abstract class EntityActivity extends Activity{
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		if (isOnline()) {
			doSomethingWhereWeAreOnline();
		} else {
			offlineRun(getClass());
		}
	}

	protected abstract void doSomethingWhereWeAreOnline();
}

class MyActivity extends EntityActivity {
	@Override
	protected void doSomethingWhereWeAreOnline() {
		setContentView(R.layout.main);
	}
}