NSNotificationCenterのラッパー

Notification.swift

import Foundation

class Notification {
    
    // MARK: - Singleton
    
    struct Static {
        static let instance = Notification()
        static let queue = dispatch_queue_create("Notification.Static.instance.cache", DISPATCH_QUEUE_SERIAL)
    }
    
    var cache = [UInt:[NSObjectProtocol]]()
    
    // MARK: - addObserverForName
    
    class func on(target: AnyObject, name: String, queue: NSOperationQueue?, handler: ((NSNotification!) -> Void)) {
        let id = ObjectIdentifier(target).uintValue()
        
        dispatch_sync(Static.queue) {
            let observer = NSNotificationCenter.defaultCenter().addObserverForName(name, object: nil, queue: queue, usingBlock: handler)
            if let observers = Static.instance.cache[id] {
                Static.instance.cache[id] = observers + [observer]
            } else {
                Static.instance.cache[id] = [observer]
            }
        }
    }
    
    class func onMainThread(target: AnyObject, name: String, handler: ((NSNotification!) -> Void)) {
        Notification.on(target, name: name, queue: NSOperationQueue.mainQueue(), handler: handler)
    }
    
    class func onBackgroundThread(target: AnyObject, name: String, handler: ((NSNotification!) -> Void)) {
        Notification.on(target, name: name, queue: NSOperationQueue(), handler: handler)
    }
    
    // MARK: - removeObserver
    
    class func off(target: AnyObject) {
        let id = ObjectIdentifier(target).uintValue()
        
        dispatch_sync(Static.queue) {
            if let observers = Static.instance.cache[id] {
                for observer in observers {
                    NSNotificationCenter.defaultCenter().removeObserver(observer)
                }
                Static.instance.cache.removeValueForKey(id)
            }
        }
    }
    
    // MARK: - postNotificationName
    
    class func post(name: String) {
        NSNotificationCenter.defaultCenter().postNotificationName(name, object: nil)
    }
    
    class func post(name: String, userInfo: [NSObject : AnyObject]?) {
        NSNotificationCenter.defaultCenter().postNotificationName(name, object: nil, userInfo: userInfo)
    }
    
}

NotificationTests.swift

import Foundation
import XCTest

class NotificationTests: XCTestCase {
    
    override func setUp() {
        super.setUp()
        Notification.off(self)
    }
    
    override func tearDown() {
        Notification.off(self)
        super.tearDown()
    }
    
    func testOnMainThread() {
        Notification.onMainThread(self, name: "testOnMainThread", handler: { _ in
            XCTAssertTrue(NSThread.isMainThread())
        })
        Notification.post("testOnMainThread")
    }
    
    func testOnBackgroundThread() {
        Notification.onBackgroundThread(self, name: "testOnBackgroundThread", handler: { _ in
            XCTAssertTrue(NSThread.isMainThread() == false)
        })
        Notification.post("testOnBackgroundThread")
    }
    
    func testOff() {
        
        var counter = 0
        
        let handler = { (n: NSNotification!) -> Void in
            counter++
            return
        }
        
        Notification.onMainThread(self, name: "testOffCounter", handler: handler)
        
        Notification.post("testOffCounter")
        Notification.post("testOffCounter")
        
        Notification.off(self)
        
        Notification.post("testOffCounter")
        Notification.post("testOffCounter")
        
        Notification.onMainThread(self, name: "testOffCounter", handler: handler)
        
        Notification.post("testOffCounter")
        Notification.post("testOffCounter")
        
        Notification.onMainThread(self, name: "testOffVerify", handler: { _ in
            XCTAssertEqual(counter, 4)
        })
        Notification.post("testOffVerify")
    }
}