         
         #if !os(OSX) && !os(watchOS)
             NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(DataCache.cleanExpiredDiskCache), name: UIApplicationWillTerminateNotification, object: nil)
-            NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(DataCache.backgroundCleanExpiredDiskCache), name: UIApplicationDidEnterBackgroundNotification, object: nil)
+            NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(DataCache.cleanExpiredDiskCache), name: UIApplicationDidEnterBackgroundNotification, object: nil)
         #endif
     }
     

    
    // MARK: Clean
    
    @objc private func cleanExpiredDiskCache() {
        
    }
    
    @objc private func backgroundCleanExpiredDiskCache() {
        
    }
    
    // MARK: Utils
    
    private func cachePathForKey(key: String) -> String {
        return (cachePath as NSString).stringByAppendingPathComponent(key)

    private let fileManager: NSFileManager! = nil
    
    public var name: String = ""
    public var maxCachePeriodInSecond = DataCache.defaultMaxCachePeriodInSecond
    
    // size allocate for disk cache, in byte
    public var maxDiskCacheSize: UInt = 0
    
    public init(name: String, path: String? = nil) {
        self.name = name
