Business Day Calculation in Apex Salesforce

        Here is the utility method to calculate various business day calculation such as getting next business days, business hours, validating date is business day or not, total business days between two dates, etc.

1. public class BusinessDays {
3. private List<Boolean> businessDay = new Boolean[7];
4. private List<Time> startHours = new Time [7];
5. private List<Time> endHours = new Time [7];
6. private Date knownSunday = date.newInstance(2013, 1, 6);
7. private String businessHourId;
8. private Boolean considerHolidays = false;
9.    
10.   // Constructor creates businessDay array
11.    public BusinessDays(String businessHourName, Boolean considerHolidays) {
12.      
13.      BusinessHours bh;
14.      
15.      this.considerHolidays = considerHolidays;
16.      
17.      if(businessHourName == null) {
18.          bh = [SELECT SundayStartTime, MondayStartTime, TuesdayStartTime,WednesdayStartTime, ThursdayStartTime, FridayStartTime,SaturdayStartTime, SundayEndTime, MondayEndTime,TuesdayEndTime,WednesdayEndTime, ThursdayEndTime, FridayEndTime,SaturdayEndTime
19.                             FROM BusinessHours
20.                                 WHERE IsDefault = true ];
21.      }else {
22.          bh = [SELECT SundayStartTime, MondayStartTime, TuesdayStartTime,WednesdayStartTime, ThursdayStartTime, FridayStartTime,SaturdayStartTime, SundayEndTime, MondayEndTime,TuesdayEndTime,WednesdayEndTime, ThursdayEndTime, FridayEndTime,SaturdayEndTime
23.                             FROM BusinessHours
24.                                 WHERE Name =: businessHourName ];
25.      }
26.      
27.      businessHourId = bh.Id;
28.      
29.      businessDay[0] = (bh.SundayStartTime != null);
30.      businessDay[1] = (bh.MondayStartTime != null);
31.      businessDay[2] = (bh.TuesdayStartTime != null);
32.      businessDay[3] = (bh.WednesdayStartTime != null);
33.      businessDay[4] = (bh.ThursdayStartTime != null);
34.      businessDay[5] = (bh.FridayStartTime != null);
35.      businessDay[6] = (bh.SaturdayStartTime != null);
37.      startHours[0] = bh.SundayStartTime;
38.      startHours[1] = bh.MondayStartTime;
39.      startHours[2] = bh.TuesdayStartTime;
40.      startHours[3] = bh.WednesdayStartTime;
41.      startHours[4] = bh.ThursdayStartTime;
42.      startHours[5] = bh.FridayStartTime;
43.      startHours[6] = bh.SaturdayStartTime;
45.      endHours[0] = bh.SundayEndTime;
46.      endHours[1] = bh.MondayEndTime;
47.      endHours[2] = bh.TuesdayEndTime;
48.      endHours[3] = bh.WednesdayEndTime;
49.      endHours[4] = bh.ThursdayEndTime;
50.      endHours[5] = bh.FridayEndTime;
51.      endHours[6] = bh.SaturdayEndTime;
53.    }
55.    // Check if today is a business day - Date
56.    public Boolean isBusinessDay(Date inputDate) {
57.      // index i is index into the businessDay array based on inputDate
58.      Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(inputDate)),7);
59.      Boolean isBusinessDay = businessDay[i];
60.      
61.      if(considerHolidays) {
62.          isBusinessDay = (isBusinessDay && BusinessHours.isWithin(businessHourId , datetime.newInstance(inputDate.year(), inputDate.month(),inputDate.day())));
63.      }
64.      
65.      return (isBusinessDay);
66.     }
67.    
68.     // Check if today is a business day - DateTime
69.    public Boolean isBusinessDay(DateTime inputDateTime) {
70.      
71.      Date businessDate = inputDateTime.date();
72.      Time businessTime = inputDateTime.Time();
73.      
74.      // index i is index into the businessDay array based on inputDate
75.      Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(businessDate)),7);
76.      Boolean isBusinessDay = isBusinessDay(businessDate);
77.      Boolean isBusinessHour = false;
78.      
79.      if(isBusinessDay){
80.          isBusinessHour = ( businessTime > getStartTime(businessDate) && businessTime < getEndTime(businessDate) );
81.      }
82.      
83.      return (isBusinessHour);
84.     }
86.    // Get the start time
87.    public Time getStartTime(Date inputDate) {
88.      Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(inputDate)),7);
89.      return (startHours[i]);
90.    }
91.    
92.    // Get the End time
93.    public Time getEndTime(Date inputDate) {
94.      Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(inputDate)),7);
95.      return (endHours[i]);
96.    }
98.    // Gets next business day, skipping non business days
99.    public Date nextBusinessDay(Date inputDate) {
100.      Integer i = Math.mod(Math.abs(this.knownSunday.daysBetween(inputDate)),7);
101.      Date returnDate = inputDate;
102.      
103.      do {
104.          returnDate = returnDate.addDays(1);
105.          i++;
106.      } while (!businessDay[Math.mod(i, 7)]);
107.        
108.      if(considerHolidays) {
109.          if(!BusinessHours.isWithin(businessHourId , datetime.newInstance(returnDate.year(), returnDate.month(),returnDate.day() ))) {
110.              returnDate = nextBusinessDay(returnDate);
111.          }
112.      }
113.      
114.      return returnDate;
115.    }
116.    
117.    // returns back date in numberOfDays business days
118.    public Date addBusinessDays (Date startDate, integer numberOfDays) {
119.         Date returnDate = startDate;
120.         Integer holidayCount = 0;
122.         for (integer x = 0; x < numberOfDays; x++) {
123.             returnDate = nextBusinessDay(returnDate);
124.            
125.             if(considerHolidays){
126.                 if(!BusinessHours.isWithin(businessHourId , datetime.newInstance( returnDate.year(), returnDate.month(), returnDate.day() ))){
127.                     holidayCount++;
128.                 }
129.             }
130.         }
131.        
132.         if(holidayCount > 0) {
133.             returnDate.addDays(holidayCount);  
134.         }
136.         return returnDate;
137.    }
138.    
139.    //get the total business days between two dates
140.    public Integer getTotalBusinessDays(Date inputDateStart, Date inputDateEnd) {
141.        Integer totalDays = 0;
142.        Date returnDate = inputDateStart;
143.        
144.        do {
145.            returnDate = returnDate.addDays(1);
146.            if(isBusinessDay(returnDate)) {
147.                totalDays++;
148.                
149.                if(considerHolidays){
150.                    if(!BusinessHours.isWithin(businessHourId , datetime.newInstance( returnDate.year(), returnDate.month(), returnDate.day()))) {
151.                        totalDays--;
152.                    }
153.                }
154.            }  
155.        } while (returnDate != inputDateEnd);
156.        
157.        return totalDays;
158.    }
160.  }

Thanks to my dear friend Purushothaman Annamalai, who shared this code.

Blog: Salesforce Quest

Final static variables can only be assigned in their declaration or in a static block salesforce

       You cannot assign the final static variable value other than the declaration of variable or static block. If you try to assign it, then you will get an error as "Final static variables can only be assigned in their declaration or in a static block"

To solve this issue, you need to assign like below,

1. public class StaticFinalController
2. {
3.     // assign value for get property variable using static block.
4.     public static final string staticFinalVariable{get;}
5.     static
6.     {
7.         staticFinalVariable = 'Test Value';
8.     }
9.     // Assign value on declaration
10.     public static final string staticFinalVariable1 = 'Test';
11.  
12.     public StaticFinalController()
13.     {
14.       system.debug('### Final Value is:::::'+staticFinalVariable );
15.     }
16.  
17. }

Note: Static code blocks run before the constructor.

Reference:

Static and Instance Methods, Variables, and Initialization Code