Endless event-style methods for Components

ComponentHolder.java

public class ComponentHolder {
    // ...
    public void onEvent(String methodName) {
        for (Component c:getComponents()) {
            if (c.getClass().hasMethod(methodName)) {
                c.getClass().getMethod(methodName).execute(c);
            }
        }
    }
    // ...
}

GuiComponent.java

public class GuiComponent extends Component {
    public void onBuy() {
        updateGui();
    }
}

TradeComponent.java

public class TradeComponent extends Component {
    @Override
    public void onTick() {
        if (someCondition) {
            getHolder().onEvent("onBuy");
        }
    }
}