillis());
     }
 
     /**
      * Get the month of year field value.
      *
      * @return the month of year
      */
     public int getMonthOfYear() {
         return getChronology().monthOfYear().get(getLocalMillis());
     }
 
     /**
      * Get the week of weekyear field value.
      * <p>
      * This field is associated with the "weekyear" via {@link #getWeekyear()}.
      * In the standard ISO8601 week algorithm, the first week of the year
      * is that in which at least 4 days are in the year. As a result of this
      * definition, day 1 of the first week may be in the previous year.
      *
      * @return the week of a week based year
      */
     public int getWeekOfWeekyear() {
         return getChronology().weekOfWeekyear().get(getLocalMillis());
     }
 
     /**
      * Get the day of year field value.
      *
      * @return the day of year
      */
     public int getDayOfYear() {
         return getChronology().dayOfYear().get(getLocalMillis());
     }
 
     /**
      * Get the day of month field value.
      * <p>
      * The values for the day of month are defined in {@link org.joda.time.DateTimeConstants}.
      *
      * @return the day of month
      */
     public int getDayOfMonth() {
         return getChronology().dayOfMonth().get(getLocalMillis());
     }
 
     /**
      * Get the day of week field value.
      * <p>
      * The values for the day of week are defined in {@link org.joda.time.DateTimeConstants}.
      *
      * @return the day of week
      */
     public int getDayOfWeek() {
         return getChronology().dayOfWeek().get(getLocalMillis());
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a copy of this date with the era field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * era changed.
      *
      * @param era  the era to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withEra(int era) {
         return withLocalMillis(getChronology().era().set(getLocalMillis(), era));
     }
 
     /**
      * Returns a copy of this date with the century of era field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * century of era changed.
      *
      * @param centuryOfEra  the centurey of era to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withCenturyOfEra(int centuryOfEra) {
         return withLocalMillis(getChronology().centuryOfEra().set(getLocalMillis(), centuryOfEra));
     }
 
     /**
      * Returns a copy of this date with the year of era field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * year of era changed.
      *
      * @param yearOfEra  the year of era to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withYearOfEra(int yearOfEra) {
         return withLocalMillis(getChronology().yearOfEra().set(getLocalMillis(), yearOfEra));
     }
 
     /**
      * Returns a copy of this date with the year of century field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * year of century changed.
      *
      * @param yearOfCentury  the year of century to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withYearOfCentury(int yearOfCentury) {
         return withLocalMillis(getChronology().yearOfCentury().set(getLocalMillis(), yearOfCentury));
     }
 
     /**
      * Returns a copy of this date with the year field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * year changed.
      *
      * @param year  the year to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withYear(int year) {
         return withLocalMillis(getChronology().year().set(getLocalMillis(), year));
     }
 
     /**
      * Returns a copy of this date with the weekyear field updated.
      * <p>
      * The weekyear is the year that matches with the weekOfWeekyear field.
      * In the standard ISO8601 week algorithm, the first week of the year
      * is that in which at least 4 days are in the year. As a result of this
      * definition, day 1 of the first week may be in the previous year.
      * The weekyear allows you to query the effective year for that day.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * weekyear changed.
      *
      * @param weekyear  the weekyear to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withWeekyear(int weekyear) {
         return withLocalMillis(getChronology().weekyear().set(getLocalMillis(), weekyear));
     }
 
     /**
      * Returns a copy of this date with the month of year field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * month of year changed.
      *
      * @param monthOfYear  the month of year to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withMonthOfYear(int monthOfYear) {
         return withLocalMillis(getChronology().monthOfYear().set(getLocalMillis(), monthOfYear));
     }
 
     /**
      * Returns a copy of this date with the week of weekyear field updated.
      * <p>
      * This field is associated with the "weekyear" via {@link #withWeekyear(int)}.
      * In the standard ISO8601 week algorithm, the first week of the year
      * is that in which at least 4 days are in the year. As a result of this
      * definition, day 1 of the first week may be in the previous year.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * week of weekyear changed.
      *
      * @param weekOfWeekyear  the week of weekyear to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withWeekOfWeekyear(int weekOfWeekyear) {
         return withLocalMillis(getChronology().weekOfWeekyear().set(getLocalMillis(), weekOfWeekyear));
     }
 
     /**
      * Returns a copy of this date with the day of year field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * day of year changed.
      *
      * @param dayOfYear  the day of year to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withDayOfYear(int dayOfYear) {
         return withLocalMillis(getChronology().dayOfYear().set(getLocalMillis(), dayOfYear));
     }
 
     /**
      * Returns a copy of this date with the day of month field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * day of month changed.
      *
      * @param dayOfMonth  the day of month to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withDayOfMonth(int dayOfMonth) {
         return withLocalMillis(getChronology().dayOfMonth().set(getLocalMillis(), dayOfMonth));
     }
 
     /**
      * Returns a copy of this date with the day of week field updated.
      * <p>
      * LocalDate is immutable, so there are no set methods.
      * Instead, this method returns a new instance with the value of
      * day of week changed.
      *
      * @param dayOfWeek  the day of week to set
      * @return a copy of this object with the field set
      * @throws IllegalArgumentException if the value is invalid
      */
     public LocalDate withDayOfWeek(int dayOfWeek) {
         return withLocalMillis(getChronology().dayOfWeek().set(getLocalMillis(), dayOfWeek));
     }
 
     //-----------------------------------------------------------------------
     /**
      * Get the era property which provides access to advanced functionality.
      *
      * @return the era property
      */
     public Property era() {
         return new Property(this, getChronology().era());
     }
 
     /**
      * Get the century of era property which provides access to advanced functionality.
      *
      * @return the year of era property
      */
     public Property centuryOfEra() {
         return new Property(this, getChronology().centuryOfEra());
     }
 
     /**
      * Get the year of century property which provides access to advanced functionality.
      *
      * @return the year of era property
      */
     public Property yearOfCentury() {
         return new Property(this, getChronology().yearOfCentury());
     }
 
     /**
      * Get the year of era property which provides access to advanced functionality.
      *
      * @return the year of era property
      */
     public Property yearOfEra() {
         return new Property(this, getChronology().yearOfEra());
     }
 
     /**
      * Get the year property which provides access to advanced functionality.
      *
      * @return the year property
      */
     public Property year() {
         return new Property(this, getChronology().year());
     }
 
     /**
      * Get the weekyear property which provides access to advanced functionality.
      *
      * @return the weekyear property
      */
     public Property weekyear() {
         return new Property(this, getChronology().weekyear());
     }
 
     /**
      * Get the month of year property which provides access to advanced functionality.
      *
      * @return the month of year property
      */
     public Property monthOfYear() {
         return new Property(this, getChronology().monthOfYear());
     }
 
     /**
      * Get the week of a week based year property which provides access to advanced functionality.
      *
      * @return the week of a week based year property
      */
     public Property weekOfWeekyear() {
         return new Property(this, getChronology().weekOfWeekyear());
     }
 
     /**
      * Get the day of year property which provides access to advanced functionality.
      *
      * @return the day of year property
      */
     public Property dayOfYear() {
         return new Property(this, getChronology().dayOfYear());
     }
 
     /**
      * Get the day of month property which provides access to advanced functionality.
      *
      * @return the day of month property
      */
     public Property dayOfMonth() {
         return new Property(this, getChronology().dayOfMonth());
     }
 
     /**
      * Get the day of week property which provides access to advanced functionality.
      *
      * @return the day of week property
      */
     public Property dayOfWeek() {
         return new Property(this, getChronology().dayOfWeek());
     }
 
     //-----------------------------------------------------------------------
     /**
      * Output the date time in ISO8601 format (yyyy-MM-dd).
      *
      * @return ISO8601 time formatted string.
      */
     @ToString
     public String toString() {
         return ISODateTimeFormat.date().print(this);
     }
 
     /**
      * Output the date using the specified format pattern.
      *
      * @param pattern  the pattern specification, null means use <code>toString</code>
      * @see org.joda.time.format.DateTimeFormat
      */
     public String toString(String pattern) {
         if (pattern == null) {
             return toString();
         }
         return DateTimeFormat.forPattern(pattern).print(this);
     }
 
     /**
      * Output the date using the specified format pattern.
      *
      * @param pattern  the pattern specification, null means use <code>toString</code>
      * @param locale  Locale to use, null means default
      * @see org.joda.time.format.DateTimeFormat
      */
     public String toString(String pattern, Locale locale) throws IllegalArgumentException {
         if (pattern == null) {
             return toString();
         }
         return DateTimeFormat.forPattern(pattern).withLocale(locale).print(this);
     }
 
     //-----------------------------------------------------------------------
     /**
      * LocalDate.Property binds a LocalDate to a DateTimeField allowing
      * powerful datetime functionality to be easily accessed.
      * <p>
      * The simplest use of this class is as an alternative get method, here used to
      * get the year '1972' (as an int) and the month 'December' (as a String).
      * <pre>
      * LocalDate dt = new LocalDate(1972, 12, 3, 0, 0);
      * int year = dt.year().get();
      * String monthStr = dt.month().getAsText();
      * </pre>
      * <p>
      * Methods are also provided that allow date modification. These return
      * new instances of LocalDate - they do not modify the original. The example
      * below yields two independent immutable date objects 20 years apart.
      * <pre>
      * LocalDate dt = new LocalDate(1972, 12, 3);
      * LocalDate dt1920 = dt.year().setCopy(1920);
      * </pre>
      * <p>
      * LocalDate.Property itself is thread-safe and immutable, as well as the
      * LocalDate being operated on.
      *
      * @author Stephen Colebourne
      * @author Brian S O'Neill
      * @since 1.3
      */
     public static final class Property extends AbstractReadableInstantFieldProperty {
         
         /** Serialization version */
         private static final long serialVersionUID = -3193829732634L;
         
         /** The instant this property is working against */
         private transient LocalDate iInstant;
         /** The field this property is working against */
         private transient DateTimeField iField;
         
         /**
          * Constructor.
          * 
          * @param instant  the instant to set
          * @param field  the field to use
          */
         Property(LocalDate instant, DateTimeField field) {
             super();
             iInstant = instant;
             iField = field;
         }
         
         /**
          * Writes the property in a safe serialization format.
          */
         private void writeObject(ObjectOutputStream oos) throws IOException {
             oos.writeObject(iInstant);
             oos.writeObject(iField.getType());
         }
 
         /**
          * Reads the property from a safe serialization format.
          */
         private void readObject(ObjectInputStream oos) throws IOException, ClassNotFoundException {
             iInstant = (LocalDate) oos.readObject();
             DateTimeFieldType type = (DateTimeFieldType) oos.readObject();
             iField = type.getField(iInstant.getChronology());
         }
 
         //-----------------------------------------------------------------------
         /**
          * Gets the field being used.
          * 
          * @return the field
          */
         public DateTimeField getField() {
             return iField;
         }
         
         /**
          * Gets the milliseconds of the date that this property is linked to.
          * 
          * @return the milliseconds
          */
         protected long getMillis() {
             return iInstant.getLocalMillis();
         }
         
         /**
          * Gets the chronology of the datetime that this property is linked to.
          * 
          * @return the chronology
          * @since 1.4
          */
         protected Chronology getChronology() {
             return iInstant.getChronology();
         }
         
         /**
          * Gets the LocalDate object linked to this property.
          * 
          * @return the linked LocalDate
          */
         public LocalDate getLocalDate() {
             return iInstant;
         }
         
         //-----------------------------------------------------------------------
         /**
          * Adds to this field in a copy of this LocalDate.
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @param value  the value to add to the field in the copy
          * @return a copy of the LocalDate with the field value changed
          * @throws IllegalArgumentException if the value isn't valid
          */
         public LocalDate addToCopy(int value) {
             return iInstant.withLocalMillis(iField.add(iInstant.getLocalMillis(), value));
         }
         
         /**
          * Adds to this field, possibly wrapped, in a copy of this LocalDate.
          * A field wrapped operation only changes this field.
          * Thus 31st January addWrapField one day goes to the 1st January.
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @param value  the value to add to the field in the copy
          * @return a copy of the LocalDate with the field value changed
          * @throws IllegalArgumentException if the value isn't valid
          */
         public LocalDate addWrapFieldToCopy(int value) {
             return iInstant.withLocalMillis(iField.addWrapField(iInstant.getLocalMillis(), value));
         }
         
         //-----------------------------------------------------------------------
         /**
          * Sets this field in a copy of the LocalDate.
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @param value  the value to set the field in the copy to
          * @return a copy of the LocalDate with the field value changed
          * @throws IllegalArgumentException if the value isn't valid
          */
         public LocalDate setCopy(int value) {
             return iInstant.withLocalMillis(iField.set(iInstant.getLocalMillis(), value));
         }
         
         /**
          * Sets this field in a copy of the LocalDate to a parsed text value.
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @param text  the text value to set
          * @param locale  optional locale to use for selecting a text symbol
          * @return a copy of the LocalDate with the field value changed
          * @throws IllegalArgumentException if the text value isn't valid
          */
         public LocalDate setCopy(String text, Locale locale) {
             return iInstant.withLocalMillis(iField.set(iInstant.getLocalMillis(), text, locale));
         }
         
         /**
          * Sets this field in a copy of the LocalDate to a parsed text value.
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @param text  the text value to set
          * @return a copy of the LocalDate with the field value changed
          * @throws IllegalArgumentException if the text value isn't valid
          */
         public LocalDate setCopy(String text) {
             return setCopy(text, null);
         }
         
         //-----------------------------------------------------------------------
         /**
          * Returns a new LocalDate with this field set to the maximum value
          * for this field.
          * <p>
          * This operation is useful for obtaining a LocalDate on the last day
          * of the month, as month lengths vary.
          * <pre>
          * LocalDate lastDayOfMonth = dt.dayOfMonth().withMaximumValue();
          * </pre>
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @return a copy of the LocalDate with this field set to its maximum
          */
         public LocalDate withMaximumValue() {
             return setCopy(getMaximumValue());
         }
         
         /**
          * Returns a new LocalDate with this field set to the minimum value
          * for this field.
          * <p>
          * The LocalDate attached to this property is unchanged by this call.
          *
          * @return a copy of the LocalDate with this field set to its minimum
          */
         public LocalDate withMinimumValue() {
             return setCopy(getMinimumValue());
         }
         
         //-----------------------------------------------------------------------
         /**
          * Rounds to the lowest whole unit of this field on a copy of this
          * LocalDate.
          * <p>
          * For example, rounding floor on the hourOfDay field of a LocalDate
          * where the time is 10:30 would result in new LocalDate with the
          * time of 10:00.
          *
          * @return a copy of the LocalDate with the field value changed
          */
         public LocalDate roundFloorCopy() {
             return iInstant.withLocalMillis(iField.roundFloor(iInstant.getLocalMillis()));
         }
         
         /**
          * Rounds to the highest whole unit of this field on a copy of this
          * LocalDate.
          * <p>
          * For example, rounding floor on the hourOfDay field of a LocalDate
          * where the time is 10:30 would result in new LocalDate with the
          * time of 11:00.
          *
          * @return a copy of the LocalDate with the field value changed
          */
         public LocalDate roundCeilingCopy() {
             return iInstant.withLocalMillis(iField.roundCeiling(iInstant.getLocalMillis()));
         }
         
         /**
          * Rounds to the nearest whole unit of this field on a copy of this
          * LocalDate, favoring the floor if halfway.
          *
          * @return a copy of the LocalDate with the field value changed
          */
         public LocalDate roundHalfFloorCopy() {
             return iInstant.withLocalMillis(iField.roundHalfFloor(iInstant.getLocalMillis()));
         }
         
         /**
          * Rounds to the nearest whole unit of this field on a copy of this
          * LocalDate, favoring the ceiling if halfway.
          *
          * @return a copy of the LocalDate with the field value changed
          */
         public LocalDate roundHalfCeilingCopy() {
             return iInstant.withLocalMillis(iField.roundHalfCeiling(iInstant.getLocalMillis()));
         }
         
         /**
          * Rounds to the nearest whole unit of this field on a copy of this
          * LocalDate.  If halfway, the ceiling is favored over the floor
          * only if it makes this field's value even.
          *
          * @return a copy of the LocalDate with the field value changed
          */
         public LocalDate roundHalfEvenCopy() {
             return iInstant.withLocalMillis(iField.roundHalfEven(iInstant.getLocalMillis()));
         }
     }
 
 }