Get specific 15 minute time frames based on current time

Question

I would like to get a 15 minute timeframe based on the current time.

For instance:

Time interval for every 15 minutes.

ie 12 to 1 is divided into four timeframes [ 12:00 to 12:15, 12:16 to 12:30, 1:31 to 12:45, 12:46 to 1:00]

If the current time 12:34means, I need to return the timeframe as12:31 to 12:45

Is this something we can do easily with the Java 8 date and time API?

Answer 1

You can create TemporalAdjusterone that calculates the end of the current 15 minute period and calculates the beginning of the period by removing 14 minutes.

It might look like this:

public static void main(String[] args) {
  LocalTime t = LocalTime.of(12, 34);
  LocalTime next15 = t.with(next15Minute());
  System.out.println(next15.minusMinutes(14) + " - " + next15);
}

public static TemporalAdjuster next15Minute() {
  return (temporal) -> {
    int minute = temporal.get(ChronoField.MINUTE_OF_DAY);
    int next15 = (minute / 15 + 1) * 15;
    return temporal.with(ChronoField.NANO_OF_DAY, 0).plus(next15, ChronoUnit.MINUTES);
  };
}

which outputs 12:31 - 12-45.

. , DST - .

Answer 2

API Date . (15 ) . 15- . , . . :

import java.util.*;
import java.lang.*;
import java.io.*;

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        long ms = new Date().getTime();
        System.out.println("Current time: " + new Date().toString());

        long fifteen = 15 * 60 * 1000;
        long newMs = (ms / fifteen) * fifteen + fifteen;
        System.out.println("Calculated time: " + new Date(newMs));
    }
}

.

:

LocalDate

import java.util.*;
import java.lang.*;
import java.io.*;
import java.time.*;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        LocalTime now = LocalTime.now();
        System.out.println(now);

        LocalTime next = now.with((temp) -> {
            int currentMinute = temp.get(ChronoField.MINUTE_OF_DAY);
            int interval = (currentMinute / 15) * 15 + 15;
            temp = temp.with(ChronoField.SECOND_OF_MINUTE, 0);
            temp = temp.with(ChronoField.MILLI_OF_SECOND, 0);
            return temp.with(ChronoField.MINUTE_OF_DAY, interval);  
        });
        System.out.println(next);
    }
}