question: private void handleControlMessage ( ConnectedClient client , byte [ ] bytes ) { ControlMessage message ; try { message = ControlMessage . parseFrom ( bytes ) ; log . debug ( "Control message from client {}: {}" , client , message ) ; } catch ( InvalidProtocolBufferException e ) { log . warn ( "Bad control message from client {}: {}" , client , e ) ; return ; } for ( ByteString unsubscribe : message . getTopicUnsubscribeList ( ) ) { if ( log . isInfoEnabled ( ) ) { if ( unsubscribe . isValidUtf8 ( ) ) { log . info ( "{} unsubscribing from {}" , client , unsubscribe . toStringUtf8 ( ) ) ; } else { log . info ( "{} unsubscribing from {}" , client , unsubscribe ) ; } } subscriptions . remove ( client , unsubscribe ) ; } for ( ByteString subscribe : message . getTopicSubscribeList ( ) ) { if ( log . isInfoEnabled ( ) ) { if ( subscribe . isValidUtf8 ( ) ) { log . info ( "{} subscribing to {}" , client , subscribe . toStringUtf8 ( ) ) ; } else { log . info ( "{} subscribing to {}" , client , subscribe ) ; } } subscriptions . put ( client , subscribe , true ) ; } }
target:  Handles a control message from a client (publish, subscribe, etc.)