CODEWITHSUNDEEP
javadatetime
xyz777
xyz777

Reputation: 67

Calculate timetable / Remaining time (Java)

I am trying to calculate remaining time for bus timetable. So I stored all list of tables in ArrayList, and I want to calculate the remaining time only just for one timetable at a time. For example, assume the list has 8:00 and 8:15, and the current time is 7:55. What I want is that calculate the remaining time with 8:00 not 8:15, and also if the current time is 8:01, the calculation should be happening with 8:15 not 8:00. If you guys help me with that (any links or sample methods), that would be fantastic.

Upvotes: 0

Views: 513

Answers (2)

MadProgrammer
MadProgrammer

Reputation: 347244

A lot comes down to how you are storing your time information, for example, if you are using something like Date or LocalTime, you can simply sort the List of times and use Collections.binarySearch to find a suitable time...

List<LocalTime> times = new ArrayList<>(25);
times.add(LocalTime.of(9, 0));
times.add(LocalTime.of(8, 45));
times.add(LocalTime.of(8, 30));
times.add(LocalTime.of(8, 15));
times.add(LocalTime.of(8, 0));
times.add(LocalTime.of(7, 45));
times.add(LocalTime.of(7, 30));
times.add(LocalTime.of(7, 15));
times.add(LocalTime.of(7, 0));

int result = Collections.binarySearch(times, LocalTime.of(7, 55), new Comparator<LocalTime>() {
    @Override
    public int compare(LocalTime o1, LocalTime o2) {

        LocalTime startRange = o1.minusMinutes(15);
        LocalTime endRange = o1;

        if ((o2.equals(o1) || startRange.isBefore(o2)) && (o2.equals(o1) || o2.isBefore(o1))) {
            return 0;
        } 
        return o1.compareTo(o2);
    }
});

if (result >= 0) {
    System.out.println(times.get(result));
}

Which outputs 08:00

Now,

if ((o2.equals(o1) || startRange.isBefore(o2)) && (o2.equals(o1) || o2.isBefore(o1))) {

Is matching an exact period (7:45-8:00 inclusive, for example), this might not be what you want (so it's 8:00, you've probably missed the bus ;)) so you might be able to use something like

if (startRange.isBefore(o2) && o2.isBefore(o1)) {

which will match 7:46-7:59 inclusive, for example or combinations based on your needs...

Upvotes: 1

Bartlomiej Lewandowski
Bartlomiej Lewandowski

Reputation: 11180

Assuming the list is sorted, you can loop through the list and return the first element which the difference is positive.

Pseudocode:

for each time in timetable:
    difference = time - current_time
    if difference > 0: return difference

Upvotes: 0

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