How do I call +class methods in Objective C without referencing the class?
- by TimM
I have a series of "policy" objects which I thought would be convenient to implement as class methods on a set of policy classes. I have specified a protocol for this, and created classes to conform to (just one shown below)
@protocol Counter
+(NSInteger) countFor: (Model *)model;
@end
@interface CurrentListCounter : NSObject <Counter>
+(NSInteger) countFor: (Model *)model;
@end
I then have an array of the classes that conform to this protocol (like CurrentListCounter does)
+(NSArray *) availableCounters {
return [[[NSArray alloc] initWithObjects: [CurrentListCounter class],[AllListsCounter class], nil] autorelease];
}
Notice how I am using the classes like objects (and this might be my problem - in Smalltalk classes are objects like everything else - I'm not sure if they are in Objective-C?)
My exact problem is when I want to call the method when I take one of the policy objects out of the array:
id<Counter> counter = [[MyModel availableCounters] objectAtIndex: self.index];
return [counter countFor: self];
I get a warning on the return statement - it says -countFor: not found in protocol (so its assuming its an instance method where I want to call a class method). However as the objects in my array are instances of class, they are now like instance methods (or conceptually they should be).
Is there a magic way to call class methods? Or is this just a bad idea and I should just create instances of my policy objects (and not use class methods)?
