/*
 *  Copyright 2001-2007 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.Locale;

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.format.DateTimeFormat;
import org.joda.time.format.ISODateTimeFormat;

/**
 * LocalDateTime is an unmodifiable datetime class representing a
 * datetime without a time zone.
 * <p>
 * LocalDateTime implements the {@link ReadablePartial} interface.
 * To do this, certain methods focus on key fields Year, MonthOfYear,
 * DayOfYear and MillisOfDay.
 * However, <b>all</b> fields may in fact be queried.
 * <p>
 * Internally, LocalDateTime uses a single millisecond-based value to
 * represent the local datetime. This value is only used internally and
 * is not exposed to applications.
 * <p>
 * Calculations on LocalDateTime 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>getHourOfDay()</code>
 * <li><code>hourOfDay().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>
 * LocalDateTime 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 LocalDateTime
        extends BaseLocal
        implements ReadablePartial, Serializable {

    /** Serialization lock */
    private static final long serialVersionUID = -268716875315837168L;

    /** 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;
    /** The index of the millis field in the field array */
    private static final int MILLIS_OF_DAY = 3;

    /** The local millis from 1970-01-01T00:00:00 */
    private long iLocalMillis;
    /** The chronology to use in UTC */
    private Chronology iChronology;

    //-----------------------------------------------------------------------
    /**
     * Constructs a LocalDateTime from a <code>java.util.Calendar</code>
     * using exactly the same field values avoiding any time zone effects.
     * <p>
     * Each field is queried from the Calendar and assigned to the LocalDateTime.
     * This is useful if you have been using the Calendar as a local date,
     * ignoing the zone.
     * <p>
     * This factory method ignores the type of the calendar and always
     * creates a LocalDateTime 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
     * @return the created LocalDateTime
     * @throws IllegalArgumentException if the calendar is null
     * @throws IllegalArgumentException if the date is invalid for the ISO chronology
     */
    public static LocalDateTime fromCalendarFields(Calendar calendar) {
        if (calendar == null) {
            throw new IllegalArgumentException("The calendar must not be null");
        }
        return new LocalDateTime(
            calendar.get(Calendar.YEAR),
            calendar.get(Calendar.MONTH) + 1,
            calendar.get(Calendar.DAY_OF_MONTH),
            calendar.get(Calendar.HOUR_OF_DAY),
            calendar.get(Calendar.MINUTE),
            calendar.get(Calendar.SECOND),
            calendar.get(Calendar.MILLISECOND)
        );
    }

    /**
     * Constructs a LocalDateTime from a <code>java.util.Date</code>
     * using exactly the same field values avoiding any time zone effects.
     * <p>
     * Each field is queried from the Date and assigned to the LocalDateTime.
     * This is useful if you have been using the Date as a local date,
     * ignoing the zone.
     * <p>
     * This factory method always creates a LocalDateTime with ISO chronology.
     *
     * @param date  the Date to extract fields from
     * @return the created LocalDateTime
     * @throws IllegalArgumentException if the calendar is null
     * @throws IllegalArgumentException if the date is invalid for the ISO chronology
     */
    public static LocalDateTime fromDateFields(Date date) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        return new LocalDateTime(
            date.getYear() + 1900,
            date.getMonth() + 1,
            date.getDate(),
            date.getHours(),
            date.getMinutes(),
            date.getSeconds(),
            (int) (date.getTime() % 1000)
        );
    }

    //-----------------------------------------------------------------------
    /**
     * 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.
     */
    public LocalDateTime() {
        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
     */
    public LocalDateTime(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
     */
    public LocalDateTime(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 LocalDateTime(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 LocalDateTime(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 LocalDateTime(long instant, Chronology chronology) {
        chronology = DateTimeUtils.getChronology(chronology);
        
        long localMillis = chronology.getZone().getMillisKeepLocal(DateTimeZone.UTC, instant);
        iLocalMillis = localMillis;
        iChronology = chronology.withUTC();
    }

    //-----------------------------------------------------------------------
    /**
     * Constructs an instance from an Object that represents a datetime.
     * <p>
     * If the object contains no chronology, <code>ISOChronology</code> is used.
     * If the object contains no time zone, 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#localDateOptionalTimeParser()}.
     * 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 LocalDateTime(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#localDateOptionalTimeParser()}.
     * 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 LocalDateTime(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.localDateOptionalTimeParser());
        iLocalMillis = iChronology.getDateTimeMillis(values[0], values[1], values[2], values[3]);
    }

    /**
     * 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.
     * <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#localDateOptionalTimeParser()}.
     * 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 LocalDateTime(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.localDateOptionalTimeParser());
        iLocalMillis = iChronology.getDateTimeMillis(values[0], values[1], values[2], values[3]);
    }

    //-----------------------------------------------------------------------
    /**
     * 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
     * @param dayOfMonth  the day of the month
     * @param hourOfDay  the hour of the day
     * @param minuteOfHour  the minute of the hour
     */
    public LocalDateTime(
            int year,
            int monthOfYear,
            int dayOfMonth,
            int hourOfDay,
            int minuteOfHour) {
        this(year, monthOfYear, dayOfMonth, hourOfDay,
            minuteOfHour, 0, 0, ISOChronology.getInstanceUTC());
    }

    /**
     * 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
     * @param dayOfMonth  the day of the month
     * @param hourOfDay  the hour of the day
     * @param minuteOfHour  the minute of the hour
     * @param secondOfMinute  the second of the minute
     */
    public LocalDateTime(
            int year,
            int monthOfYear,
            int dayOfMonth,
            int hourOfDay,
            int minuteOfHour,
            int secondOfMinute) {
        this(year, monthOfYear, dayOfMonth, hourOfDay,
            minuteOfHour, secondOfMinute, 0, ISOChronology.getInstanceUTC());
    }

    /**
     * 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
     * @param dayOfMonth  the day of the month
     * @param hourOfDay  the hour of the day
     * @param minuteOfHour  the minute of the hour
     * @param secondOfMinute  the second of the minute
     * @param millisOfSecond  the millisecond of the second
     */
    public LocalDateTime(
            int year,
            int monthOfYear,
            int dayOfMonth,
            int hourOfDay,
            int minuteOfHour,
            int secondOfMinute,
            int millisOfSecond) {
        this(year, monthOfYear, dayOfMonth, hourOfDay,
            minuteOfHour, secondOfMinute, millisOfSecond, 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
     * @param monthOfYear  the month of the year
     * @param dayOfMonth  the day of the month
     * @param hourOfDay  the hour of the day
     * @param minuteOfHour  the minute of the hour
     * @param secondOfMinute  the second of the minute
     * @param millisOfSecond  the millisecond of the second
     * @param chronology  the chronology, null means ISOChronology in default zone
     */
    public LocalDateTime(
            int year,
            int monthOfYear,
            int dayOfMonth,
            int hourOfDay,
            int minuteOfHour,
            int secondOfMinute,
            int millisOfSecond,
            Chronology chronology) {
        super();
        chronology = DateTimeUtils.getChronology(chronology).withUTC();
        long instant = chronology.getDateTimeMillis(year, monthOfYear, dayOfMonth,
            hourOfDay, minuteOfHour, secondOfMinute, millisOfSecond);
        iChronology = chronology;
        iLocalMillis = instant;
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the number of fields in this partial, which is four.
     * The supported fields are Year, MonthOfDay, DayOfMonth and MillisOfDay.
     *
     * @return the field count, four
     */
    public int size() {
        return 4;
    }

    /**
     * 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();
            case MILLIS_OF_DAY:
                return chrono.millisOfDay();
            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, MonthOfDay, DayOfMonth and MillisOfDay.
     *
     * @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());
            case MILLIS_OF_DAY:
                return getChronology().millisOfDay().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>
     * DateTime dt = new DateTime();
     * int year = dt.get(DateTimeFieldType.year());
     * </pre>
     *
     * @param type  a field type, usually obtained from DateTimeFieldType, not null
     * @return the value of that field
     * @throws IllegalArgumentException if the field type is null
     */
    public int get(DateTimeFieldType type) {
        if (type == null) {
            throw new IllegalArgumentException("The DateTimeFieldType must not be null");
        }
        return type.getField(getChronology()).get(getLocalMillis());
    }

    /**
     * Checks if the field type specified is supported by this
     * local datetime 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;
        }
        return type.getField(getChronology()).isSupported();
    }

    /**
     * Checks if the duration type specified is supported by this
     * local datetime 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;
        }
        return type.getField(getChronology()).isSupported();
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the milliseconds of the datetime instant 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 datetime.
     *
     * @return the Chronology that the datetime 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 LocalDateTime) {
            LocalDateTime other = (LocalDateTime) partial;
            if (iChronology.equals(other.iChronology)) {
                return iLocalMillis == other.iLocalMillis;
            }
        }
        return super.equals(partial);
    }

    /**
     * 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.
     * <p>
     * NOTE: This implementation violates the Comparable contract.
     * This method will accept any instance of ReadablePartial as input.
     * However, it is possible that some implementations of ReadablePartial
     * exist that do not extend AbstractPartial, and thus will throw a
     * ClassCastException if compared in the opposite direction.
     * The cause of this problem is that ReadablePartial doesn't define
     * the compareTo() method, however we can't change that until v2.0.
     *
     * @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(Object partial) {
        // override to perform faster
        if (this == partial) {
            return 0;
        }
        if (partial instanceof LocalDateTime) {
            LocalDateTime other = (LocalDateTime) partial;
            if (iChronology.equals(other.iChronology)) {
                return (iLocalMillis < other.iLocalMillis ? -1 :
                            (iLocalMillis == other.iLocalMillis ? 0 : 1));

            }
        }
        return super.compareTo(partial);
    }

    //-----------------------------------------------------------------------
    /**
     * Converts this object to a DateTime using the default zone.
     * <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.
     * 
     * @return <code>this</code>
     */
    public DateTime toDateTime() {
        return toDateTime((DateTimeZone) null);
    }

    /**
     * Converts this object to a DateTime using the specified zone.
     * <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.
     * 
     * @param zone time zone to apply, or default if null
     * @return a DateTime using the same millis
     */
    public DateTime toDateTime(DateTimeZone zone) {
        zone = DateTimeUtils.getZone(zone);
        Chronology chrono = iChronology.withZone(zone);
        return new DateTime(
                getYear(), getMonthOfYear(), getDayOfMonth(),
                getHourOfDay(), getMinuteOfHour(),
                getSecondOfMinute(), getMillisOfSecond(), chrono);
    }

    //-----------------------------------------------------------------------
    /**
     * Converts this object to a LocalDate with the same date and chronology.
     *
     * @return a LocalDate with the same date and chronology
     */
    public LocalDate toLocalDate() {
        return new LocalDate(getLocalMillis(), getChronology());
    }

    /**
     * Converts this object to a LocalTime with the same time and chronology.
     *
     * @return a LocalTime with the same time and chronology
     */
    public LocalTime toLocalTime() {
        return new LocalTime(getLocalMillis(), getChronology());
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime 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 datetime with different millis
     */
    LocalDateTime withLocalMillis(long newMillis) {
        return (newMillis == getLocalMillis() ? this : new LocalDateTime(newMillis, getChronology()));
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the specified date,
     * retaining the time fields.
     * <p>
     * If the date is already the date passed in, then <code>this</code> is returned.
     * <p>
     * To set a single field use the properties, for example:
     * <pre>
     * DateTime set = dt.monthOfYear().setCopy(6);
     * </pre>
     *
     * @param year  the new year value
     * @param monthOfYear  the new monthOfYear value
     * @param dayOfMonth  the new dayOfMonth value
     * @return a copy of this datetime with a different date
     * @throws IllegalArgumentException if any value if invalid
     */
    public LocalDateTime withDate(int year, int monthOfYear, int dayOfMonth) {
        Chronology chrono = getChronology();
        long instant = getLocalMillis();
        instant = chrono.year().set(instant, year);
        instant = chrono.monthOfYear().set(instant, monthOfYear);
        instant = chrono.dayOfMonth().set(instant, dayOfMonth);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime with the specified time,
     * retaining the date fields.
     * <p>
     * If the time is already the time passed in, then <code>this</code> is returned.
     * <p>
     * To set a single field use the properties, for example:
     * <pre>
     * LocalDateTime set = dt.hourOfDay().setCopy(6);
     * </pre>
     *
     * @param hourOfDay  the hour of the day
     * @param minuteOfHour  the minute of the hour
     * @param secondOfMinute  the second of the minute
     * @param millisOfSecond  the millisecond of the second
     * @return a copy of this datetime with a different time
     * @throws IllegalArgumentException if any value if invalid
     */
    public LocalDateTime withTime(int hourOfDay, int minuteOfHour, int secondOfMinute, int millisOfSecond) {
        Chronology chrono = getChronology();
        long instant = getLocalMillis();
        instant = chrono.hourOfDay().set(instant, hourOfDay);
        instant = chrono.minuteOfHour().set(instant, minuteOfHour);
        instant = chrono.secondOfMinute().set(instant, secondOfMinute);
        instant = chrono.millisOfSecond().set(instant, millisOfSecond);
        return withLocalMillis(instant);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the partial set of fields
     * replacing those from this instance.
     * <p>
     * For example, if the partial is a <code>TimeOfDay</code> then the time fields
     * would be changed in the returned instance.
     * If the partial is null, then <code>this</code> is returned.
     *
     * @param partial  the partial set of fields to apply to this datetime, null ignored
     * @return a copy of this datetime with a different set of fields
     * @throws IllegalArgumentException if any value is invalid
     */
    public LocalDateTime withFields(ReadablePartial partial) {
        if (partial == null) {
            return this;
        }
        return withLocalMillis(getChronology().set(partial, getLocalMillis()));
    }

    /**
     * Returns a copy of this datetime with the specified field set to a new value.
     * <p>
     * For example, if the field type is <code>hourOfDay</code> then the hour of day
     * field would be changed in the returned instance.
     * If the field type is null, then <code>this</code> is returned.
     * <p>
     * These three lines are equivalent:
     * <pre>
     * LocalDateTime updated = dt.withField(DateTimeFieldType.dayOfMonth(), 6);
     * LocalDateTime updated = dt.dayOfMonth().setCopy(6);
     * LocalDateTime updated = dt.property(DateTimeFieldType.dayOfMonth()).setCopy(6);
     * </pre>
     *
     * @param fieldType  the field type to set, not null
     * @param value  the value to set
     * @return a copy of this datetime with the field set
     * @throws IllegalArgumentException if the value is null or invalid
     */
    public LocalDateTime withField(DateTimeFieldType fieldType, int value) {
        if (fieldType == null) {
            throw new IllegalArgumentException("Field must not be null");
        }
        long instant = fieldType.getField(getChronology()).set(getLocalMillis(), value);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime 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>
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.years(), 6);
     * LocalDateTime added = dt.plusYears(6);
     * LocalDateTime 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 datetime with the field updated
     * @throws IllegalArgumentException if the value is null or invalid
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime withFieldAdded(DurationFieldType fieldType, int amount) {
        if (fieldType == null) {
            throw new IllegalArgumentException("Field must not be null");
        }
        if (amount == 0) {
            return this;
        }
        long instant = fieldType.getField(getChronology()).add(getLocalMillis(), amount);
        return withLocalMillis(instant);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the specified duration added.
     * <p>
     * If the addition is zero, then <code>this</code> is returned.
     *
     * @param durationToAdd  the duration 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 datetime with the duration added
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime withDurationAdded(ReadableDuration durationToAdd, int scalar) {
        if (durationToAdd == null || scalar == 0) {
            return this;
        }
        long instant = getChronology().add(getLocalMillis(), durationToAdd.getMillis(), scalar);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime 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)}.
     *
     * @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 datetime with the period added
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime withPeriodAdded(ReadablePeriod period, int scalar) {
        if (period == null || scalar == 0) {
            return this;
        }
        long instant = getChronology().add(period, getLocalMillis(), scalar);
        return withLocalMillis(instant);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the specified duration added.
     * <p>
     * If the amount is zero or null, then <code>this</code> is returned.
     *
     * @param duration  the duration to add to this one, null means zero
     * @return a copy of this datetime with the duration added
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime plus(ReadableDuration duration) {
        return withDurationAdded(duration, 1);
    }

    /**
     * Returns a copy of this datetime 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)}.
     *
     * @param period  the period to add to this one, null means zero
     * @return a copy of this datetime with the period added
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime plus(ReadablePeriod period) {
        return withPeriodAdded(period, 1);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime plus the specified number of years.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusYears(6);
     * LocalDateTime added = dt.plus(Period.years(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.years(), 6);
     * </pre>
     *
     * @param years  the amount of years to add, may be negative
     * @return the new LocalDateTime plus the increased years
     */
    public LocalDateTime plusYears(int years) {
        if (years == 0) {
            return this;
        }
        long instant = getChronology().years().add(getLocalMillis(), years);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime plus the specified number of months.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusMonths(6);
     * LocalDateTime added = dt.plus(Period.months(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.months(), 6);
     * </pre>
     *
     * @param months  the amount of months to add, may be negative
     * @return the new LocalDateTime plus the increased months
     */
    public LocalDateTime plusMonths(int months) {
        if (months == 0) {
            return this;
        }
        long instant = getChronology().months().add(getLocalMillis(), months);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime plus the specified number of weeks.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusWeeks(6);
     * LocalDateTime added = dt.plus(Period.weeks(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.weeks(), 6);
     * </pre>
     *
     * @param weeks  the amount of weeks to add, may be negative
     * @return the new LocalDateTime plus the increased weeks
     */
    public LocalDateTime plusWeeks(int weeks) {
        if (weeks == 0) {
            return this;
        }
        long instant = getChronology().weeks().add(getLocalMillis(), weeks);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime plus the specified number of days.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusDays(6);
     * LocalDateTime added = dt.plus(Period.days(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.days(), 6);
     * </pre>
     *
     * @param days  the amount of days to add, may be negative
     * @return the new LocalDateTime plus the increased days
     */
    public LocalDateTime plusDays(int days) {
        if (days == 0) {
            return this;
        }
        long instant = getChronology().days().add(getLocalMillis(), days);
        return withLocalMillis(instant);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime plus the specified number of hours.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusHours(6);
     * LocalDateTime added = dt.plus(Period.hours(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.hours(), 6);
     * </pre>
     *
     * @param hours  the amount of hours to add, may be negative
     * @return the new LocalDateTime plus the increased hours
     */
    public LocalDateTime plusHours(int hours) {
        if (hours == 0) {
            return this;
        }
        long instant = getChronology().hours().add(getLocalMillis(), hours);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime plus the specified number of minutes.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusMinutes(6);
     * LocalDateTime added = dt.plus(Period.minutes(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.minutes(), 6);
     * </pre>
     *
     * @param minutes  the amount of minutes to add, may be negative
     * @return the new LocalDateTime plus the increased minutes
     */
    public LocalDateTime plusMinutes(int minutes) {
        if (minutes == 0) {
            return this;
        }
        long instant = getChronology().minutes().add(getLocalMillis(), minutes);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime plus the specified number of seconds.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusSeconds(6);
     * LocalDateTime added = dt.plus(Period.seconds(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.seconds(), 6);
     * </pre>
     *
     * @param seconds  the amount of seconds to add, may be negative
     * @return the new LocalDateTime plus the increased seconds
     */
    public LocalDateTime plusSeconds(int seconds) {
        if (seconds == 0) {
            return this;
        }
        long instant = getChronology().seconds().add(getLocalMillis(), seconds);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime plus the specified number of millis.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime added = dt.plusMillis(6);
     * LocalDateTime added = dt.plus(Period.millis(6));
     * LocalDateTime added = dt.withFieldAdded(DurationFieldType.millis(), 6);
     * </pre>
     *
     * @param millis  the amount of millis to add, may be negative
     * @return the new LocalDateTime plus the increased millis
     */
    public LocalDateTime plusMillis(int millis) {
        if (millis == 0) {
            return this;
        }
        long instant = getChronology().millis().add(getLocalMillis(), millis);
        return withLocalMillis(instant);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the specified duration taken away.
     * <p>
     * If the amount is zero or null, then <code>this</code> is returned.
     *
     * @param duration  the duration to reduce this instant by
     * @return a copy of this datetime with the duration taken away
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime minus(ReadableDuration duration) {
        return withDurationAdded(duration, -1);
    }

    /**
     * Returns a copy of this datetime 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)}.
     *
     * @param period  the period to reduce this instant by
     * @return a copy of this datetime with the period taken away
     * @throws ArithmeticException if the result exceeds the internal capacity
     */
    public LocalDateTime minus(ReadablePeriod period) {
        return withPeriodAdded(period, -1);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime minus the specified number of years.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusYears(6);
     * LocalDateTime subtracted = dt.minus(Period.years(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.years(), -6);
     * </pre>
     *
     * @param years  the amount of years to subtract, may be negative
     * @return the new LocalDateTime minus the increased years
     */
    public LocalDateTime minusYears(int years) {
        if (years == 0) {
            return this;
        }
        long instant = getChronology().years().subtract(getLocalMillis(), years);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime minus the specified number of months.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusMonths(6);
     * LocalDateTime subtracted = dt.minus(Period.months(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.months(), -6);
     * </pre>
     *
     * @param months  the amount of months to subtract, may be negative
     * @return the new LocalDateTime minus the increased months
     */
    public LocalDateTime minusMonths(int months) {
        if (months == 0) {
            return this;
        }
        long instant = getChronology().months().subtract(getLocalMillis(), months);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime minus the specified number of weeks.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusWeeks(6);
     * LocalDateTime subtracted = dt.minus(Period.weeks(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.weeks(), -6);
     * </pre>
     *
     * @param weeks  the amount of weeks to subtract, may be negative
     * @return the new LocalDateTime minus the increased weeks
     */
    public LocalDateTime minusWeeks(int weeks) {
        if (weeks == 0) {
            return this;
        }
        long instant = getChronology().weeks().subtract(getLocalMillis(), weeks);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime minus the specified number of days.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusDays(6);
     * LocalDateTime subtracted = dt.minus(Period.days(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.days(), -6);
     * </pre>
     *
     * @param days  the amount of days to subtract, may be negative
     * @return the new LocalDateTime minus the increased days
     */
    public LocalDateTime minusDays(int days) {
        if (days == 0) {
            return this;
        }
        long instant = getChronology().days().subtract(getLocalMillis(), days);
        return withLocalMillis(instant);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime minus the specified number of hours.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusHours(6);
     * LocalDateTime subtracted = dt.minus(Period.hours(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.hours(), -6);
     * </pre>
     *
     * @param hours  the amount of hours to subtract, may be negative
     * @return the new LocalDateTime minus the increased hours
     */
    public LocalDateTime minusHours(int hours) {
        if (hours == 0) {
            return this;
        }
        long instant = getChronology().hours().subtract(getLocalMillis(), hours);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime minus the specified number of minutes.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusMinutes(6);
     * LocalDateTime subtracted = dt.minus(Period.minutes(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.minutes(), -6);
     * </pre>
     *
     * @param minutes  the amount of minutes to subtract, may be negative
     * @return the new LocalDateTime minus the increased minutes
     */
    public LocalDateTime minusMinutes(int minutes) {
        if (minutes == 0) {
            return this;
        }
        long instant = getChronology().minutes().subtract(getLocalMillis(), minutes);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime minus the specified number of seconds.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusSeconds(6);
     * LocalDateTime subtracted = dt.minus(Period.seconds(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.seconds(), -6);
     * </pre>
     *
     * @param seconds  the amount of seconds to subtract, may be negative
     * @return the new LocalDateTime minus the increased seconds
     */
    public LocalDateTime minusSeconds(int seconds) {
        if (seconds == 0) {
            return this;
        }
        long instant = getChronology().seconds().subtract(getLocalMillis(), seconds);
        return withLocalMillis(instant);
    }

    /**
     * Returns a copy of this datetime minus the specified number of millis.
     * <p>
     * This LocalDateTime instance is immutable and unaffected by this method call.
     * <p>
     * The following three lines are identical in effect:
     * <pre>
     * LocalDateTime subtracted = dt.minusMillis(6);
     * LocalDateTime subtracted = dt.minus(Period.millis(6));
     * LocalDateTime subtracted = dt.withFieldAdded(DurationFieldType.millis(), -6);
     * </pre>
     *
     * @param millis  the amount of millis to subtract, may be negative
     * @return the new LocalDateTime minus the increased millis
     */
    public LocalDateTime minusMillis(int millis) {
        if (millis == 0) {
            return this;
        }
        long instant = getChronology().millis().subtract(getLocalMillis(), millis);
        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.
     *
     * @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());
    }

    //-----------------------------------------------------------------------
    /**
     * Get the hour of day field value.
     *
     * @return the hour of day
     */
    public int getHourOfDay() {
        return getChronology().hourOfDay().get(getLocalMillis());
    }

    /**
     * Get the minute of hour field value.
     *
     * @return the minute of hour
     */
    public int getMinuteOfHour() {
        return getChronology().minuteOfHour().get(getLocalMillis());
    }

    /**
     * Get the second of minute field value.
     *
     * @return the second of minute
     */
    public int getSecondOfMinute() {
        return getChronology().secondOfMinute().get(getLocalMillis());
    }

    /**
     * Get the millis of second field value.
     *
     * @return the millis of second
     */
    public int getMillisOfSecond() {
        return getChronology().millisOfSecond().get(getLocalMillis());
    }

    /**
     * Get the millis of day field value.
     *
     * @return the millis of day
     */
    public int getMillisOfDay() {
        return getChronology().millisOfDay().get(getLocalMillis());
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the era field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withEra(int era) {
        return withLocalMillis(getChronology().era().set(getLocalMillis(), era));
    }

    /**
     * Returns a copy of this datetime with the century of era field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withCenturyOfEra(int centuryOfEra) {
        return withLocalMillis(getChronology().centuryOfEra().set(getLocalMillis(), centuryOfEra));
    }

    /**
     * Returns a copy of this datetime with the year of era field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withYearOfEra(int yearOfEra) {
        return withLocalMillis(getChronology().yearOfEra().set(getLocalMillis(), yearOfEra));
    }

    /**
     * Returns a copy of this datetime with the year of century field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withYearOfCentury(int yearOfCentury) {
        return withLocalMillis(getChronology().yearOfCentury().set(getLocalMillis(), yearOfCentury));
    }

    /**
     * Returns a copy of this datetime with the year field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withYear(int year) {
        return withLocalMillis(getChronology().year().set(getLocalMillis(), year));
    }

    /**
     * Returns a copy of this datetime with the weekyear field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withWeekyear(int weekyear) {
        return withLocalMillis(getChronology().weekyear().set(getLocalMillis(), weekyear));
    }

    /**
     * Returns a copy of this datetime with the month of year field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withMonthOfYear(int monthOfYear) {
        return withLocalMillis(getChronology().monthOfYear().set(getLocalMillis(), monthOfYear));
    }

    /**
     * Returns a copy of this datetime with the week of weekyear field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withWeekOfWeekyear(int weekOfWeekyear) {
        return withLocalMillis(getChronology().weekOfWeekyear().set(getLocalMillis(), weekOfWeekyear));
    }

    /**
     * Returns a copy of this datetime with the day of year field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withDayOfYear(int dayOfYear) {
        return withLocalMillis(getChronology().dayOfYear().set(getLocalMillis(), dayOfYear));
    }

    /**
     * Returns a copy of this datetime with the day of month field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withDayOfMonth(int dayOfMonth) {
        return withLocalMillis(getChronology().dayOfMonth().set(getLocalMillis(), dayOfMonth));
    }

    /**
     * Returns a copy of this datetime with the day of week field updated.
     * <p>
     * LocalDateTime 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 LocalDateTime withDayOfWeek(int dayOfWeek) {
        return withLocalMillis(getChronology().dayOfWeek().set(getLocalMillis(), dayOfWeek));
    }

    //-----------------------------------------------------------------------
    /**
     * Returns a copy of this datetime with the hour of day field updated.
     * <p>
     * LocalDateTime is immutable, so there are no set methods.
     * Instead, this method returns a new instance with the value of
     * hour of day changed.
     *
     * @param hour  the hour of day to set
     * @return a copy of this object with the field set
     * @throws IllegalArgumentException if the value is invalid
     */
    public LocalDateTime withHourOfDay(int hour) {
        return withLocalMillis(getChronology().hourOfDay().set(getLocalMillis(), hour));
    }

    /**
     * Returns a copy of this datetime with the minute of hour field updated.
     * <p>
     * LocalDateTime is immutable, so there are no set methods.
     * Instead, this method returns a new instance with the value of
     * minute of hour changed.
     *
     * @param minute  the minute of hour to set
     * @return a copy of this object with the field set
     * @throws IllegalArgumentException if the value is invalid
     */
    public LocalDateTime withMinuteOfHour(int minute) {
        return withLocalMillis(getChronology().minuteOfHour().set(getLocalMillis(), minute));
    }

    /**
     * Returns a copy of this datetime with the second of minute field updated.
     * <p>
     * LocalDateTime is immutable, so there are no set methods.
     * Instead, this method returns a new instance with the value of
     * second of minute changed.
     *
     * @param second  the second of minute to set
     * @return a copy of this object with the field set
     * @throws IllegalArgumentException if the value is invalid
     */
    public LocalDateTime withSecondOfMinute(int second) {
        return withLocalMillis(getChronology().secondOfMinute().set(getLocalMillis(), second));
    }

    /**
     * Returns a copy of this datetime with the millis of second field updated.
     * <p>
     * LocalDateTime is immutable, so there are no set methods.
     * Instead, this method returns a new instance with the value of
     * millis of second changed.
     *
     * @param millis  the millis of second to set
     * @return a copy of this object with the field set
     * @throws IllegalArgumentException if the value is invalid
     */
    public LocalDateTime withMillisOfSecond(int millis) {
        return withLocalMillis(getChronology().millisOfSecond().set(getLocalMillis(), millis));
    }

    /**
     * Returns a copy of this datetime with the millis of day field updated.
     * <p>
     * LocalDateTime is immutable, so there are no set methods.
     * Instead, this method returns a new instance with the value of
     * millis of day changed.
     *
     * @param millis  the millis of day to set
     * @return a copy of this object with the field set
     * @throws IllegalArgumentException if the value is invalid
     */
    public LocalDateTime withMillisOfDay(int millis) {
        return withLocalMillis(getChronology().millisOfDay().set(getLocalMillis(), millis));
    }

    //-----------------------------------------------------------------------
    /**
     * 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());
    }

    //-----------------------------------------------------------------------
    /**
     * Get the hour of day field property which provides access to advanced functionality.
     * 
     * @return the hour of day property
     */
    public Property hourOfDay() {
        return new Property(this, getChronology().hourOfDay());
    }

    /**
     * Get the minute of hour field property which provides access to advanced functionality.
     * 
     * @return the minute of hour property
     */
    public Property minuteOfHour() {
        return new Property(this, getChronology().minuteOfHour());
    }

    /**
     * Get the second of minute field property which provides access to advanced functionality.
     * 
     * @return the second of minute property
     */
    public Property secondOfMinute() {
        return new Property(this, getChronology().secondOfMinute());
    }

    /**
     * Get the millis of second property which provides access to advanced functionality.
     * 
     * @return the millis of second property
     */
    public Property millisOfSecond() {
        return new Property(this, getChronology().millisOfSecond());
    }

    /**
     * Get the millis of day property which provides access to advanced functionality.
     * 
     * @return the millis of day property
     */
    public Property millisOfDay() {
        return new Property(this, getChronology().millisOfDay());
    }

    //-----------------------------------------------------------------------
    /**
     * Output the date time in ISO8601 format (yyyy-MM-ddTHH:mm:ss.SSS).
     * 
     * @return ISO8601 time formatted string.
     */
    public String toString() {
        return ISODateTimeFormat.dateTime().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);
    }

    //-----------------------------------------------------------------------
    /**
     * LocalDateTime.Property binds a LocalDateTime 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>
     * LocalDateTime dt = new LocalDateTime(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 LocalDateTime - they do not modify the original.
     * The example below yields two independent immutable date objects
     * 20 years apart.
     * <pre>
     * LocalDateTime dt = new LocalDateTime(1972, 12, 3, 0, 0);
     * LocalDateTime dt1920 = dt.year().setCopy(1920);
     * </pre>
     * <p>
     * LocalDateTime.Property itself is thread-safe and immutable, as well as the
     * LocalDateTime 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 = -358138762846288L;
        
        /** The instant this property is working against */
        private transient LocalDateTime 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(LocalDateTime 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 = (LocalDateTime) 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 datetime 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 LocalDateTime object linked to this property.
         * 
         * @return the linked LocalDateTime
         */
        public LocalDateTime getLocalDateTime() {
            return iInstant;
        }
        
        //-----------------------------------------------------------------------
        /**
         * Adds to this field in a copy of this LocalDateTime.
         * <p>
         * The LocalDateTime 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 LocalDateTime with the field value changed
         * @throws IllegalArgumentException if the value isn't valid
         */
        public LocalDateTime addToCopy(int value) {
            return iInstant.withLocalMillis(iField.add(iInstant.getLocalMillis(), value));
        }
        
        /**
         * Adds to this field in a copy of this LocalDateTime.
         * <p>
         * The LocalDateTime 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 LocalDateTime with the field value changed
         * @throws IllegalArgumentException if the value isn't valid
         */
        public LocalDateTime addToCopy(long value) {
            return iInstant.withLocalMillis(iField.add(iInstant.getLocalMillis(), value));
        }
        
        /**
         * Adds to this field, possibly wrapped, in a copy of this LocalDateTime.
         * A field wrapped operation only changes this field.
         * Thus 31st January addWrapField one day goes to the 1st January.
         * <p>
         * The LocalDateTime 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 LocalDateTime with the field value changed
         * @throws IllegalArgumentException if the value isn't valid
         */
        public LocalDateTime addWrapFieldToCopy(int value) {
            return iInstant.withLocalMillis(iField.addWrapField(iInstant.getLocalMillis(), value));
        }
        
        //-----------------------------------------------------------------------
        /**
         * Sets this field in a copy of the LocalDateTime.
         * <p>
         * The LocalDateTime 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 LocalDateTime with the field value changed
         * @throws IllegalArgumentException if the value isn't valid
         */
        public LocalDateTime setCopy(int value) {
            return iInstant.withLocalMillis(iField.set(iInstant.getLocalMillis(), value));
        }
        
        /**
         * Sets this field in a copy of the LocalDateTime to a parsed text value.
         * <p>
         * The LocalDateTime 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 LocalDateTime with the field value changed
         * @throws IllegalArgumentException if the text value isn't valid
         */
        public LocalDateTime setCopy(String text, Locale locale) {
            return iInstant.withLocalMillis(iField.set(iInstant.getLocalMillis(), text, locale));
        }
        
        /**
         * Sets this field in a copy of the LocalDateTime to a parsed text value.
         * <p>
         * The LocalDateTime attached to this property is unchanged by this call.
         *
         * @param text  the text value to set
         * @return a copy of the LocalDateTime with the field value changed
         * @throws IllegalArgumentException if the text value isn't valid
         */
        public LocalDateTime setCopy(String text) {
            return setCopy(text, null);
        }
        
        //-----------------------------------------------------------------------
        /**
         * Returns a new LocalDateTime with this field set to the maximum value
         * for this field.
         * <p>
         * This operation is useful for obtaining a LocalDateTime on the last day
         * of the month, as month lengths vary.
         * <pre>
         * LocalDateTime lastDayOfMonth = dt.dayOfMonth().withMaximumValue();
         * </pre>
         * <p>
         * The LocalDateTime attached to this property is unchanged by this call.
         *
         * @return a copy of the LocalDateTime with this field set to its maximum
         */
        public LocalDateTime withMaximumValue() {
            return setCopy(getMaximumValue());
        }
        
        /**
         * Returns a new LocalDateTime with this field set to the minimum value
         * for this field.
         * <p>
         * The LocalDateTime attached to this property is unchanged by this call.
         *
         * @return a copy of the LocalDateTime with this field set to its minimum
         */
        public LocalDateTime withMinimumValue() {
            return setCopy(getMinimumValue());
        }
        
        //-----------------------------------------------------------------------
        /**
         * Rounds to the lowest whole unit of this field on a copy of this
         * LocalDateTime.
         * <p>
         * For example, rounding floor on the hourOfDay field of a LocalDateTime
         * where the time is 10:30 would result in new LocalDateTime with the
         * time of 10:00.
         *
         * @return a copy of the LocalDateTime with the field value changed
         */
        public LocalDateTime roundFloorCopy() {
            return iInstant.withLocalMillis(iField.roundFloor(iInstant.getLocalMillis()));
        }
        
        /**
         * Rounds to the highest whole unit of this field on a copy of this
         * LocalDateTime.
         * <p>
         * For example, rounding floor on the hourOfDay field of a LocalDateTime
         * where the time is 10:30 would result in new LocalDateTime with the
         * time of 11:00.
         *
         * @return a copy of the LocalDateTime with the field value changed
         */
        public LocalDateTime roundCeilingCopy() {
            return iInstant.withLocalMillis(iField.roundCeiling(iInstant.getLocalMillis()));
        }
        
        /**
         * Rounds to the nearest whole unit of this field on a copy of this
         * LocalDateTime, favoring the floor if halfway.
         *
         * @return a copy of the LocalDateTime with the field value changed
         */
        public LocalDateTime roundHalfFloorCopy() {
            return iInstant.withLocalMillis(iField.roundHalfFloor(iInstant.getLocalMillis()));
        }
        
        /**
         * Rounds to the nearest whole unit of this field on a copy of this
         * LocalDateTime, favoring the ceiling if halfway.
         *
         * @return a copy of the LocalDateTime with the field value changed
         */
        public LocalDateTime roundHalfCeilingCopy() {
            return iInstant.withLocalMillis(iField.roundHalfCeiling(iInstant.getLocalMillis()));
        }
        
        /**
         * Rounds to the nearest whole unit of this field on a copy of this
         * LocalDateTime.  If halfway, the ceiling is favored over the floor
         * only if it makes this field's value even.
         *
         * @return a copy of the LocalDateTime with the field value changed
         */
        public LocalDateTime roundHalfEvenCopy() {
            return iInstant.withLocalMillis(iField.roundHalfEven(iInstant.getLocalMillis()));
        }
    }

}
