Is there an easier way to get start of current day time than this?

Question

I basically want to get zero or beginning hour for currrent day.

def today = Calendar.instance
today.set(Calendar.HOUR_OF_DAY, 0)
today.set(Calendar.MINUTE, 0)
today.set(Calendar.SECOND, 0)
println today // Mon Mar 15 00:00:00 SGT 2010

Answer 1

According to Groovy date documentation, it seems that it's the optimal way.

However, using Groovy with keyword, you can compress a little your statements

def today = Calendar.instance
with(today) {
    set Calendar.HOUR_OF_DAY, 0
    set Calendar.MINUTE, 0
    set Calendar.SECOND, 0
}
println today // Mon Mar 15 00:00:00 SGT 2010

Answer 2

You could use the clearTime() function of Calendar in Groovy:

def calendar = Calendar.instance
calendar.with {
  clearTime()
  println time
}

It'd be nice to have a convenience method that clears the time portion of a java.util.Date and/or java.util.Calendar.
There are numerous use cases where it makes sense to compare month/day/year only portions of a calendar or date. Essentially, it would perform the following on Calendar:

void clearTime() {
    clear(Calendar.HOUR_OF_DAY)
    clear(Calendar.HOUR)
    clear(Calendar.MINUTE)
    clear(Calendar.SECOND)
    clear(Calendar.MILLISECOND) 
 }

Answer 3

Not simpler than the other solutions, but less lines:

def now = new GregorianCalendar()
def today = new GregorianCalendar(now.get(Calendar.YEAR), now.get(Calendar.MONTH), now.get(Calendar.DAY_OF_MONTH))
println today.getTime()