code: private String getStandardAction(String id, HttpMethod requestMethod) {
  		String action = null;
  		if (requestMethod == HttpMethod.GET) {
  			if (id == null) {
  				action = INDEX_ACTION;
  			} else {
  				action = SHOW_ACTION;
  			}
  		} else if (requestMethod == HttpMethod.POST) {
  			action = CREATE_ACTION;
  		} else if (requestMethod == HttpMethod.DELETE) {
  			action = DESTROY_ACTION;
  		} else if (requestMethod.equals(HttpMethod.PUT)) {
  			action = UPDATE_ACTION;
  		}
  		return action;
  	}
docs: Deduces the action invoked when there isn't action in the URL. The action
  is deduced by the HTTP_METHOD used. If method is GET, it also has in
  count the ID, because it depends on it to know if action is 'show' or
  'index'.<br/>
  <br/>
  GET: with ID => show, without ID => index.<br/>
  POST: create.<br/>
  DELETE: delete.<br/>
  PUT: update.<br/>
  <br/>
  
  @param id
  Identifier, if any.
  @param requestMethod
  HTTP METHOD (GET, POST, PUT, DELETE).
  
  @return an action.