Jagepard / JavaDesignPatterns-Mediator

public class Mediator implements MediatorInterface {

    LinkedHashMap<String, AbstractListener> listeners = new LinkedHashMap<>();

    LinkedHashMap<String, String> events = new LinkedHashMap<>();

    @Override

    public void addListener(AbstractListener listener, String methodToCall) {

        String name = listener.getClass().getName();

        if (listeners.containsKey(name) && events.containsKey(name)) {

            throw new IllegalArgumentException(name + " already exists");

        }

        listeners.put(name, listener);

        events.put(name, methodToCall);

    }

    @Override

    public String notify(String name, HandlerInterface handler) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {

        if (listeners.containsKey(name) && events.containsKey(name)) {

            AbstractListener listener = listeners.get(name);

            String methodName = events.get(name);

            Method method = listener.getClass().getMethod(methodName, HandlerInterface.class);

            return (String) method.invoke(listener, handler);

        }

        return null;