Get generic parameter of unknown collection object

Hey guys, I've been trying to create a system which allows you to load certain variables from a config automatically. So I made a couple of converters for specific types and also one for a collection, but that's not as easy as I thought. I have to check if the generic parameter of the collection variable in the class is the same as the generic parameter of the object the config returns me, but I can't figure out how I can access that parameter. So for example Object o = new ArrayList<String>() would return the String class as generic parameter. I've already tried things like ((ParameterizedType) o.getClass().getGenericSuperclass()).getActualTypeArguments()[0] but that only returns sun.reflect.generics.reflectiveObjects.TypeVariableImpl instead of the actual type. This method only works if I define it like this List<String> o = new ArrayList<String>() which is pointless for me :/

 

I'm assuming you got the line of code you posted from here. If that's the case, then it looks like you just need to cast it to List<T>.

 

ShadyPotato That doesn't work, here's my current method which converts an object from the config to a collection:

Code:java

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static <V, T extends Collection<V>> T convert(Collection<?> source, Class<?> type) throws ConversionException {
        try {
            T result;
            if (type.isInterface() || Modifier.isAbstract(type.getModifiers())) {
                if (Set.class.isAssignableFrom(type)) {
                    if (SortedSet.class.isAssignableFrom(type))
                        result = (T) new TreeSet();
                    else
                        result = (T) new HashSet();
                } else
                    result = (T) new ArrayList();
            } else
                result = (T) type.newInstance();
            Converter<V> converter = null;
            for (Object value : source) {
                if (converter == null)
                    converter = (Converter<V>) ConversionHandler.getConverter(value.getClass());
                result.add(converter.convert(value));
            }
            return result;
        } catch (Exception e) {
            throw new ConversionException(type, e);
        }
    }

But currently I have no check if the generic parameter of the source matches with the actual type.

 

Does anyone know how to solve this?