* 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. * *
* 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.doGet()' assumes the same value from * midnight until just before the next midnight. * When 'JULIAN_DAY.doWith()' is applied to a date-time, the time of day portion remains unaltered. * 'JULIAN_DAY.doWith()' and 'JULIAN_DAY.doGet()' only apply to {@code Temporal} objects that * can be converted into {@link ChronoField#EPOCH_DAY}. * A {@link DateTimeException} is thrown for any other type of object. *
*
*
* | 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 = new Field("JulianDay", DAYS, FOREVER, JULIAN_DAY_OFFSET); /** * 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.doGet()' assumes the same value from * midnight until just before the next midnight. * When 'MODIFIED_JULIAN_DAY.doWith()' is applied to a date-time, the time of day portion remains unaltered. * 'MODIFIED_JULIAN_DAY.doWith()' and 'MODIFIED_JULIAN_DAY.doGet()' only apply to {@code Temporal} objects * that can be converted into {@link ChronoField#EPOCH_DAY}. * A {@link DateTimeException} is thrown for any other type of object. *
* This implementation is an integer version of MJD with the decimal part rounded to floor. *
*
* | 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 = new Field("ModifiedJulianDay", DAYS, FOREVER, 40587L); /** * 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.doGet()' assumes the same value from
* midnight until just before the next midnight.
* When 'RATA_DIE.doWith()' is applied to a date-time, the time of day portion remains unaltered.
* 'MODIFIED_JULIAN_DAY.doWith()' and 'RATA_DIE.doGet()' only apply to {@code Temporal} objects
* that can be converted into {@link ChronoField#EPOCH_DAY}.
* A {@link DateTimeException} is thrown for any other type of object.
*/
public static final TemporalField RATA_DIE = new Field("RataDie", DAYS, FOREVER, 719163L);
/**
* Restricted constructor.
*/
private JulianFields() {
throw new AssertionError("Not instantiable");
}
/**
* implementation of JulianFields. Each instance is a singleton.
*/
private static class Field implements TemporalField, Serializable {
private static final long serialVersionUID = -7501623920830201812L;
private final 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;
}
/**
* Resolve the object from the stream to the appropriate singleton.
* @return one of the singleton objects {@link #JULIAN_DAY},
* {@link #MODIFIED_JULIAN_DAY}, or {@link #RATA_DIE}.
* @throws InvalidObjectException if the object in the stream is not one of the singletons.
*/
private Object readResolve() throws InvalidObjectException {
if (JULIAN_DAY.getName().equals(name)) {
return JULIAN_DAY;
} else if (MODIFIED_JULIAN_DAY.getName().equals(name)) {
return MODIFIED_JULIAN_DAY;
} else if (RATA_DIE.getName().equals(name)) {
return RATA_DIE;
} else {
throw new InvalidObjectException("Not one of the singletons");
}
}
//-----------------------------------------------------------------------
@Override
public String getName() {
return name;
}
@Override
public TemporalUnit getBaseUnit() {
return baseUnit;
}
@Override
public TemporalUnit getRangeUnit() {
return rangeUnit;
}
@Override
public ValueRange range() {
return range;
}
//-----------------------------------------------------------------------
@Override
public boolean doIsSupported(TemporalAccessor temporal) {
return temporal.isSupported(EPOCH_DAY);
}
@Override
public ValueRange doRange(TemporalAccessor temporal) {
if (doIsSupported(temporal) == false) {
throw new DateTimeException("Unsupported field: " + this);
}
return range();
}
@Override
public long doGet(TemporalAccessor temporal) {
return temporal.getLong(EPOCH_DAY) + offset;
}
@Override
public