pool

For pooling and caching objects which are costly to create.

##Install

Usage

(use 'pool.core)

Object Pool

get-pool takes a no argument function for object creation.

(def pool (get-pool (fn [] :heavy-object)))

Next, borrow and return from pool.

(borrow pool) ;=> :heavy-object
(return pool :heavy-object)

###Keyed Object Pool get-keypool takes a single arity function for object creation.

(def pool (get-keypool (fn [k] (str :heavy k))))

(borrow pool :object) ;=> ":heavy:object"
; Return key and object
(return pool :object ":heavy:object")

get-pool and get-keypool takes optional kwargs for destory, validate, activate and passivate for finer control of object creation and deletion.

Caching

Caching although a different concept is provided in the library for caching objects which are threadsafe in themselves and thus can be shared instead of pooled, but are very costly to create.

get-cache and get are the only available methods to work with. get-cache take a single arity function on key for object creation.

(require '[pool.cache :as c])
(def cache (c/get-cache (fn [k] (print "once!") (Thread/sleep 1000) k)))
(c/get cache 1) ;=> once! 1

; Safeguards against multiple threads.
(defn double-write [x] (future (c/get cache x)) (future (c/get cache x)))
(double-write 5) ;=> once! ...

License

Copyright © 2014 kul

Distributed under the Eclipse Public License.