code: public StateConfiguration<S, T> onEntryFrom(T trigger, final Action entryAction) {
          assert entryAction != null : ENTRY_ACTION_IS_NULL;
          return onEntryFrom(trigger, new Action1<Transition<S, T>>() {
              @Override
              public void doIt(Transition<S, T> arg1) {
                  entryAction.doIt();
              }
          });
      }
docs: Specify an action that will execute when transitioning into the configured state
  
  @param trigger     The trigger by which the state must be entered in order for the action to execute
  @param entryAction Action to execute
  @return The receiver