ios - Pattern for determining if object is fully or partially loaded -

the question not strictly tied ios, since encountered in ios app speak in terms of objective-c.

my ios app client, gets data server. data server json, , mapped classes. problem appears when server send necessary part of object.

lets full object is

{ "a" : 1, "b" : 2, "c" : 3 } 

my class mapped is

@class myobject {     int a, b, c; }  @property (nonatomic) int a, b, c;  -(id) initfromdictionary:(nsdictionary*)dict  @end  @implementation myobject  -(id) initfromdictionary:(nsdictionary*)dict {     self = [super init];     if (self)     {         = [dict[@"a"] intvalue];         b = [dict[@"b"] intvalue];         c = [dict[@"c"] intvalue];     }     return self; }  @end 

the server can send

{ "a" : 1, "c" : 3 } 

for request getaandc ,

{ "a" : 1, "b" : 2 } 

for - getaandb (these requests not dependent, thing similar object use). not need information b in first 1 , c in second one.

the problem following. when write code these requests surely know fields returned , not use empty field, after time may forget request returned partial object or full, , try use empty field. there can lot of errors, hard find.

is there practices case or maybe pattern determining if object or partially loaded , warning developer it?

you can implement :

@implementation myobject

-(id) initfromdictionary:(nsdictionary*)dict {     self = [super init];     if (self)     {           = ([dict objectforkey: @"a"]) ? [[dict objectforkey: @"a"] intvalue] : 0;          b = ([dict objectforkey: @"b"]) ? [[dict objectforkey: @"b"] intvalue] : 0;          c = ([dict objectforkey: @"c"]) ? [[dict objectforkey: @"c"] intvalue] : 0; 

// here can replace 0 nil in case if variable , b , c object type i.e. (id) type or can use default value here per convenience can track if partially or loaded

        if ((a == 0) || (b == 0) || (c == 0))          {                 nslog(@"object partially loaded values : %d , b : %d , c : %d", a,b,c);         }else{           nslog(@"object loaded values : %d , b : %d , c : %d", a,b,c);         }          }      return self;  }     @end 

or

@implementation myobject  -(id) initfromdictionary:(nsdictionary*)dict {     self = [super init];     if (self)     {         nsarray *keys = [dict allkeys];         for(nsstring * key in keys)         {          [self setvaluetoitsvariableforkey:key fromdictionary: dict];          }     }     return self; }  - (void)setvaluetoitsvariableforkey:(nsstring *)key fromdictionary: (nsdictionary *)dict  {      switch ([key intvalue])     {        case :            = [[dict objectforkey: key] intvalue];           break;        case : b            b = [[dict objectforkey: key] intvalue];           break;          case : c            c = [[dict objectforkey: key] intvalue];           break;     }    }    @end