CacheIsKing

CacheIsKing is a simple cache that allows you to store any item, including objects, pure Swift structs, enums (with associated values), etc. Simply put, it’s designed to act like an NSCache for everything, including Swift variables.

Features

• Simply set, get, and remove items based on any key that is Hashable
• The cache is cleared when the app receives a memory warning
• Similar to NSCache, the cache is cleared when the app enters the background
• Subscripts are supported for String, Int, and Float keys
• itemForKey uses generics so you don’t have to cast the return value when the type is inferred correctly
• Similar to NSCache, the cache can have a countLimit set to ensure that the cache doesn’t get too large

Requirements

• iOS 8.0+
• tvOS 9.0+
• Xcode 7+

Usage

Simply use the KingCache class similar to how you’d use a NSCache. Using the setItem and itemForKey methods allow you to use type inference to get the values you want.

let cache = KingCache()
cache.setItem(123, forKey: "123")

if let item: Int = cache.itemForKey(456) {
    doSomethingWithItem(item)
}

You can also use subscripts to set/get items from the cache. Unfortunately since Swift doesn’t support subscript methods with generics yet, you’ll have to cast your items as necessary. Also currently only String, Int, and Float keys are supported:

let cache = KingCache()
cache["123"] = 123

if let item = cache[456] as? Int {
    doSomethingWithItem(item)
}

The KingCache also has a countLimit property, which allows you to set the maximum number of items in the cache. It currently evicts randomly until the countLimit is met.

let cache = KingCache()
cache.countLimit = 2

cache[123] = 123
cache[234] = 234
cache[345] = 345

print("\(cache.count)") // shows a count of 2

TODO

• Refine eviction algorithm (currently evicts randomly)
• Update with better subscript support once Swift supports subscripts with generics