Observable V2

observable_v2.swift

import Foundation

protocol Observable: class {
    
    associatedtype ObservableAction
    
    typealias SubscriptionBlock = (ObservableAction) -> Void
    
    var subscriptions: NSMapTable<AnyObject, AnyObject> { get set }
    func notifyObservers(_ action: ObservableAction) -> Void
    func addObserver(_ observer: AnyObject, block: SubscriptionBlock) -> Void
    func removeObserver(_ observer: AnyObject) -> Void
    
}

extension Observable {
    
    func notifyObservers(_ action: ObservableAction) -> Void {
        let enumerator = self.subscriptions.objectEnumerator()
        
        while let value = enumerator?.nextObject() {
            let subsriptionBlock = value as! SubscriptionBlock
            subsriptionBlock(action)
        }
    }
    
    func addObserver(_ observer: AnyObject, block: SubscriptionBlock) -> Void {
        self.subscriptions.setObject(block as AnyObject?, forKey: observer)
    }
    
   func removeObserver(_ observer: AnyObject) -> Void {
        self.subscriptions.removeObject(forKey: observer)
    }
    
}

enum TestObservableActions {
    case testAction
}

class TestObservable: Observable {
    internal var subscriptions: NSMapTable<AnyObject, AnyObject> = NSMapTable.weakToWeakObjects()
    typealias ObservableAction = TestObservableActions
    
    func testFunc() -> Void {
        self.notifyObservers(.testAction)
    }
}

class TestObserver {
    
    internal func observe(_ action: TestObservableActions) {
        print("Action: \(action)")
    }
    
}

func test() -> Void {
    let testObservable = TestObservable()
    let testObserver = TestObserver()
    
    testObservable.addObserver(testObserver, block: testObserver.observe)
    testObservable.testFunc()
}