Java date function

[Nemeliza]

How do you call this function. I am trying to calculate the time taken to perform a calculation, here is my cut down pseudo.

date_before = current_date;

PERFORM CALCULATION

time_taken = current_date - date_before;

HEEEEEEEEEEEELP?!

I know theres a built in date function but i dont know how to call it.

[Spunkey]

hi matey!

I've just had to do something similar myself, and being a VB/ASP programmer by trade i though JS would have some kind of datediff function, but it doesnt!! (AFAIK, could be wrong)

however if you can do this....

 dBeforeDate = Date.parse(todays_date)

 .. Do Some Stuff

 dAfterDate = Date.parse(todays_date)

  iTimeTaken = dAfterDate - dBeforeDate // in milliseconds

the date.parse will return an integer of the number of milliseconds elapsed since the given date and the 1st of January 1970 - i kid ye not.

anyhoo, you can work out the seconds/minutes from the returned iTimeTaken.

HTH!

[killgORE]

That is a good suggestion. However, I think you might need a pointer to the API for this one.

http://java.sun.com/j2se/1.4.2/docs/api/index.html

Look at that for the roots of the rest of this reply. The java API is your friend.

the algorithm should be something like...

long timeOneInMilliSeconds = new Date().getTime() ; // this makes a new Date object and then sets the long integer value of the Date object (milliseconds since january 1st 1970 - a unix legacy idea) into the timeOneInMilliSeconds variable..

// Do lots of funky and useful things

long timeTwoInMilliSeconds = new Date().getTime() ; // this makes a new Date object and then sets the long integer value of the Date object into the timeTwoInMilliSeconds variable..

long difference = timeTwoInMilliSeconds - timeOneInMilliSeconds ;
..........

Then to get the difference in a useful form.. Like a Date obeject. Do something like the following.

Date useful = new Date(difference) ; // This is a constructor for the Date object where the parameter is a long integer.
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hope that helps bud

[dgr]

How do you call this function. I am trying to calculate the time taken to perform a calculation, here is my cut down pseudo.

date_before = current_date;

PERFORM CALCULATION

time_taken = current_date - date_before;

HEEEEEEEEEEEELP?!

I know theres a built in date function but i dont know how to call it.

word of warning, java developers prefer if your variables are named dateBefore, currentDate, timeTaken, etc. Your classes should be called FruitClass, VehiclesAndAnimals, etc.

[DsW]

I find the System.currentTimeMillis() useful for timing things.

e.g.

long startTime = System.currentTimeMillis();
doStuff();
long endTime = System.currentTimeMillis();
System.out.println("Time taken = "+(endTime-startTime)+"ms");

cheers,
dave

[Nemeliza]

Thanks got it going.