question: private void initFromAuthHeader ( String authHeader ) { this . authHeader = authHeader ; if ( authHeader == null ) throw new NullPointerException ( "No authentication header information" ) ; Matcher authMatcher = SCHEME_PATTERN . matcher ( authHeader ) ; if ( ! authMatcher . matches ( ) ) { throw new IllegalStateException ( "Unable to parse auth header: " + authHeader ) ; } scheme = authMatcher . group ( 1 ) ; if ( authMatcher . groupCount ( ) > 1 ) { Matcher paramMatcher = PARAM_PATTERN . matcher ( authMatcher . group ( 2 ) ) ; while ( paramMatcher . find ( ) ) { String value = paramMatcher . group ( 2 ) ; if ( value == null ) { value = paramMatcher . group ( 3 ) ; } parameters . put ( paramMatcher . group ( 1 ) , value ) ; } } }
target:  Initializes internal state from the contents of a WWW-Authenticate header.