Re: How can I use Operand (+ , - ) with Time

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 15 Jan 2012 10:31:21 -0800
Message-ID:
<jev61p$eh7$1@news.albasani.net>
On 01/15/2012 04:51 AM, Stefan Ram wrote:

sahm<sahm007@gmail.com> writes:

But how can I use operand (+, -) with Time


   You need to find or implement a compiler or interpreter for
   a language that supports operator overloading (Java does not).

   Or, convert all times into values of the primitive Java data
   type ??double?? (such as a count of seconds) and then used ??+??
   with those double values.


That tends to cause trouble. It's better to use 'java.util.Calendar' and its
friends prior to Java 7, and the new time types for 7+.

The application apparently tracks working hours. How much overtime does
someone in New York get who works eight hours nornmally but works from
midnight to eight a.m. on November 4, 2012?

Naive calculations based on double or int values for number of seconds in an
hour will give you the wrong answer. To get the right answer across all
possible dates and locales (e.g., March 25, 2012, in London, UK), you will
need all kinds of complicated calculation. Heck, just to get the right number
of days in February (say, year 2100) requires some dancing.

Tou will note that the OP's example committed this error.

Why in the heck would you recommend 'double' as a time, date or interval type?
  It's very inappropriate.

--
Lew
Honi soit qui mal y pense.
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