question: private int parseMessageId ( final byte [ ] b , final int off ) throws ParseException { final int messageIdLen = Constants . MESSAGE_ID_LEN ; final int len = b . length - off ; if ( len >= messageIdLen ) { messageId_ = Arrays . copyOfRange ( b , off , off + messageIdLen ) ; return messageIdLen ; } else { throw new ParseException ( "Not enough bytes to parse serial number" ) ; } }
target:  Parse the message ID in the provided bytes. It looks for bytes of the size defined by the message identifier length in the provided bytes starting at the specified off. <p> If successful, it returns the number of parsed bytes which is the message identifier length. On failure, it throws a parse exception.