pool.clj

(ns pool
  (:import
   (org.apache.commons.pool2 ObjectPool BasePooledObjectFactory PooledObjectFactory)
   (org.apache.commons.pool2.impl DefaultPooledObject GenericObjectPool GenericObjectPoolConfig)))

(set! *warn-on-reflection* true)

;; таймаут?  W
;; как останавливать? W
;; как плавно расти?
;; как плавно скукоживаться?


(def factory
  (reify PooledObjectFactory
    (makeObject [_]
      (locking prn
        (prn :make))
      (let [obj (Object.)]
        (DefaultPooledObject. obj)))
    (activateObject [_ p]
      (locking prn
        (prn :activate p)))
    (destroyObject [_ p]
      (locking prn
        (prn :destroy p)))
    (passivateObject [_ p]
      (locking prn
        (prn :passivate p)))
    (validateObject [_ p]
      (locking prn
        (prn :validate p))
      true)))

(def config
  (doto (GenericObjectPoolConfig.)
    (.setMaxWait (java.time.Duration/ofSeconds 2))
    (.setTimeBetweenEvictionRuns  (java.time.Duration/ofSeconds 5))
    (.setSoftMinEvictableIdleTime (java.time.Duration/ofSeconds 1))))

(def ^ObjectPool pool (GenericObjectPool. factory config))

(let [o (.borrowObject pool)]
  (try
    o
    (finally
      (.returnObject pool o))))

(dotimes [_ 40]
  (future
    (let [o (.borrowObject pool)]
      (try
        o
        (finally
          (.returnObject pool o))))))

(dotimes [_ 20]
  (let [o (.borrowObject pool)]
    (try
      o
      (finally
        (.returnObject pool o))))
  (Thread/sleep 2000))




(.close pool)


(.getNumActive pool)
(.getNumIdle pool)


GenericObjectPoolConfig/DEFAULT_DURATION_BETWEEN_EVICTION_RUNS
GenericObjectPoolConfig/DEFAULT_SOFT_MIN_EVICTABLE_IDLE_DURATION
(.toSeconds GenericObjectPoolConfig/DEFAULT_EVICTOR_SHUTDOWN_TIMEOUT)