+ * 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