question: private ClientSocket connect ( ) { if ( _maxConnections <= _activeCount . get ( ) + _startingCount . get ( ) ) { if ( log . isLoggable ( Level . WARNING ) ) { log . warning ( this + " connect exceeded max-connections" + "\n  max-connections=" + _maxConnections + "\n  activeCount=" + _activeCount . get ( ) + "\n  startingCount=" + _startingCount . get ( ) ) ; } return null ; } _startingCount . incrementAndGet ( ) ; State state = _state ; if ( ! state . isInit ( ) ) { _startingCount . decrementAndGet ( ) ; IllegalStateException e = new IllegalStateException ( L . l ( "'{0}' connection cannot be opened because the server pool has not been started." , this ) ) ; log . log ( Level . WARNING , e . toString ( ) , e ) ; throw e ; } if ( getPort ( ) <= 0 ) { return null ; } long connectionStartTime = CurrentTime . currentTime ( ) ; try { ReadWritePair pair = openTCPPair ( ) ; ReadStreamOld rs = pair . getReadStream ( ) ; rs . setEnableReadTime ( true ) ; _activeCount . incrementAndGet ( ) ; _connectCountTotal . incrementAndGet ( ) ; ClientSocket stream = new ClientSocket ( this , _streamCount ++ , rs , pair . getWriteStream ( ) ) ; if ( log . isLoggable ( Level . FINER ) ) log . finer ( "connect " + stream ) ; if ( _firstSuccessTime <= 0 ) { if ( _state . isStarting ( ) ) { if ( _loadBalanceWarmupTime > 0 ) _state = State . WARMUP ; else _state = State . ACTIVE ; _firstSuccessTime = CurrentTime . currentTime ( ) ; } if ( _warmupState < 0 ) _warmupState = 0 ; } return stream ; } catch ( IOException e ) { if ( log . isLoggable ( Level . FINEST ) ) log . log ( Level . FINEST , this + " " + e . toString ( ) , e ) ; else log . finer ( this + " " + e . toString ( ) ) ; failConnect ( connectionStartTime ) ; return null ; } finally { _startingCount . decrementAndGet ( ) ; } }
target:  Connect to the backend server.