【荒于嬉】common pool2 源码阅读纪要

BEGIN

IF removeAbandon configured
  IF removeAbandonOnBorrow and idleNum<2 and activeNum>maxNum-3
    do removeAbandon
  END IF
END IF

WHILE p equals null
DO
  LET create=false
  poll first elements from idleObjects, let p=result.
  IF p still null
    try create p
    IF p not null
      let create=true
    END IF
  END IF
  
  IF blockWhenExhausted and p still null
     bocking poll first element of idleObject
     if maxWaitTime less than 0, block until there is at least one idle object.
     IF p still null, throw NoSuchElementException.
  END IF
  
  if p still null, throw NoSuchElementException.
  try allocate p, if result is false, let p=null.
  
  IF p not null
    try activate p
    IF exeption happens, destroy p and throw exception.
    IF testOnBorrow or testOnCreate
      try validate p, if exception happens, record it.
      if validation fails, destroy it and throw exception when it is created.
    END IF
  END IF
  
END WHILE

update pool borrow related statistic stats.

END

BEGIN
  get PooledObject p from allObjects with to be returned.
  IF p is null
    IF abandon configured, return
    ELSE throw exception.
  END IF
  
  mark the status of p to RETURNING.
  
  IF testOnReturn and validate p failed.
    try destroy p.
    ensure that there is at least one idle object in the pool.
    update pool's return related statistic status.
  END IF
  
  try passivate p.
  
  deallocate p and update its status to IDLE.
  
  IF pool closed or current idle counts is more than maxIdle
    try destroy p.
  ELSE
    add p to idleObjects queue.
    IF pool closed, clear the pool.
  END IF
  
  update pool's return related statistic status.
END