iphone - is this a bad Core Data pattern for sharing functionality? -

i have app , there basic functionality needs shared across several controllers, 1 being adding , removing call bookmarkedobjects data store. created following funciton , seems working , apply pattern other function in code adding objects order, seeing if order exist ect..

here doing:

+(void) removebookmark: (nsstring *) aitemid  withcustomernumber: (nsstring *) acustomernumber withmanufacturerid: (nsstring *) amanufacturerid withmanagedobjectcontext: (nsmanagedobjectcontext *) acontext {     nsfetchrequest *request = [[nsfetchrequest alloc] init];     [request setentity:[nsentitydescription entityforname:@"bookmarkeditem" inmanagedobjectcontext:acontext]];     [request setpredicate:[nspredicate predicatewithformat:@"customernumber==%@ , manufacturerid==%@ , itemid==%@", acustomernumber, amanufacturerid, aitemid]];     [request setfetchlimit:1];     nserror *error = nil;     nsarray *results = [acontext executefetchrequest:request    error:&error];     [request release], request = nil;     [acontext deleteobject:[results lastobject]];     [acontext save:&error]; } 

i suggest make singleton class , add such type of function in it.the main benefit of class methods loaded on compile time if there 5 such functions app take unnecessary memory, i'll suggest define class named sharedfunctions

in .h

@interface sharedfunctions : nsobject { } +(sharedfunctions*)sharedinstance; -(void)yourfunction; ..... //make many instace methods want @end 

in .m

@implementation sharedfunctions static sharedfunctions* singletoninstance = nil;  -(id)init {     if (self = [super init])     {      }     return self; }   +(sharedfunctions*)sharedinstance {     @synchronized(self) {         if (singletoninstance == nil)          {         singletoninstance =  [[sharedfunctions alloc] init];          }     }     return singletoninstance; }  ///and define methods  -(void)yourfunction {        //somthing } @end 

now use methods call

 [[sharedfunctions sharedinstance] yourfunction]; 

by way such methods @ 1 place , there 1 class method no memory issue.