sortbydifferentdateproperties.m

#import <Foundation/Foundation.h>



@interface Birthday : NSObject
@property (nonatomic, strong) NSDate *birthday;
@property (nonatomic, copy) NSString *name;
-(id)initWithName:(NSString *) name birthdayDate:(NSDate *) date;
@end

@implementation Birthday
-(id)initWithName:(NSString *) name birthdayDate:(NSDate *) date
{
    if(self = [super init]){
        _birthday = date;
        _name = name;
    };
    
    return self;
}

-(NSString *)description
{
    return [NSString stringWithFormat:@"Birthday:\t %@: %@", _birthday, _name];
}
@end




@interface Event : NSObject
@property (nonatomic, strong) NSDate *day;
@property (nonatomic, copy) NSString *title;
-(id)initWithTitle:(NSString *) title date:(NSDate *) date;
@end

@implementation Event
-(id)initWithTitle:(NSString *) title date:(NSDate *) date;
{
    if(self = [super init]){
        _day  = date;
        _title = title;
    };
    
    return self;
}

-(NSString *)description
{
    return [NSString stringWithFormat:@"Event:\t\t %@: %@", _day, _title];
}
@end




@interface OtherEvent : NSObject
@property (nonatomic, strong) NSDate *date;
@property (nonatomic, copy) NSString *title;
-(id)initWithTitle:(NSString *) title date:(NSDate *) date;
@end

@implementation OtherEvent
-(id)initWithTitle:(NSString *) title date:(NSDate *) date;
{
    if(self = [super init]){
        _date  = date;
        _title = title;
    };
    
    return self;
}

-(NSString *)description
{
    return [NSString stringWithFormat:@"OtherEvent: %@: %@", _date, _title];
}
@end



int main(int argc, const char * argv[])
{

    @autoreleasepool {
        
        NSMutableArray *array = [@[] mutableCopy];
        [array addObject:[[Birthday alloc] initWithName:@"Bibo"
                                           birthdayDate:(
                                                         {
                                                             NSDateComponents *comps = [[NSDateComponents alloc] init];
                                                             comps.year = 1969;
                                                             comps.month = 7;
                                                             comps.day = 15;
                                                             [[NSCalendar currentCalendar] dateFromComponents:comps];
                                                         })
                          ]];
        
        [array addObject:[[Birthday alloc] initWithName:@"Jimi Hendrix"
                                           birthdayDate:(
                                                         {
                                                             NSDateComponents *comps = [[NSDateComponents alloc] init];
                                                             comps.year = 1942;
                                                             comps.month = 11;
                                                             comps.day = 27;
                                                             [[NSCalendar currentCalendar] dateFromComponents:comps];
                                                         })
                          ]];
        
        [array addObject:[[Event alloc] initWithTitle:@"Vacation end"
                                                 date:(
                                                       {
                                                           NSDateComponents *comps = [[NSDateComponents alloc] init];
                                                           comps.year = 2014;
                                                           comps.month = 6;
                                                           comps.day = 21;
                                                           [[NSCalendar currentCalendar] dateFromComponents:comps];
                                                       })
                          
                          ]];
        
        [array addObject:[[Birthday alloc] initWithName:@"Samson"
                                           birthdayDate:(
                                                         {
                                                             NSDateComponents *comps = [[NSDateComponents alloc] init];
                                                             comps.year = 1977;
                                                             comps.month = 9;
                                                             comps.day = 3;
                                                             [[NSCalendar currentCalendar] dateFromComponents:comps];
                                                         })
                          
                          ]];
        
        [array addObject:[[Event alloc] initWithTitle:@"Vacation begin"
                                                 date:(
                                                       {
                                                           NSDateComponents *comps = [[NSDateComponents alloc] init];
                                                           comps.year = 2014;
                                                           comps.month = 6;
                                                           comps.day = 1;
                                                           [[NSCalendar currentCalendar] dateFromComponents:comps];
                                                       })
                          
                          ]];
        
        [array addObject:[[OtherEvent alloc] initWithTitle:@"Woodstock Music and Art Festival"
                                                      date:(
                                                            {
                                                                NSDateComponents *comps = [[NSDateComponents alloc] init];
                                                                comps.year = 1969;
                                                                comps.month = 15;
                                                                comps.day = 8;
                                                                [[NSCalendar currentCalendar] dateFromComponents:comps];
                                                            })
                          ]];
        
        
        
        NSDictionary *dateMapper = @{NSStringFromClass([Birthday class]): @"birthday",
                                     NSStringFromClass([Event class]): @"day",
                                     NSStringFromClass([OtherEvent class]): @"date"};
        
        [array sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
            NSDate *date1 = [obj1 valueForKey: dateMapper[NSStringFromClass([obj1 class])]];
            NSDate *date2 = [obj2 valueForKey: dateMapper[NSStringFromClass([obj2 class])]];
            
            return [date1 compare:date2];
        }];
    
        for (id obj in array) {
            NSLog(@"%@", obj);
        }
        
    }
    return 0;
}