Objective-C : (private / public properties) making a property readonly for outside class calls and readwrite for self calls

Question

Would you know a way to make a property readonly for outside calls and readwrite for inside calls ?

I\'ve read times ago somthing that seemed like

In the .h

Answer 1

This issue is largely eliminated if you're moving to ARC. Instead of two property declarations, you'd declare it once in the header.

@property(nonatomic, readonly) NSDate* theDate;

And then in the class extension, simply declare a __strong instance variable.

@interface TheClassName()
{
    __strong NSDate* _theDate;
}
@end

And synthesize them appropriately in the implementation

@implementation TheClassName
@synthesize theDate = _theDate;

Now you can set the instance variable.

_theDate = [NSDate date];

And ARC will magically inline the appropriate retain/release functionality into your code to treat it as a strong/retained variable. This has the advantage of being faster than the old style (retain) properties as well as ARC inlines the retain/release code at compile time.

Answer 2

In the .m, you shouldn't put @property again. I'm not sure what effect that has, though. Did you mean to use @synthesize?

Note that theDate will be read/write inside the class implementation anyway, regardless of being readonly to the outside world.

Answer 3

In your .h:

@property(nonatomic, retain, readonly) NSDate* theDate;

In your .m:

@interface TheClassName()
@property(nonatomic, retain, readwrite) NSDate* theDate;
@end

Answer 4

If the property is backed by a variable, the variable is read-write from inside the class be default. Make the property read-only, and your design goal will be met. Inside the class, refer to the variable without prepending self..