static void addActionListener(JTextField tf, final Runnable action) { onEnter(tf, action); } static void addActionListener(final JComboBox cb, final Runnable action) { if (cb != null) swing { cb.addActionListener(actionListener(action)); } } static void addActionListener(final AbstractButton b, final Runnable action) { if (b != null) swing { b.addActionListener(actionListener(action)); } }