Mutable @dynamic properties

[Brendan Duddridge]

Hi,

I have a property on my class called "values". It's an NSMutableDictionary.

However, I guess the JSON parser doesn't like that it's mutable. Is there a way to tell CBL on iOS that I want my values property to be mutable?

I get the following error otherwise:

WARNING: Dynamic property TFFormEntry.values has type '@"NSMutableDictionary"' unsupported by TFFormEntry

Thanks,

Brendan 

[Jens Alfke]

On Jul 17, 2015, at 1:17 PM, Brendan Duddridge <bren...@gmail.com> wrote:

I have a property on my class called "values". It's an NSMutableDictionary.

However, I guess the JSON parser doesn't like that it's mutable. Is there a way to tell CBL on iOS that I want my values property to be mutable?

CBLModel doesn’t support mutable types. The problem is detecting changes — if you modify the contents of the dictionary, the dictionary property itself isn’t changed, so the model object doesn’t know it needs to save back to the database. (I believe Core Data’s NSManagedObject has the same limitation.)

In general, mutable property objects are considered a bad idea by many people, because the owning object loses control over the property value, which can be mutated at any moment. (There’s been discussion of this on cocoa-dev recently.)

—Jens

[Brendan Duddridge]

So to work around it, I'm creating a mutable copy of the values dictionary, then setting my individual properties in the values dictionary, then setting the entire dictionary back using self.values = [NSDictionary dictionaryWithDictionary:mutableDict];

Does that seem reasonable?

I'd love to read the discussion on cocoa-dev if you have a link to that.

Thanks!

Brendan

[Jens Alfke]

On Jul 17, 2015, at 4:15 PM, Brendan Duddridge <bren...@gmail.com> wrote:

So to work around it, I'm creating a mutable copy of the values dictionary, then setting my individual properties in the values dictionary, then setting the entire dictionary back using self.values = [NSDictionary dictionaryWithDictionary:mutableDict];

That’s fine, although self.values = [mutableDict copy] is shorter.

—Jens