Round Off time to the upcoming nearest 15 minutes time using Groovy

Question

I am trying to round off time to the upcoming 15 minutes time. e.g :

1. 2017-12-11T13:11:51.728Z to 2017-12-11T13:15:00.000Z
2. 2017-12-11T13:21:51.728Z to 2017-12-11T13:30:00.000Z

Groovy code :

def currentTime = context.expand('${#Project#currentTime}')
log.info currentTime
date1 =  new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'").parse(currentTime)
//Round off the time nearest to the mod 15
Calendar calendar = Calendar.getInstance();
calendar.setTime(date1);
int unroundedMinutes = calendar.get(Calendar.MINUTE);
int mod = unroundedMinutes % 15;
log.info calendar.add(Calendar.MINUTE, mod < 8 ? -mod : (15-mod));

Output :

Mon Dec 11 14:32:32 IST 2017:INFO:2017-12-11T14:32:32.690Z
Mon Dec 11 14:32:32 IST 2017:INFO:null

Answer 1

Here you go:

• In order to get the difference minutes, created a closure.
• The closure gets called recursively if needed.
• If the current minutes is divisible by 15, it won't adjust the time; that is the reason for adding third value in the list.
• To be able to test with multiple values, used list of dates. You may use it for single value as well.

def timez = ['2017-12-11T13:11:51.728Z', '2017-12-11T13:21:51.728Z', '2017-12-11T13:30:00.000Z']
def dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
def roundValue = 15
//Change timezone if needed
def tz = 'IST'

TimeZone.setDefault(TimeZone.getTimeZone(tz))

Calendar calendar = Calendar.getInstance()

def getNearestMinutes
//Closure which gets called recursive
getNearestMinutes = { cmin, nearMin = roundValue ->
    def tempResult = cmin % nearMin
    if ( tempResult < nearMin && (0 < (nearMin - cmin)) ) {
        return (nearMin - cmin)
    } else { 
        return getNearestMinutes(cmin, nearMin+roundValue) 
    }
}


//Loop thru times and round the time
timez.each {
    calendar.time = Date.parse(dateFormat,it)
    def currentMinute = calendar.get(Calendar.MINUTE)
    def cof = currentMinute % roundValue
    if (cof) {
        currentMinute += getNearestMinutes(currentMinute)
        calendar.set(Calendar.MINUTE, currentMinute )
    }       
    calendar.set(Calendar.SECOND, 0)
    calendar.set(Calendar.MILLISECOND, 0)
    log.info calendar.time.format(dateFormat)   

}

You can quickly try it online demo

EDIT: Felt that the solution could be made something more simple than applying above difficult conditions.

Here is another solution to round time to near future 15 min. Yet, easy to read code unlike multiple conditions in the first solution. This is simple one using Switch statement

def timez = ['2017-12-11T13:11:51.728Z', '2017-12-11T13:21:51.728Z', '2017-12-11T13:30:00.000Z', '2017-12-11T13:46:00.000Z']
def dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
def roundValue = 15
//Change timezone if needed
def tz = 'IST'

TimeZone.setDefault(TimeZone.getTimeZone(tz))

Calendar calendar = Calendar.getInstance()

def getNexTime = { min ->
  def result
  switch(min) {
    case 1..15: 
        result = 15
        break
    case 16..30:
        result = 30
        break
    case 31..45:
        result = 45
        break
    case 46..60:
        result = 60
        break
    default:
        result = 0
        break
  }
  result
}



//Loop thru times and round the time
timez.each {
    calendar.time = Date.parse(dateFormat,it)
    def currentMinute = calendar.get(Calendar.MINUTE)
    if (0 != getNexTime(currentMinute)) {
        calendar.set(Calendar.MINUTE, getNexTime(currentMinute) )
    }
    calendar.set(Calendar.SECOND, 0)
    calendar.set(Calendar.MILLISECOND, 0)
    println calendar.time.format(dateFormat)    
}