/**
* Creates a <code>Years</code> representing the number of whole years between the two specified
* partial datetimes.
*
* <p>The two partials must contain the same fields, for example you can specify two <code>
* LocalDate</code> objects.
*
* @param start the start partial date, must not be null
* @param end the end partial date, must not be null
* @return the period in years
* @throws IllegalArgumentException if the partials are null or invalid
*/
public static Years yearsBetween(ReadablePartial start, ReadablePartial end) {
if (start instanceof LocalDate && end instanceof LocalDate) {
Chronology chrono = DateTimeUtils.getChronology(start.getChronology());
int years =
chrono
.years()
.getDifference(
((LocalDate) end).getLocalMillis(), ((LocalDate) start).getLocalMillis());
return Years.years(years);
}
int amount = BaseSingleFieldPeriod.between(start, end, ZERO);
return Years.years(amount);
}
/**
* Creates a new <code>Years</code> by parsing a string in the ISO8601 format 'PnY'.
*
* <p>The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the years
* component may be non-zero. If any other component is non-zero, an exception will be thrown.
*
* @param periodStr the period string, null returns zero
* @return the period in years
* @throws IllegalArgumentException if the string format is invalid
*/
public static Years parseYears(String periodStr) {
if (periodStr == null) {
return Years.ZERO;
}
Period p = PARSER.parsePeriod(periodStr);
return Years.years(p.getYears());
}
/**
* Creates a <code>Years</code> representing the number of whole years in the specified interval.
* This method corectly handles any daylight savings time changes that may occur during the
* interval.
*
* @param interval the interval to extract years from, null returns zero
* @return the period in years
* @throws IllegalArgumentException if the partials are null or invalid
*/
public static Years yearsIn(ReadableInterval interval) {
if (interval == null) {
return Years.ZERO;
}
int amount =
BaseSingleFieldPeriod.between(
interval.getStart(), interval.getEnd(), DurationFieldType.years());
return Years.years(amount);
}
/**
* Creates a <code>Years</code> representing the number of whole years between the two specified
* datetimes. This method corectly handles any daylight savings time changes that may occur during
* the interval.
*
* @param start the start instant, must not be null
* @param end the end instant, must not be null
* @return the period in years
* @throws IllegalArgumentException if the instants are null or invalid
*/
public static Years yearsBetween(ReadableInstant start, ReadableInstant end) {
int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.years());
return Years.years(amount);
}
/**
* Returns a new instance with the years value negated.
*
* @return the new period with a negated value
* @throws ArithmeticException if the result overflows an int
*/
public Years negated() {
return Years.years(FieldUtils.safeNegate(getValue()));
}
/**
* Returns a new instance with the years divided by the specified divisor. The calculation uses
* integer division, thus 3 divided by 2 is 1.
*
* <p>This instance is immutable and unaffected by this method call.
*
* @param divisor the amount to divide by, may be negative
* @return the new period divided by the specified divisor
* @throws ArithmeticException if the divisor is zero
*/
public Years dividedBy(int divisor) {
if (divisor == 1) {
return this;
}
return Years.years(getValue() / divisor);
}
/**
* Returns a new instance with the years multiplied by the specified scalar.
*
* <p>This instance is immutable and unaffected by this method call.
*
* @param scalar the amount to multiply by, may be negative
* @return the new period multiplied by the specified scalar
* @throws ArithmeticException if the result overflows an int
*/
public Years multipliedBy(int scalar) {
return Years.years(FieldUtils.safeMultiply(getValue(), scalar));
}
/**
* Returns a new instance with the specified number of years added.
*
* <p>This instance is immutable and unaffected by this method call.
*
* @param years the amount of years to add, may be negative
* @return the new period plus the specified number of years
* @throws ArithmeticException if the result overflows an int
*/
public Years plus(int years) {
if (years == 0) {
return this;
}
return Years.years(FieldUtils.safeAdd(getValue(), years));
}
/**
* Resolves singletons.
*
* @return the singleton instance
*/
private Object readResolve() {
return Years.years(getValue());
}