code: public StateConfiguration<S, T> onEntry(final Action1<Transition<S, T>> entryAction) {
          assert entryAction != null : ENTRY_ACTION_IS_NULL;
          representation.addEntryAction(new Action2<Transition<S, T>, Object[]>() {
              @Override
              public void doIt(Transition<S, T> arg1, Object[] arg2) {
                  entryAction.doIt(arg1);
              }
          });
          return this;
      }
docs: Specify an action that will execute when transitioning into the configured state
  
  @param entryAction Action to execute, providing details of the transition
  @return The receiver