Tutorials 4.4 Dates

Tutorials 4.4 Dates

What is a date ?

A date is an instance of AbsoluteDate. Two important things are necessary to know:

• It is an immutable object, meaning, once it is created, it is no more possible to change it. If you want, for example to shift it, you will have to create a new date, eventually starting from the initial one using the shiftedBy() method;
• It is allways "stored" in the TAI time scale (but may be built and/or expressed in other formats). Time scales are available with a factory (TimeScalesFactory.getXXX()). But, be careful that it is mandatory to use a PATRIUS data set as UTC/TAI shifts are stored in it !

Some basic operations may be executed as, for example, comparizon (compareTo()), computing a duration (durationFrom()), adding an offset (shiftedBy()) ...

Code example: create dates