JSObservableObject

Easily add protocol-based observation to any Objective-C class

• No need to write manual observer implementations, just inherit from JSObservableObject and everything you need to for protocol-based observation will be setup for you.
• Protocol-based observation is much easier to maintain and less prone to silent failures than, for example, key value observation.
• Works with any existing observation protocols you might have.

Here's how to use JSObservableObject:

1. Declare the protocol your observers must implement

@protocol MyClassObserver <NSObject>

- (void)myObject:(MyClass *)object didPerformTaskWithObject:(id)anotherObject;

@end

2. Inherit from JSObservableObject using the JSObservableObjectInterface macro

#import "JSObservableObject.h"

JSObservableObjectInterface(MyClass, MyClassObserver)

// Your class' public API methods here

@end

This will setup your class for observation, and require all observers to implement the MyClassObserver protocol.

3. Objects can now call -addObserver: and -removeObserver: on instances of your class

MyClass *object = [MyClass new];
[object addObserver:self];

...

[object removeObserver:self];

4. Notify observers of events

Use the -notifyObserversWithSelector:parameters: to notify your observers of an event. The selector should match a method declared in your observation protocol.

SEL selector = @selector(myObject:didPerformTaskWithObject:);
NSArray *parameters = @[self, anotherObject];

[self notifyObserversWithSelector:selector parameters:parameters];

The above code will send the specified selector to all of the object's observers, assigning the parameters as parameters to the call.

Hope that you'll enjoy using JSObservableObject!

Why not give me a shout on Twitter: @johnsundell