* The Julian Day is a standard way of expressing date and time commonly used in the scientific community. * It is expressed as a decimal number of whole days where days start at midday. * This class represents variations on Julian Days that count whole days from midnight. *
* The fields are implemented relative to {@link ChronoField#EPOCH_DAY EPOCH_DAY}. * The fields are supported, and can be queried and set if {@code EPOCH_DAY} is available. * The fields work with all chronologies. * * @implSpec * This is an immutable and thread-safe class. * * @since 1.8 */ public final class JulianFields { /** * The offset from Julian to EPOCH DAY. */ private static final long JULIAN_DAY_OFFSET = 2440588L; /** * Julian Day field. *
* This is an integer-based version of the Julian Day Number. * Julian Day is a well-known system that represents the count of whole days since day 0, * which is defined to be January 1, 4713 BCE in the Julian calendar, and -4713-11-24 Gregorian. * The field has "JulianDay" as 'name', and 'DAYS' as 'baseUnit'. * The field always refers to the local date-time, ignoring the offset or zone. *
* For date-times, 'JULIAN_DAY.getFrom()' assumes the same value from * midnight until just before the next midnight. * When 'JULIAN_DAY.adjustInto()' is applied to a date-time, the time of day portion remains unaltered. * 'JULIAN_DAY.adjustInto()' and 'JULIAN_DAY.getFrom()' only apply to {@code Temporal} objects that * can be converted into {@link ChronoField#EPOCH_DAY}. * An {@link UnsupportedTemporalTypeException} is thrown for any other type of object. *
* In the resolving phase of parsing, a date can be created from a Julian Day field. * In {@linkplain ResolverStyle#STRICT strict mode} and {@linkplain ResolverStyle#SMART smart mode} * the Julian Day value is validated against the range of valid values. * In {@linkplain ResolverStyle#LENIENT lenient mode} no validation occurs. * *
* By contrast, this implementation has no fractional part, and counts * days from midnight to midnight. * This implementation uses an integer and days starting at midnight. * The integer value for the Julian Day Number is the astronomical Julian Day value at midday * of the date in question. * This amounts to the astronomical Julian Day, rounded to an integer {@code JDN = floor(JD + 0.5)}. * *
* | ISO date | Julian Day Number | Astronomical Julian Day |
* | 1970-01-01T00:00 | 2,440,588 | 2,440,587.5 |
* | 1970-01-01T06:00 | 2,440,588 | 2,440,587.75 |
* | 1970-01-01T12:00 | 2,440,588 | 2,440,588.0 |
* | 1970-01-01T18:00 | 2,440,588 | 2,440,588.25 |
* | 1970-01-02T00:00 | 2,440,589 | 2,440,588.5 |
* | 1970-01-02T06:00 | 2,440,589 | 2,440,588.75 |
* | 1970-01-02T12:00 | 2,440,589 | 2,440,589.0 |
*
* * Julian Days are sometimes taken to imply Universal Time or UTC, but this * implementation always uses the Julian Day number for the local date, * regardless of the offset or time-zone. */ public static final TemporalField JULIAN_DAY = Field.JULIAN_DAY; /** * Modified Julian Day field. *
* This is an integer-based version of the Modified Julian Day Number. * Modified Julian Day (MJD) is a well-known system that counts days continuously. * It is defined relative to astronomical Julian Day as {@code MJD = JD - 2400000.5}. * Each Modified Julian Day runs from midnight to midnight. * The field always refers to the local date-time, ignoring the offset or zone. *
* For date-times, 'MODIFIED_JULIAN_DAY.getFrom()' assumes the same value from * midnight until just before the next midnight. * When 'MODIFIED_JULIAN_DAY.adjustInto()' is applied to a date-time, the time of day portion remains unaltered. * 'MODIFIED_JULIAN_DAY.adjustInto()' and 'MODIFIED_JULIAN_DAY.getFrom()' only apply to {@code Temporal} objects * that can be converted into {@link ChronoField#EPOCH_DAY}. * An {@link UnsupportedTemporalTypeException} is thrown for any other type of object. *
* This implementation is an integer version of MJD with the decimal part rounded to floor. *
* In the resolving phase of parsing, a date can be created from a Modified Julian Day field. * In {@linkplain ResolverStyle#STRICT strict mode} and {@linkplain ResolverStyle#SMART smart mode} * the Modified Julian Day value is validated against the range of valid values. * In {@linkplain ResolverStyle#LENIENT lenient mode} no validation occurs. * *
* | ISO date | Modified Julian Day | Decimal MJD |
* | 1970-01-01T00:00 | 40,587 | 40,587.0 |
* | 1970-01-01T06:00 | 40,587 | 40,587.25 |
* | 1970-01-01T12:00 | 40,587 | 40,587.5 |
* | 1970-01-01T18:00 | 40,587 | 40,587.75 |
* | 1970-01-02T00:00 | 40,588 | 40,588.0 |
* | 1970-01-02T06:00 | 40,588 | 40,588.25 |
* | 1970-01-02T12:00 | 40,588 | 40,588.5 |
*
*
* Modified Julian Days are sometimes taken to imply Universal Time or UTC, but this
* implementation always uses the Modified Julian Day for the local date,
* regardless of the offset or time-zone.
*/
public static final TemporalField MODIFIED_JULIAN_DAY = Field.MODIFIED_JULIAN_DAY;
/**
* Rata Die field.
* * Rata Die counts whole days continuously starting day 1 at midnight at the beginning of 0001-01-01 (ISO). * The field always refers to the local date-time, ignoring the offset or zone. *
* For date-times, 'RATA_DIE.getFrom()' assumes the same value from * midnight until just before the next midnight. * When 'RATA_DIE.adjustInto()' is applied to a date-time, the time of day portion remains unaltered. * 'RATA_DIE.adjustInto()' and 'RATA_DIE.getFrom()' only apply to {@code Temporal} objects * that can be converted into {@link ChronoField#EPOCH_DAY}. * An {@link UnsupportedTemporalTypeException} is thrown for any other type of object. *
* In the resolving phase of parsing, a date can be created from a Rata Die field.
* In {@linkplain ResolverStyle#STRICT strict mode} and {@linkplain ResolverStyle#SMART smart mode}
* the Rata Die value is validated against the range of valid values.
* In {@linkplain ResolverStyle#LENIENT lenient mode} no validation occurs.
*/
public static final TemporalField RATA_DIE = Field.RATA_DIE;
/**
* Restricted constructor.
*/
private JulianFields() {
throw new AssertionError("Not instantiable");
}
/**
* Implementation of JulianFields. Each instance is a singleton.
*/
private static enum Field implements TemporalField {
JULIAN_DAY("JulianDay", DAYS, FOREVER, JULIAN_DAY_OFFSET),
MODIFIED_JULIAN_DAY("ModifiedJulianDay", DAYS, FOREVER, 40587L),
RATA_DIE("RataDie", DAYS, FOREVER, 719163L);
private static final long serialVersionUID = -7501623920830201812L;
private final transient String name;
private final transient TemporalUnit baseUnit;
private final transient TemporalUnit rangeUnit;
private final transient ValueRange range;
private final transient long offset;
private Field(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, long offset) {
this.name = name;
this.baseUnit = baseUnit;
this.rangeUnit = rangeUnit;
this.range = ValueRange.of(-365243219162L + offset, 365241780471L + offset);
this.offset = offset;
}
//-----------------------------------------------------------------------
@Override
public TemporalUnit getBaseUnit() {
return baseUnit;
}
@Override
public TemporalUnit getRangeUnit() {
return rangeUnit;
}
@Override
public boolean isDateBased() {
return true;
}
@Override
public boolean isTimeBased() {
return false;
}
@Override
public ValueRange range() {
return range;
}
//-----------------------------------------------------------------------
@Override
public boolean isSupportedBy(TemporalAccessor temporal) {
return temporal.isSupported(EPOCH_DAY);
}
@Override
public ValueRange rangeRefinedBy(TemporalAccessor temporal) {
if (isSupportedBy(temporal) == false) {
throw new DateTimeException("Unsupported field: " + this);
}
return range();
}
@Override
public long getFrom(TemporalAccessor temporal) {
return temporal.getLong(EPOCH_DAY) + offset;
}
@SuppressWarnings("unchecked")
@Override
public