ios - Set Default values of NSString properties automatically -

i have many bean/data classes in code i'm using convert json network communication purposes. issue is, if there's nsstring property in class want set default value empty string @"" rather nil. 1 option have :setting default values nsstring properties have write code set properties values, don't want this.

i tried getting properties using objc runtime , did this:

    unsigned int numberofproperties = 0;     objc_property_t *propertyarray = class_copypropertylist([self class], &numberofproperties);      (nsuinteger = 0; < numberofproperties; i++)     {         objc_property_t property = propertyarray[i];         nsstring *name = [nsstring stringwithutf8string:property_getname(property)];         const char * propattr = property_getattributes(property);         nsstring *propstring = [nsstring stringwithutf8string:propattr];         nsarray *attrarray = [propstring componentsseparatedbystring:@"\""];         if (attrarray.count > 0) {             nsstring *proptype = [attrarray objectatindex:1];             if ([proptype containsstring:@"nsstring"]) {                 [self setvalue:@"" forkey:name];             }         }      }     free(propertyarray); 

this working charm me. issue have inherited classes , code sets values child class, doesn't sets values of properties in base class. i'm using xcode 6.3.1 & ios 8.x. appreciated. thanks

you may define recursive method setdefaultpropvaluesforclass: in bean/data base class, e.g. bean, , invoke base class init method. see implementation below:

@interface bean : nsobject // add props // ... // ..... @end  @implementation bean  - (instancetype)init {     self = [super init];     if (self) {         [self setdefaultpropvalues];         // todo: other initializations     }     return self; }  - (void)setdefaultpropvalues {     [self setdefaultpropvaluesforclass:self.class]; }  - (void)setdefaultpropvaluesforclass:(class)refclass {     if (![refclass issubclassofclass:[bean class]]) {         return;     }     // first set default property values in super classes     class baseclass = class_getsuperclass(refclass);     [self setdefaultpropvaluesforclass:baseclass];     //     unsigned int numberofproperties = 0;     objc_property_t *propertyarray = class_copypropertylist(refclass, &numberofproperties);     (nsuinteger = 0; < numberofproperties; i++)     {         objc_property_t property = propertyarray[i];         nsstring *name = [nsstring stringwithutf8string:property_getname(property)];         const char * propattr = property_getattributes(property);         nsstring *propstring = [nsstring stringwithutf8string:propattr];         nsarray *allattrs = [propstring componentsseparatedbystring:@","];         // check if property readonly         if (nsnotfound == [allattrs indexofobject:@"r"]) {             // find property type token             nsarray * attrarray = [propstring componentsseparatedbystring:@"\""];             if (attrarray.count > 1) {                 class proptype = nsclassfromstring([attrarray objectatindex:1]);                 if ([proptype issubclassofclass:[nsstring class]]) {                     [self setvalue:@"" forkey:name];                 }             }         }     }     free(propertyarray); }  @end