How do I figure out whether the current time is in between two times?

Question

I'm trying to write a schedule program in Java and I need to figure out what time it is, and whether the current time is in between two set times. Figuring out the current time is pretty simple, but do you have any suggestions for figuring out whether it is between two times of day. For example, it is 9:33 AM on a Thursday. So I would need to figure out which scheduled section of the week that time corresponds to. How would I go about comparing the time to set periods during the week, for example an Array of sectioned times during a week such as {Monday from 9-10 AM, Tuesday from 3-4 PM, Thursday from 8-11 AM}, and seeing which section of time the current time falls between?

Well if you timespans are stored that way "Monday from 9-10AM" , you'll have to write your own parser to extract valid datetime variables from that string. Then you can compare with the actual time/date — Laurent S., Sep 12 '13 at 13:38
Can you show some code you already have? How are you getting the current time? What does the one you want to compare against look like? — André Stannek, Sep 12 '13 at 13:39
Joda time might be able to help you with this. Take a look: http://www.joda.org/joda-time/ — Ben Dale, Sep 12 '13 at 13:52

JGutierrezC · Answer 1 · 2013-09-12T14:00:42.257

If you're using Date Class, you could do it like this

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm");
Date before = sdf.parse("07/05/2012 08:00");
Date after = sdf.parse("07/05/2012 08:30");
Date toCheck = sdf.parse("07/05/2012 08:15");
//is toCheck between the two?
boolean isAvailable = (before.getTime() < toCheck.getTime()) && after.getTime() > toCheck.getTime();

EDITED

As suggested by Jonathan Drapeau you could also use compareTo.

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm");
Date before = sdf.parse("07/05/2012 08:00");
Date after = sdf.parse("07/05/2012 08:30");
Date toCheck = sdf.parse("07/05/2012 08:15");
//is toCheck between the two?

if you want to include the "initial" and "final" date range

boolean isAvailable = before.compareTo(toCheck) >= 0 && after.compareTo(toCheck) <= 0

if you want to exclude the "initial" and "final" date range

boolean isAvailable = before.compareTo(toCheck) > 0 && after.compareTo(toCheck) < 0

You could use it too on Calendar class.

Anyway, i highly recommend you to use Calendar. It's a way precise class

you could check it like this:

Calendar cal1 = Calendar.getInstance(); // for example 12:00:00
Calendar cal2 = Calendar.getInstance(); // for exmaple 12:30:00
Calendar userTime = Calendar.getInstance(); // time to test: 12:15:00

if(user.after(cal1)&& user.before(cal2)){
    //... 
}

And to initialize and set times to Calendar, check this:

http://www.tutorialspoint.com/java/util/calendar_settime.htm

using `compareTo` on the `Date`s would work and be as readable if not more. — Jonathan Drapeau, Sep 12 '13 at 13:52

Qwerky · Answer 2 · 2013-09-12T13:52:24.170

3

An efficient way to find which period any date lies within would be to have a class;

public class TimePeriod implements Comparable<TimePeriod>{

  Date start;
  Date end;

  //Constructor, getters, setters

  boolean isIn(Date date) {
    return date.after(start) && date.before(end);
  }

  public int compareTo(TimePeriod other) {
    return start.compareTo(other.start);
  }
}

..and then create a sorted list of TimePeriod where you can perform a binary search.

edit:
This might make the binary search easier;

int check(Date date) {
  if (isIn(date)) {
    return 0;
  } else if (start.after(date)) {
    return -1;
  } else if (end.before(date)) {
    return 1;
  } else {
    throw new IllegalStateException("Time has gone badly wrong");
  }
}

edited Sep 12 '13 at 13:52

answered Sep 12 '13 at 13:44

Qwerky

18,217
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@JonathanDrapeau - couldn't disagree more, what could be more simple to understand than 'after' and 'before'? – Qwerky Sep 12 '13 at 13:55
@JonathanDrapeau if you're talking about the `check` method you can't use a single `compareTo` as you're comparing the `date` to the `start` *and* `end` dates. – Qwerky Sep 12 '13 at 14:00

score 2 · Answer 3 · answered Sep 12 '13 at 13:43

I would suggest using the Epoch time.

For a definition of Epoch time: http://en.wikipedia.org/wiki/Epoch_time

Basically, its a number of seconds after a specific date, i believe in 1989. If you translate the 3 times (the current time and the 2 times to compare to) in epoch time you can just use > < = etc.

For information on getting epoch time, Try here (has many languages): http://shafiqissani.wordpress.com/2010/09/30/how-to-get-the-current-epoch-time-unix-timestamp/

Unfortunately, my java is lacking or I'd give you some code :)

Edit: Java epoch time code:

long epoch = System.currentTimeMillis()/1000;

Because my Java is bad and I don't have an interpreter where I am, I can only suggest using this site to help convert the other dates to epoch time: http://www.epochconverter.com/

score 1 · Answer 4 · answered Sep 12 '13 at 13:47

1

There is before(Date) and after(Date) method in Date Class.

secondDate.before(firstDate)

answered Sep 12 '13 at 13:47

JNL

4,683
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score 0 · Answer 5 · answered Sep 12 '13 at 13:47

0

If you use Calendar class, it has explicit before() and after() methods:

Calendar startDate = ...
Calendar endData = ...
isBetween = currentDate.after(startDate) && currentDate.before(endDate);

answered Sep 12 '13 at 13:47

dah4ns

31
2

How do I figure out whether the current time is in between two times?

5 Answers5