Question

I am trying to build a map with time starting from 06.00 to 23:59 as keys and I will keep track of a number for each time as value.I need the time to stored HH.mm as format and I am planning to build the map using a loop by incrementing one minute and run the following code inside the loop.The problem here is since I have to set the format as HH.MM strictly I have to get the input as String and format it and then parse it back as double which affects the perfomance.Is there a global setting to change so that whatever double number I choose in this particular class should be of the format ##.##.Also point here to note is since it is time it ends at 60 minutes and hence I have to break the current iteration with the help of .6.

    Map map = new LinkedHashMap();
    //Edit:Moved DecimalFormat Outside the loop
    DecimalFormat df = new DecimalFormat("##.##");
    for (double time= 06.00; time<= 22.00; time= time+ 01.00)
    {

        String timeString = df.format(appointmentTime);
        time = Double.parseDouble(timeString);

        if (timeString.indexOf(".6") != -1)
        {
            time= time+ 00.40;

        }
        map.put(time,"<number>");
    }

Answer 1

I beliI believe you choose the most complicated approach. Instead of iterating the time variable you could iterate a simple number indicating the minutes since 0 o’clock and then generate your time double only for the map.

for(int totalMinutes = 6 * 60; totalMinutes <= 22 * 60; totalMinutes ++) {
    map.put(buildTimeDouble(totalMinutes),”<number>”);
}

But I believe (I do not understand your question in that point), it would be better not to use a double for the map key, instead you could use your own Time class, something like:

Time{
  private  int hour;
  private int minutes;

  public Time(int hour; int minutes) {
     this.hour = hour;
      this.minutes = minutes;
   }

   public toString(){
      return hour + “:” + minutes
   }

   public static Time fromTotalMinutes(int totalMinutesSinceZeroOclock){
      return new Time(totalMinutesSinceZeroOclock / 60; totalMinutesSinceZeroOclock / 60);
   }
}