code: public void updateButtons() {
  
          for (Button button : new Button[] {m_forward, m_fastForward}) {
              button.setEnabled(m_page < m_lastPage);
          }
          for (Button button : new Button[] {m_back, m_fastBack}) {
              button.setEnabled(m_page > 0);
          }
      }
docs: Updates the button state, i.e. enables/disables the buttons depending on whether we are on the first or last page or not.<p>