question: public boolean removeAuth ( String userName , String password , String indexName ) { if ( userName == null || userName . equals ( "" ) || indexName == null || indexName . equals ( "" ) ) { return false ; } userName = userName . toLowerCase ( ) ; indexName = indexName . toLowerCase ( ) ; if ( userName . equals ( "root" ) ) { return false ; } UserData user = getUser ( userName ) ; if ( user == null ) return false ; if ( user . isValidPassword ( password ) ) { Set < String > indices = user . getIndexFilters ( ) ; if ( indexName . charAt ( 0 ) != '/' ) { indexName = "/" + indexName ; } if ( indices . contains ( indexName ) ) { indices . remove ( indexName ) ; putUser ( user ) ; return true ; } } return false ; }
target:  add permission to an user with a specified index