How would I add only business days to an NSDate?

Question

I have an issue related to calculating business days in Objective-C.

I need to add X business days to a given NSDate.

For example, if

Answer 1

I took @steve's answer and added a method to calculate the days of all the federal holidays in USA and put it all in a Category. I've tested it and it works nicely. Check it out.

#import "NSDate+BussinessDay.h"

@implementation NSDate (BussinessDay)

-(NSDate *)addBusinessDays:(int)daysToAdvance{
    NSDate * end = self;
    NSArray *holidays = [self getUSHolidyas];
    for (int i = 0; i < daysToAdvance; i++)
    {
        // Move the date forward by one day:
        end = [self addDays:1 toDate:end];

        // If the current date is a weekday, advance:
        end = [self ensureDateIsWeekday:end];

        // If the current date is a holiday, advance:
        end = [self ensureDateIsntHoliday:end forHolidays:holidays];
    }

    return end;
}

#pragma mark - Bussiness Days Calculations

-(BOOL)isWeekday:(NSDate *) date{
    int day = (int)[[[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:date] weekday];

    const int kSunday = 1;
    const int kSaturday = 7;

    BOOL isWeekdayResult = day != kSunday && day != kSaturday;
    return isWeekdayResult;
}

-(NSDate *)addDays:(int)days toDate:(NSDate *)date{
    NSDateComponents * components = [[NSDateComponents alloc] init];
    [components setDay:days];

    NSDate * result = [[NSCalendar currentCalendar] dateByAddingComponents:components toDate:date options:0];
    return result;
}

-(NSDate *)ensureDateIsWeekday:(NSDate *)date{
    while (![self isWeekday:date])
    {
        // Add one day to the date:
        date = [self addDays:1 toDate:date];
    }

    return date;
}

-(BOOL)isHoliday:(NSDate *)date forHolidays:(NSArray *)holidays{
    BOOL isHolidayResult = NO;

    const unsigned kUnits = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit;
    NSDateComponents * components = [[NSCalendar currentCalendar] components:kUnits fromDate:date];

    for (int i = 0; i < [holidays count]; i++)
    {
        NSDate * holiday = [holidays objectAtIndex:i];
        NSDateComponents * holidayDateComponents = [[NSCalendar currentCalendar] components:kUnits fromDate:holiday];

        if ([components year] == [holidayDateComponents year]
            && [components month] == [holidayDateComponents month]
            && [components day] == [holidayDateComponents day])
        {
            isHolidayResult = YES;
            break;
        }
    }

    return isHolidayResult;
}

-(NSDate *)ensureDateIsntHoliday:(NSDate *)date forHolidays:(NSArray *)holidays{
    while ([self isHoliday:date forHolidays:holidays])
    {
        // Add one day to the date:
        date = [self addDays:1 toDate:date];
    }

    return date;
}

-(NSArray *)getUSHolidyas{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    formatter.dateFormat = @"yyyy";

    NSString *year = [formatter stringFromDate:[NSDate date]];
    NSString *nextYear = [formatter stringFromDate:[NSDate dateWithTimeIntervalSinceNow:(60*60*24*365)]];
    formatter.dateFormat = @"M/d/yyyy";

    //Constant Holidays
    NSDate *newYearsDay = [formatter dateFromString:[NSString stringWithFormat:@"1/1/%@",nextYear]]; //Use next year for the case where we are adding days near end of december.
    NSDate *indDay = [formatter dateFromString:[NSString stringWithFormat:@"7/4/%@",year]];
    NSDate *vetDay = [formatter dateFromString:[NSString stringWithFormat:@"11/11/%@",year]];
    NSDate *xmasDay = [formatter dateFromString:[NSString stringWithFormat:@"12/25/%@",year]];


    //Variable Holidays
    NSInteger currentYearInt = [[[NSCalendar currentCalendar]
                                 components:NSYearCalendarUnit fromDate:[NSDate date]] year];

    NSDate *mlkDay = [self getTheNth:3 occurrenceOfDay:2 inMonth:1 forYear:currentYearInt];
    NSDate *presDay = [self getTheNth:3 occurrenceOfDay:2 inMonth:2 forYear:currentYearInt];
    NSDate *memDay = [self getTheNth:5 occurrenceOfDay:2 inMonth:5 forYear:currentYearInt]; // Let's see if there are 5 Mondays in May
    NSInteger month = [[[NSCalendar currentCalendar] components:NSYearCalendarUnit fromDate:memDay] month];
    if (month > 5) { //Check that we are still in May
        memDay = [self getTheNth:4 occurrenceOfDay:2 inMonth:5 forYear:currentYearInt];
    }
    NSDate *labDay = [self getTheNth:1 occurrenceOfDay:2 inMonth:9 forYear:currentYearInt];
    NSDate *colDay = [self getTheNth:2 occurrenceOfDay:2 inMonth:10 forYear:currentYearInt];
    NSDate *thanksDay = [self getTheNth:4 occurrenceOfDay:5 inMonth:11 forYear:currentYearInt];

    return @[newYearsDay,mlkDay,presDay,memDay,indDay,labDay,colDay,vetDay,thanksDay,xmasDay];
}

-(NSDate *)getTheNth:(NSInteger)n occurrenceOfDay:(NSInteger)day inMonth:(NSInteger)month forYear:(NSInteger)year{

    NSDateComponents *dateComponents = [[NSDateComponents alloc] init];

    dateComponents.year = year;
    dateComponents.month = month;
    dateComponents.weekday = day; // sunday is 1, monday is 2, ...
    dateComponents.weekdayOrdinal = n; // this means, the first of whatever weekday you specified
    return [[NSCalendar currentCalendar] dateFromComponents:dateComponents];
}

@end