private void validateFields ( List < String > fields ) { if ( fields == null ) { return ; } List < String > badFields = new ArrayList < String > ( ) ; for ( String field : fields ) { if ( field . contains ( "." ) ) { badFields . add ( field ) ; } } if ( ! badFields . isEmpty ( ) ) { String msg = String . format ( "Projection field(s) cannot use dotted notation: %s" , Misc . join ( ", " , badFields ) ) ; logger . log ( Level . SEVERE , msg ) ; throw new IllegalArgumentException ( msg ) ; } }
Checks if the fields are valid .