question: protected final boolean parseLine ( Pattern pattern , int timestamp , int hostname , int comp , int pid , int msg , String line ) { final Matcher matcher = pattern . matcher ( line ) ; if ( matcher . matches ( ) ) { try { final String msgTimeStr = toString ( matcher , timestamp ) ; final String source255Chars = toString ( matcher , hostname ) ; if ( source255Chars . length ( ) > 200 ) { m_source = source255Chars . substring ( 0 , 200 ) ; if ( ! isHostnameTruncationLogged ) { logger . info ( "Hostname : \"" + source255Chars + "\"" + " is truncated from " + source255Chars . length ( ) + " to " + m_source . length ( ) + " characters: \"" + m_source + "\"" ) ; isHostnameTruncationLogged = true ; } } else { m_source = source255Chars ; } m_source = m_source . toLowerCase ( ) ; m_msgTime = toDate ( m_source , msgTimeStr ) ; m_component = toString ( matcher , comp ) ; m_pid = toString ( matcher , pid ) ; m_text = toString ( matcher , msg ) ; return true ; } catch ( IllegalArgumentException e ) { e . printStackTrace ( ) ; return false ; } } return false ; }
target:  Parses a line based on a regex Pattern.  For each capturing group number that is non-zero, the corresponding instance variable is set.