What is BusinessHours Class in Salesforce Apex? And how we can use them?

Hi,

Example to use BusinessHours class -

 public class BusinessDays {

 private List<Boolean> businessDay = new Boolean[7];
 private List<Time> startHours = new Time [7];
 private List<Time> endHours = new Time [7];
 private Date knownSunday = date.newInstance(2013, 1, 6);

 // Constructor creates businessDay array
 public BusinessDays() {

 BusinessHours bh =
 [Select
 SundayStartTime, MondayStartTime, TuesdayStartTime,
WednesdayStartTime, ThursdayStartTime, FridayStartTime,
 SaturdayStartTime, SundayEndTime, MondayEndTime,TuesdayEndTime,
 WednesdayEndTime, ThursdayEndTime, FridayEndTime,SaturdayEndTime
 From BusinessHours 
 Where IsDefault=true];

 businessDay[0] = (bh.SundayStartTime != null);
 businessDay[1] = (bh.MondayStartTime != null);
 businessDay[2] = (bh.TuesdayStartTime != null);
 businessDay[3] = (bh.WednesdayStartTime != null);
 businessDay[4] = (bh.ThursdayStartTime != null);
 businessDay[5] = (bh.FridayStartTime != null);
 businessDay[6] = (bh.SaturdayStartTime != null);
 
 startHours[0] = bh.SundayStartTime;
 startHours[1] = bh.MondayStartTime;
 startHours[2] = bh.TuesdayStartTime;
 startHours[3] = bh.WednesdayStartTime;
 startHours[4] = bh.ThursdayStartTime;
 startHours[5] = bh.FridayStartTime;
 startHours[6] = bh.SaturdayStartTime;

 endHours[0] = bh.SundayEndTime;
 endHours[1] = bh.MondayEndTime;
 endHours[2] = bh.TuesdayEndTime;
 endHours[3] = bh.WednesdayEndTime;
 endHours[4] = bh.ThursdayEndTime;
 endHours[5] = bh.FridayEndTime;
 endHours[6] = bh.SaturdayEndTime;

 }

 // Check if today is a business day
 public Boolean isBusinessDay(Date inputDate) {
 // index i is index into the businessDay array based on inputDate
 Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(inputDate)),7);
 return (businessDay[i]);
 }
 
 // Get the start time
 public Time getStartTime(Date inputDate) {
 Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(inputDate.date)),7);
 return (startHours[i]);
 }

 // Gets next business day, skipping non business days
 public Date nextBusinessDay(Datetime inputDatetime) {
 Integer i =
 Math.mod(Math.abs(this.knownSunday.daysBetween(inputDatetime.date())),7);
 Datetime returnDate = inputDatetime;
 while (!businessDay[Math.mod(i, 7)]) {
 i++;
 returnDate = returnDate.addDays(1);
 }
 return returnDate.date;
 }

 }

Hope it helps.