question: public String addManager ( ) throws Exception { if ( resource == null ) { return NOT_FOUND ; } User u = userManager . get ( id ) ; if ( u != null && ! potentialManagers . contains ( u ) ) { addActionError ( getText ( "manage.overview.manager.not.available" , new String [ ] { id } ) ) ; } else if ( u != null ) { resource . addManager ( u ) ; addActionMessage ( getText ( "manage.overview.user.added" , new String [ ] { u . getName ( ) } ) ) ; saveResource ( ) ; potentialManagers . remove ( u ) ; } return execute ( ) ; }
target:  Triggered by add manager button on manage resource page.