public void addPrincipal(String principal) {
        if (!readOnly && !principals.contains(principal)) {
            principals.add(principal);
            principalsModified = true;
        }
    }
public void addPrincipal ( String principal ) { if ( ! readOnly && ! principals . contains ( principal ) ) { principals . add ( principal ) ; principalsModified = true ; } }
add a principal to this authorizable.
@param principal