Java example source code file (Period.java)
The Period.java Java example source code/*
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/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Copyright (c) 2008-2012, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
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package java.time;
import static java.time.temporal.ChronoUnit.DAYS;
import static java.time.temporal.ChronoUnit.MONTHS;
import static java.time.temporal.ChronoUnit.YEARS;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.chrono.ChronoLocalDate;
import java.time.chrono.ChronoPeriod;
import java.time.chrono.Chronology;
import java.time.chrono.IsoChronology;
import java.time.format.DateTimeParseException;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAmount;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalUnit;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A date-based amount of time in the ISO-8601 calendar system,
* such as '2 years, 3 months and 4 days'.
* <p>
* This class models a quantity or amount of time in terms of years, months and days.
* See {@link Duration} for the time-based equivalent to this class.
* <p>
* Durations and periods differ in their treatment of daylight savings time
* when added to {@link ZonedDateTime}. A {@code Duration} will add an exact
* number of seconds, thus a duration of one day is always exactly 24 hours.
* By contrast, a {@code Period} will add a conceptual day, trying to maintain
* the local time.
* <p>
* For example, consider adding a period of one day and a duration of one day to
* 18:00 on the evening before a daylight savings gap. The {@code Period} will add
* the conceptual day and result in a {@code ZonedDateTime} at 18:00 the following day.
* By contrast, the {@code Duration} will add exactly 24 hours, resulting in a
* {@code ZonedDateTime} at 19:00 the following day (assuming a one hour DST gap).
* <p>
* The supported units of a period are {@link ChronoUnit#YEARS YEARS},
* {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}.
* All three fields are always present, but may be set to zero.
* <p>
* The ISO-8601 calendar system is the modern civil calendar system used today
* in most of the world. It is equivalent to the proleptic Gregorian calendar
* system, in which today's rules for leap years are applied for all time.
* <p>
* The period is modeled as a directed amount of time, meaning that individual parts of the
* period may be negative.
*
* <p>
* This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based
* class; use of identity-sensitive operations (including reference equality
* ({@code ==}), identity hash code, or synchronization) on instances of
* {@code Period} may have unpredictable results and should be avoided.
* The {@code equals} method should be used for comparisons.
*
* @implSpec
* This class is immutable and thread-safe.
*
* @since 1.8
*/
public final class Period
implements ChronoPeriod, Serializable {
/**
* A constant for a period of zero.
*/
public static final Period ZERO = new Period(0, 0, 0);
/**
* Serialization version.
*/
private static final long serialVersionUID = -3587258372562876L;
/**
* The pattern for parsing.
*/
private static final Pattern PATTERN =
Pattern.compile("([-+]?)P(?:([-+]?[0-9]+)Y)?(?:([-+]?[0-9]+)M)?(?:([-+]?[0-9]+)W)?(?:([-+]?[0-9]+)D)?", Pattern.CASE_INSENSITIVE);
/**
* The set of supported units.
*/
private static final List<TemporalUnit> SUPPORTED_UNITS =
Collections.unmodifiableList(Arrays.<TemporalUnit>asList(YEARS, MONTHS, DAYS));
/**
* The number of years.
*/
private final int years;
/**
* The number of months.
*/
private final int months;
/**
* The number of days.
*/
private final int days;
//-----------------------------------------------------------------------
/**
* Obtains a {@code Period} representing a number of years.
* <p>
* The resulting period will have the specified years.
* The months and days units will be zero.
*
* @param years the number of years, positive or negative
* @return the period of years, not null
*/
public static Period ofYears(int years) {
return create(years, 0, 0);
}
/**
* Obtains a {@code Period} representing a number of months.
* <p>
* The resulting period will have the specified months.
* The years and days units will be zero.
*
* @param months the number of months, positive or negative
* @return the period of months, not null
*/
public static Period ofMonths(int months) {
return create(0, months, 0);
}
/**
* Obtains a {@code Period} representing a number of weeks.
* <p>
* The resulting period will be day-based, with the amount of days
* equal to the number of weeks multiplied by 7.
* The years and months units will be zero.
*
* @param weeks the number of weeks, positive or negative
* @return the period, with the input weeks converted to days, not null
*/
public static Period ofWeeks(int weeks) {
return create(0, 0, Math.multiplyExact(weeks, 7));
}
/**
* Obtains a {@code Period} representing a number of days.
* <p>
* The resulting period will have the specified days.
* The years and months units will be zero.
*
* @param days the number of days, positive or negative
* @return the period of days, not null
*/
public static Period ofDays(int days) {
return create(0, 0, days);
}
//-----------------------------------------------------------------------
/**
* Obtains a {@code Period} representing a number of years, months and days.
* <p>
* This creates an instance based on years, months and days.
*
* @param years the amount of years, may be negative
* @param months the amount of months, may be negative
* @param days the amount of days, may be negative
* @return the period of years, months and days, not null
*/
public static Period of(int years, int months, int days) {
return create(years, months, days);
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code Period} from a temporal amount.
* <p>
* This obtains a period based on the specified amount.
* A {@code TemporalAmount} represents an amount of time, which may be
* date-based or time-based, which this factory extracts to a {@code Period}.
* <p>
* The conversion loops around the set of units from the amount and uses
* the {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS}
* and {@link ChronoUnit#DAYS DAYS} units to create a period.
* If any other units are found then an exception is thrown.
* <p>
* If the amount is a {@code ChronoPeriod} then it must use the ISO chronology.
*
* @param amount the temporal amount to convert, not null
* @return the equivalent period, not null
* @throws DateTimeException if unable to convert to a {@code Period}
* @throws ArithmeticException if the amount of years, months or days exceeds an int
*/
public static Period from(TemporalAmount amount) {
if (amount instanceof Period) {
return (Period) amount;
}
if (amount instanceof ChronoPeriod) {
if (IsoChronology.INSTANCE.equals(((ChronoPeriod) amount).getChronology()) == false) {
throw new DateTimeException("Period requires ISO chronology: " + amount);
}
}
Objects.requireNonNull(amount, "amount");
int years = 0;
int months = 0;
int days = 0;
for (TemporalUnit unit : amount.getUnits()) {
long unitAmount = amount.get(unit);
if (unit == ChronoUnit.YEARS) {
years = Math.toIntExact(unitAmount);
} else if (unit == ChronoUnit.MONTHS) {
months = Math.toIntExact(unitAmount);
} else if (unit == ChronoUnit.DAYS) {
days = Math.toIntExact(unitAmount);
} else {
throw new DateTimeException("Unit must be Years, Months or Days, but was " + unit);
}
}
return create(years, months, days);
}
//-----------------------------------------------------------------------
/**
* Obtains a {@code Period} from a text string such as {@code PnYnMnD}.
* <p>
* This will parse the string produced by {@code toString()} which is
* based on the ISO-8601 period formats {@code PnYnMnD} and {@code PnW}.
* <p>
* The string starts with an optional sign, denoted by the ASCII negative
* or positive symbol. If negative, the whole period is negated.
* The ASCII letter "P" is next in upper or lower case.
* There are then four sections, each consisting of a number and a suffix.
* At least one of the four sections must be present.
* The sections have suffixes in ASCII of "Y", "M", "W" and "D" for
* years, months, weeks and days, accepted in upper or lower case.
* The suffixes must occur in order.
* The number part of each section must consist of ASCII digits.
* The number may be prefixed by the ASCII negative or positive symbol.
* The number must parse to an {@code int}.
* <p>
* The leading plus/minus sign, and negative values for other units are
* not part of the ISO-8601 standard. In addition, ISO-8601 does not
* permit mixing between the {@code PnYnMnD} and {@code PnW} formats.
* Any week-based input is multiplied by 7 and treated as a number of days.
* <p>
* For example, the following are valid inputs:
* <pre>
* "P2Y" -- Period.ofYears(2)
* "P3M" -- Period.ofMonths(3)
* "P4W" -- Period.ofWeeks(4)
* "P5D" -- Period.ofDays(5)
* "P1Y2M3D" -- Period.of(1, 2, 3)
* "P1Y2M3W4D" -- Period.of(1, 2, 25)
* "P-1Y2M" -- Period.of(-1, 2, 0)
* "-P1Y2M" -- Period.of(-1, -2, 0)
* </pre>
*
* @param text the text to parse, not null
* @return the parsed period, not null
* @throws DateTimeParseException if the text cannot be parsed to a period
*/
public static Period parse(CharSequence text) {
Objects.requireNonNull(text, "text");
Matcher matcher = PATTERN.matcher(text);
if (matcher.matches()) {
int negate = ("-".equals(matcher.group(1)) ? -1 : 1);
String yearMatch = matcher.group(2);
String monthMatch = matcher.group(3);
String weekMatch = matcher.group(4);
String dayMatch = matcher.group(5);
if (yearMatch != null || monthMatch != null || dayMatch != null || weekMatch != null) {
try {
int years = parseNumber(text, yearMatch, negate);
int months = parseNumber(text, monthMatch, negate);
int weeks = parseNumber(text, weekMatch, negate);
int days = parseNumber(text, dayMatch, negate);
days = Math.addExact(days, Math.multiplyExact(weeks, 7));
return create(years, months, days);
} catch (NumberFormatException ex) {
throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0, ex);
}
}
}
throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0);
}
private static int parseNumber(CharSequence text, String str, int negate) {
if (str == null) {
return 0;
}
int val = Integer.parseInt(str);
try {
return Math.multiplyExact(val, negate);
} catch (ArithmeticException ex) {
throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0, ex);
}
}
//-----------------------------------------------------------------------
/**
* Obtains a {@code Period} consisting of the number of years, months,
* and days between two dates.
* <p>
* The start date is included, but the end date is not.
* The period is calculated by removing complete months, then calculating
* the remaining number of days, adjusting to ensure that both have the same sign.
* The number of months is then split into years and months based on a 12 month year.
* A month is considered if the end day-of-month is greater than or equal to the start day-of-month.
* For example, from {@code 2010-01-15} to {@code 2011-03-18} is one year, two months and three days.
* <p>
* The result of this method can be a negative period if the end is before the start.
* The negative sign will be the same in each of year, month and day.
*
* @param startDateInclusive the start date, inclusive, not null
* @param endDateExclusive the end date, exclusive, not null
* @return the period between this date and the end date, not null
* @see ChronoLocalDate#until(ChronoLocalDate)
*/
public static Period between(LocalDate startDateInclusive, LocalDate endDateExclusive) {
return startDateInclusive.until(endDateExclusive);
}
//-----------------------------------------------------------------------
/**
* Creates an instance.
*
* @param years the amount
* @param months the amount
* @param days the amount
*/
private static Period create(int years, int months, int days) {
if ((years | months | days) == 0) {
return ZERO;
}
return new Period(years, months, days);
}
/**
* Constructor.
*
* @param years the amount
* @param months the amount
* @param days the amount
*/
private Period(int years, int months, int days) {
this.years = years;
this.months = months;
this.days = days;
}
//-----------------------------------------------------------------------
/**
* Gets the value of the requested unit.
* <p>
* This returns a value for each of the three supported units,
* {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and
* {@link ChronoUnit#DAYS DAYS}.
* All other units throw an exception.
*
* @param unit the {@code TemporalUnit} for which to return the value
* @return the long value of the unit
* @throws DateTimeException if the unit is not supported
* @throws UnsupportedTemporalTypeException if the unit is not supported
*/
@Override
public long get(TemporalUnit unit) {
if (unit == ChronoUnit.YEARS) {
return getYears();
} else if (unit == ChronoUnit.MONTHS) {
return getMonths();
} else if (unit == ChronoUnit.DAYS) {
return getDays();
} else {
throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
}
}
/**
* Gets the set of units supported by this period.
* <p>
* The supported units are {@link ChronoUnit#YEARS YEARS},
* {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}.
* They are returned in the order years, months, days.
* <p>
* This set can be used in conjunction with {@link #get(TemporalUnit)}
* to access the entire state of the period.
*
* @return a list containing the years, months and days units, not null
*/
@Override
public List<TemporalUnit> getUnits() {
return SUPPORTED_UNITS;
}
/**
* Gets the chronology of this period, which is the ISO calendar system.
* <p>
* The {@code Chronology} represents the calendar system in use.
* The ISO-8601 calendar system is the modern civil calendar system used today
* in most of the world. It is equivalent to the proleptic Gregorian calendar
* system, in which today's rules for leap years are applied for all time.
*
* @return the ISO chronology, not null
*/
@Override
public IsoChronology getChronology() {
return IsoChronology.INSTANCE;
}
//-----------------------------------------------------------------------
/**
* Checks if all three units of this period are zero.
* <p>
* A zero period has the value zero for the years, months and days units.
*
* @return true if this period is zero-length
*/
public boolean isZero() {
return (this == ZERO);
}
/**
* Checks if any of the three units of this period are negative.
* <p>
* This checks whether the years, months or days units are less than zero.
*
* @return true if any unit of this period is negative
*/
public boolean isNegative() {
return years < 0 || months < 0 || days < 0;
}
//-----------------------------------------------------------------------
/**
* Gets the amount of years of this period.
* <p>
* This returns the years unit.
* <p>
* The months unit is not automatically normalized with the years unit.
* This means that a period of "15 months" is different to a period
* of "1 year and 3 months".
*
* @return the amount of years of this period, may be negative
*/
public int getYears() {
return years;
}
/**
* Gets the amount of months of this period.
* <p>
* This returns the months unit.
* <p>
* The months unit is not automatically normalized with the years unit.
* This means that a period of "15 months" is different to a period
* of "1 year and 3 months".
*
* @return the amount of months of this period, may be negative
*/
public int getMonths() {
return months;
}
/**
* Gets the amount of days of this period.
* <p>
* This returns the days unit.
*
* @return the amount of days of this period, may be negative
*/
public int getDays() {
return days;
}
//-----------------------------------------------------------------------
/**
* Returns a copy of this period with the specified amount of years.
* <p>
* This sets the amount of the years unit in a copy of this period.
* The months and days units are unaffected.
* <p>
* The months unit is not automatically normalized with the years unit.
* This means that a period of "15 months" is different to a period
* of "1 year and 3 months".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param years the years to represent, may be negative
* @return a {@code Period} based on this period with the requested years, not null
*/
public Period withYears(int years) {
if (years == this.years) {
return this;
}
return create(years, months, days);
}
/**
* Returns a copy of this period with the specified amount of months.
* <p>
* This sets the amount of the months unit in a copy of this period.
* The years and days units are unaffected.
* <p>
* The months unit is not automatically normalized with the years unit.
* This means that a period of "15 months" is different to a period
* of "1 year and 3 months".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param months the months to represent, may be negative
* @return a {@code Period} based on this period with the requested months, not null
*/
public Period withMonths(int months) {
if (months == this.months) {
return this;
}
return create(years, months, days);
}
/**
* Returns a copy of this period with the specified amount of days.
* <p>
* This sets the amount of the days unit in a copy of this period.
* The years and months units are unaffected.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param days the days to represent, may be negative
* @return a {@code Period} based on this period with the requested days, not null
*/
public Period withDays(int days) {
if (days == this.days) {
return this;
}
return create(years, months, days);
}
//-----------------------------------------------------------------------
/**
* Returns a copy of this period with the specified period added.
* <p>
* This operates separately on the years, months and days.
* No normalization is performed.
* <p>
* For example, "1 year, 6 months and 3 days" plus "2 years, 2 months and 2 days"
* returns "3 years, 8 months and 5 days".
* <p>
* The specified amount is typically an instance of {@code Period}.
* Other types are interpreted using {@link Period#from(TemporalAmount)}.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param amountToAdd the period to add, not null
* @return a {@code Period} based on this period with the requested period added, not null
* @throws DateTimeException if the specified amount has a non-ISO chronology or
* contains an invalid unit
* @throws ArithmeticException if numeric overflow occurs
*/
public Period plus(TemporalAmount amountToAdd) {
Period isoAmount = Period.from(amountToAdd);
return create(
Math.addExact(years, isoAmount.years),
Math.addExact(months, isoAmount.months),
Math.addExact(days, isoAmount.days));
}
/**
* Returns a copy of this period with the specified years added.
* <p>
* This adds the amount to the years unit in a copy of this period.
* The months and days units are unaffected.
* For example, "1 year, 6 months and 3 days" plus 2 years returns "3 years, 6 months and 3 days".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param yearsToAdd the years to add, positive or negative
* @return a {@code Period} based on this period with the specified years added, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period plusYears(long yearsToAdd) {
if (yearsToAdd == 0) {
return this;
}
return create(Math.toIntExact(Math.addExact(years, yearsToAdd)), months, days);
}
/**
* Returns a copy of this period with the specified months added.
* <p>
* This adds the amount to the months unit in a copy of this period.
* The years and days units are unaffected.
* For example, "1 year, 6 months and 3 days" plus 2 months returns "1 year, 8 months and 3 days".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param monthsToAdd the months to add, positive or negative
* @return a {@code Period} based on this period with the specified months added, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period plusMonths(long monthsToAdd) {
if (monthsToAdd == 0) {
return this;
}
return create(years, Math.toIntExact(Math.addExact(months, monthsToAdd)), days);
}
/**
* Returns a copy of this period with the specified days added.
* <p>
* This adds the amount to the days unit in a copy of this period.
* The years and months units are unaffected.
* For example, "1 year, 6 months and 3 days" plus 2 days returns "1 year, 6 months and 5 days".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param daysToAdd the days to add, positive or negative
* @return a {@code Period} based on this period with the specified days added, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period plusDays(long daysToAdd) {
if (daysToAdd == 0) {
return this;
}
return create(years, months, Math.toIntExact(Math.addExact(days, daysToAdd)));
}
//-----------------------------------------------------------------------
/**
* Returns a copy of this period with the specified period subtracted.
* <p>
* This operates separately on the years, months and days.
* No normalization is performed.
* <p>
* For example, "1 year, 6 months and 3 days" minus "2 years, 2 months and 2 days"
* returns "-1 years, 4 months and 1 day".
* <p>
* The specified amount is typically an instance of {@code Period}.
* Other types are interpreted using {@link Period#from(TemporalAmount)}.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param amountToSubtract the period to subtract, not null
* @return a {@code Period} based on this period with the requested period subtracted, not null
* @throws DateTimeException if the specified amount has a non-ISO chronology or
* contains an invalid unit
* @throws ArithmeticException if numeric overflow occurs
*/
public Period minus(TemporalAmount amountToSubtract) {
Period isoAmount = Period.from(amountToSubtract);
return create(
Math.subtractExact(years, isoAmount.years),
Math.subtractExact(months, isoAmount.months),
Math.subtractExact(days, isoAmount.days));
}
/**
* Returns a copy of this period with the specified years subtracted.
* <p>
* This subtracts the amount from the years unit in a copy of this period.
* The months and days units are unaffected.
* For example, "1 year, 6 months and 3 days" minus 2 years returns "-1 years, 6 months and 3 days".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param yearsToSubtract the years to subtract, positive or negative
* @return a {@code Period} based on this period with the specified years subtracted, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period minusYears(long yearsToSubtract) {
return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract));
}
/**
* Returns a copy of this period with the specified months subtracted.
* <p>
* This subtracts the amount from the months unit in a copy of this period.
* The years and days units are unaffected.
* For example, "1 year, 6 months and 3 days" minus 2 months returns "1 year, 4 months and 3 days".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param monthsToSubtract the years to subtract, positive or negative
* @return a {@code Period} based on this period with the specified months subtracted, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period minusMonths(long monthsToSubtract) {
return (monthsToSubtract == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-monthsToSubtract));
}
/**
* Returns a copy of this period with the specified days subtracted.
* <p>
* This subtracts the amount from the days unit in a copy of this period.
* The years and months units are unaffected.
* For example, "1 year, 6 months and 3 days" minus 2 days returns "1 year, 6 months and 1 day".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param daysToSubtract the months to subtract, positive or negative
* @return a {@code Period} based on this period with the specified days subtracted, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period minusDays(long daysToSubtract) {
return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-daysToSubtract));
}
//-----------------------------------------------------------------------
/**
* Returns a new instance with each element in this period multiplied
* by the specified scalar.
* <p>
* This returns a period with each of the years, months and days units
* individually multiplied.
* For example, a period of "2 years, -3 months and 4 days" multiplied by
* 3 will return "6 years, -9 months and 12 days".
* No normalization is performed.
*
* @param scalar the scalar to multiply by, not null
* @return a {@code Period} based on this period with the amounts multiplied by the scalar, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period multipliedBy(int scalar) {
if (this == ZERO || scalar == 1) {
return this;
}
return create(
Math.multiplyExact(years, scalar),
Math.multiplyExact(months, scalar),
Math.multiplyExact(days, scalar));
}
/**
* Returns a new instance with each amount in this period negated.
* <p>
* This returns a period with each of the years, months and days units
* individually negated.
* For example, a period of "2 years, -3 months and 4 days" will be
* negated to "-2 years, 3 months and -4 days".
* No normalization is performed.
*
* @return a {@code Period} based on this period with the amounts negated, not null
* @throws ArithmeticException if numeric overflow occurs, which only happens if
* one of the units has the value {@code Long.MIN_VALUE}
*/
public Period negated() {
return multipliedBy(-1);
}
//-----------------------------------------------------------------------
/**
* Returns a copy of this period with the years and months normalized.
* <p>
* This normalizes the years and months units, leaving the days unit unchanged.
* The months unit is adjusted to have an absolute value less than 11,
* with the years unit being adjusted to compensate. For example, a period of
* "1 Year and 15 months" will be normalized to "2 years and 3 months".
* <p>
* The sign of the years and months units will be the same after normalization.
* For example, a period of "1 year and -25 months" will be normalized to
* "-1 year and -1 month".
* <p>
* This instance is immutable and unaffected by this method call.
*
* @return a {@code Period} based on this period with excess months normalized to years, not null
* @throws ArithmeticException if numeric overflow occurs
*/
public Period normalized() {
long totalMonths = toTotalMonths();
long splitYears = totalMonths / 12;
int splitMonths = (int) (totalMonths % 12); // no overflow
if (splitYears == years && splitMonths == months) {
return this;
}
return create(Math.toIntExact(splitYears), splitMonths, days);
}
/**
* Gets the total number of months in this period.
* <p>
* This returns the total number of months in the period by multiplying the
* number of years by 12 and adding the number of months.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @return the total number of months in the period, may be negative
*/
public long toTotalMonths() {
return years * 12L + months; // no overflow
}
//-------------------------------------------------------------------------
/**
* Adds this period to the specified temporal object.
* <p>
* This returns a temporal object of the same observable type as the input
* with this period added.
* If the temporal has a chronology, it must be the ISO chronology.
* <p>
* In most cases, it is clearer to reverse the calling pattern by using
* {@link Temporal#plus(TemporalAmount)}.
* <pre>
* // these two lines are equivalent, but the second approach is recommended
* dateTime = thisPeriod.addTo(dateTime);
* dateTime = dateTime.plus(thisPeriod);
* </pre>
* <p>
* The calculation operates as follows.
* First, the chronology of the temporal is checked to ensure it is ISO chronology or null.
* Second, if the months are zero, the years are added if non-zero, otherwise
* the combination of years and months is added if non-zero.
* Finally, any days are added.
* <p>
* This approach ensures that a partial period can be added to a partial date.
* For example, a period of years and/or months can be added to a {@code YearMonth},
* but a period including days cannot.
* The approach also adds years and months together when necessary, which ensures
* correct behaviour at the end of the month.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param temporal the temporal object to adjust, not null
* @return an object of the same type with the adjustment made, not null
* @throws DateTimeException if unable to add
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
public Temporal addTo(Temporal temporal) {
validateChrono(temporal);
if (months == 0) {
if (years != 0) {
temporal = temporal.plus(years, YEARS);
}
} else {
long totalMonths = toTotalMonths();
if (totalMonths != 0) {
temporal = temporal.plus(totalMonths, MONTHS);
}
}
if (days != 0) {
temporal = temporal.plus(days, DAYS);
}
return temporal;
}
/**
* Subtracts this period from the specified temporal object.
* <p>
* This returns a temporal object of the same observable type as the input
* with this period subtracted.
* If the temporal has a chronology, it must be the ISO chronology.
* <p>
* In most cases, it is clearer to reverse the calling pattern by using
* {@link Temporal#minus(TemporalAmount)}.
* <pre>
* // these two lines are equivalent, but the second approach is recommended
* dateTime = thisPeriod.subtractFrom(dateTime);
* dateTime = dateTime.minus(thisPeriod);
* </pre>
* <p>
* The calculation operates as follows.
* First, the chronology of the temporal is checked to ensure it is ISO chronology or null.
* Second, if the months are zero, the years are subtracted if non-zero, otherwise
* the combination of years and months is subtracted if non-zero.
* Finally, any days are subtracted.
* <p>
* This approach ensures that a partial period can be subtracted from a partial date.
* For example, a period of years and/or months can be subtracted from a {@code YearMonth},
* but a period including days cannot.
* The approach also subtracts years and months together when necessary, which ensures
* correct behaviour at the end of the month.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param temporal the temporal object to adjust, not null
* @return an object of the same type with the adjustment made, not null
* @throws DateTimeException if unable to subtract
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
public Temporal subtractFrom(Temporal temporal) {
validateChrono(temporal);
if (months == 0) {
if (years != 0) {
temporal = temporal.minus(years, YEARS);
}
} else {
long totalMonths = toTotalMonths();
if (totalMonths != 0) {
temporal = temporal.minus(totalMonths, MONTHS);
}
}
if (days != 0) {
temporal = temporal.minus(days, DAYS);
}
return temporal;
}
/**
* Validates that the temporal has the correct chronology.
*/
private void validateChrono(TemporalAccessor temporal) {
Objects.requireNonNull(temporal, "temporal");
Chronology temporalChrono = temporal.query(TemporalQueries.chronology());
if (temporalChrono != null && IsoChronology.INSTANCE.equals(temporalChrono) == false) {
throw new DateTimeException("Chronology mismatch, expected: ISO, actual: " + temporalChrono.getId());
}
}
//-----------------------------------------------------------------------
/**
* Checks if this period is equal to another period.
* <p>
* The comparison is based on the type {@code Period} and each of the three amounts.
* To be equal, the years, months and days units must be individually equal.
* Note that this means that a period of "15 Months" is not equal to a period
* of "1 Year and 3 Months".
*
* @param obj the object to check, null returns false
* @return true if this is equal to the other period
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof Period) {
Period other = (Period) obj;
return years == other.years &&
months == other.months &&
days == other.days;
}
return false;
}
/**
* A hash code for this period.
*
* @return a suitable hash code
*/
@Override
public int hashCode() {
return years + Integer.rotateLeft(months, 8) + Integer.rotateLeft(days, 16);
}
//-----------------------------------------------------------------------
/**
* Outputs this period as a {@code String}, such as {@code P6Y3M1D}.
* <p>
* The output will be in the ISO-8601 period format.
* A zero period will be represented as zero days, 'P0D'.
*
* @return a string representation of this period, not null
*/
@Override
public String toString() {
if (this == ZERO) {
return "P0D";
} else {
StringBuilder buf = new StringBuilder();
buf.append('P');
if (years != 0) {
buf.append(years).append('Y');
}
if (months != 0) {
buf.append(months).append('M');
}
if (days != 0) {
buf.append(days).append('D');
}
return buf.toString();
}
}
//-----------------------------------------------------------------------
/**
* Writes the object using a
* <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form.
* @serialData
* <pre>
* out.writeByte(14); // identifies a Period
* out.writeInt(years);
* out.writeInt(months);
* out.writeInt(days);
* </pre>
*
* @return the instance of {@code Ser}, not null
*/
private Object writeReplace() {
return new Ser(Ser.PERIOD_TYPE, this);
}
/**
* Defend against malicious streams.
*
* @throws java.io.InvalidObjectException always
*/
private void readObject(ObjectInputStream s) throws InvalidObjectException {
throw new InvalidObjectException("Deserialization via serialization delegate");
}
void writeExternal(DataOutput out) throws IOException {
out.writeInt(years);
out.writeInt(months);
out.writeInt(days);
}
static Period readExternal(DataInput in) throws IOException {
int years = in.readInt();
int months = in.readInt();
int days = in.readInt();
return Period.of(years, months, days);
}
}
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