Presenter { public final void dropView(@Nonnull V view) { requireNotNull(view); if (currentView() == view) { onDropView(view); getProxy(viewProxy).clear(); } } protected  Presenter(@Nonnull V view); protected  Presenter(); final void dropView(@Nonnull V view); final boolean hasView(); final void takeView(@Nonnull V view);  }
@Test public void droppedViewShouldNotBeNull() { checkIllegalArgumentException(() -> presenter.dropView(null)); }