Cache

Cache.swift

import Foundation

public struct Cache<ValueType> {
    typealias KeyType = String
    private class Box<T>: NSObject {
        let value: T
        init(_ value: T) {
            self.value = value
            super.init()
        }
    }

    private let cache = NSCache<NSString, Box<ValueType>>()

    public func object(forKey key: KeyType) -> ValueType? {
        return cache.object(forKey: key as NSString)?.value
    }

    public func setObject(_ obj: ValueType, forKey key: KeyType) {
        cache.setObject(Box(obj), forKey: key as NSString)
    }

    public func removeObject(forKey key: KeyType) {
        cache.removeObject(forKey: key as NSString)
    }

    public func removeAllObjects() {
        cache.removeAllObjects()
    }
}

let myCache = Cache<Bool>()
myCache.setObject(true, forKey: "foo")
myCache.object(forKey: "foo")
myCache.removeObject(forKey: "foo")
myCache.object(forKey: "foo")