void function ( ActionEvent arg0 ) { }
updates the state of the action . default implementation does nothing . override this method to provide the ability to dynamically change action 's state and or presentation depending on the context for example when your action state depends on the selection you can check for selection and change the state accordingly . this method can be called frequently , for instance , if an action is added to a toolbar , it will be updated twice a second . this means that this method is supposed to work really fast , no real work should be done at this phase . for example , checking selection in a tree or a list , is considered valid , but working with a file system is not . if you can not understand the state of the action fast you should do it in the #actionperformed actionevent method and notifythe user that action can not be executed if it 's the case . concode_field_sep Presentation presentation concode_field_sep Presentation getTemplatePresentation concode_elem_sep void actionPerformed concode_elem_sep String toString