question: public void pingReceived ( Ping pong ) { long now = System . currentTimeMillis ( ) ; long previousReceived = ( int ) ( lastPingSent . get ( ) & 0xffffffff ) ; log . debug ( "Pong from client id {} at {} with value {}, previous received at {}" , new Object [ ] { getId ( ) , now , pong . getValue2 ( ) , previousReceived } ) ; if ( pong . getValue2 ( ) == previousReceived ) { lastPingTime . set ( ( int ) ( now & 0xffffffff ) - pong . getValue2 ( ) ) ; } lastPongReceived . set ( now ) ; }
target:  Marks that ping back was received.