org.esa.beam.util
Class DateTimeUtils

java.lang.Object
  org.esa.beam.util.DateTimeUtils

public class DateTimeUtils
extends Object

This utility class provides some date/time related methods.

Version:

$Revision$ $Date$

Author:

Norman Fomferra

See Also:

Date

Field Summary

static double	HOURS_PER_DAY The number of hours per day.
static SimpleDateFormat	ISO_8601_FORMAT An ISO 8601 date/time format.
static double	JD_OFFSET The number of days from noon Jan 1, 4713 BC (Proleptic Julian) to midnight 1/1/1970 AD (Gregorian).
static double	MICROS_PER_DAY The number of micro-seconds per day.
static double	MILLIS_PER_DAY The number of milli-seconds per day.
static double	MJD_OFFSET The Modified Julian Day (MJD) gives the number of days since midnight on November 17, 1858.
static double	SECONDS_PER_DAY The number of seconds per day.

Constructor Summary

DateTimeUtils()

Method Summary

static double	jdToMJD(double jd) Converts a julian day (JD) to a modified julian day (MJD) value.
static Date	jdToUTC(double jd) Converts a julian day (JD) to a UTC date/time value.
static double	mjdToJD(double mjd) Converts a modified julian day (MJD) to a julian day (JD) value.
static Date	stringToUTC(String utc) Converts a UTC date/time string to a UTC date/time value.
static double	utcToJD(Date utc) Converts a UTC date/time value to a julian day (JD).
static String	utcToString(Date utc) Converts a UTC date/time value to a string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ISO_8601_FORMAT

public static final SimpleDateFormat ISO_8601_FORMAT

An ISO 8601 date/time format.

JD_OFFSET

public static final double JD_OFFSET

The number of days from noon Jan 1, 4713 BC (Proleptic Julian) to midnight 1/1/1970 AD (Gregorian). 1/1/1970 is time zero for a java.util.Date.

See Also:

Constant Field Values

MJD_OFFSET

public static final double MJD_OFFSET

The Modified Julian Day (MJD) gives the number of days since midnight on November 17, 1858. This date corresponds to MJD_OFFSET = 2400000.5 days after day zero of the Julian calendar.

See Also:

Constant Field Values

HOURS_PER_DAY

public static final double HOURS_PER_DAY

The number of hours per day.

See Also:

Constant Field Values

SECONDS_PER_DAY

public static final double SECONDS_PER_DAY

The number of seconds per day.

See Also:

Constant Field Values

MILLIS_PER_DAY

public static final double MILLIS_PER_DAY

The number of milli-seconds per day.

See Also:

Constant Field Values

MICROS_PER_DAY

public static final double MICROS_PER_DAY

The number of micro-seconds per day.

See Also:

Constant Field Values

Constructor Detail

DateTimeUtils

public DateTimeUtils()

Method Detail

jdToMJD

public static double jdToMJD(double jd)

Converts a julian day (JD) to a modified julian day (MJD) value.

Parameters:

jd - the julian day

Returns:

the modified julian day

mjdToJD

public static double mjdToJD(double mjd)

Converts a modified julian day (MJD) to a julian day (JD) value.

Parameters:

mjd - the modified julian day

Returns:

the julian day

jdToUTC

public static Date jdToUTC(double jd)

Converts a julian day (JD) to a UTC date/time value.

Important note: Due to the limitations of java.util.Date this method does not take leap seconds into account.

Parameters:

jd - the julian day

Returns:

the UTC date/time

utcToJD

public static double utcToJD(Date utc)

Converts a UTC date/time value to a julian day (JD).

Important note: Due to the limitations of java.util.Date this method does not take leap seconds into account.

Parameters:

utc - the UTC date/time, if null the current time is converted

Returns:

the julian day

utcToString

public static String utcToString(Date utc)

Converts a UTC date/time value to a string. The method uses the ISO 8601 date/time format YYYY-MM-DD hh:mm:ss.S

Important note: Due to the limitations of java.util.Date this method does not take leap seconds into account.

Parameters:

utc - the UTC date/time value

Returns:

the UTC date/time string

stringToUTC

public static Date stringToUTC(String utc)
                        throws ParseException

Converts a UTC date/time string to a UTC date/time value. The method uses the ISO 8601 date/time format YYYY-MM-DD hh:mm:ss.S

Important note: Due to the limitations of java.util.Date this method does not take leap seconds into account.

Parameters:

utc - the UTC date/time string

Throws:

ParseException