dimanche 31 mai 2015

Java reflection class cast exception on generic instance

I want to get instance of generic using reflection:

        this.wrapperInstance = ((Class<WRAPPER>) ((ParameterizedType) (getClass().getGenericSuperclass())).getActualTypeArguments()[1]).newInstance();

but I get exception:

java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType

Do not know where is problem, maybe someaone can help me? There is full class code:

public class XMLUtils<MODEL extends AbstractModel, WRAPPER extends WraperInterface<MODEL>> {

private WRAPPER wrapperInstance;

@SuppressWarnings("unchecked")
public XMLUtils() throws InstantiationException, IllegalAccessException {
    this.wrapperInstance = ((Class<WRAPPER>) ((ParameterizedType) (getClass().getGenericSuperclass())).getActualTypeArguments()[1]).newInstance();
}

@SuppressWarnings("unchecked")
public List<MODEL> loadDataFromXML(String fileName) {

    try {

        File pajamuFile = new File(
                UserDataLoader.INSTANCE.getCurrentUserFolder() + fileName);
        JAXBContext context = JAXBContext.newInstance(wrapperInstance.getClass());
        Unmarshaller um = context.createUnmarshaller();
        WRAPPER wrapper = (WRAPPER) um.unmarshal(pajamuFile);
        return wrapper.getDataList();
    } catch (JAXBException e) {
        e.printStackTrace();
        return new ArrayList<MODEL>();
    }
}

public void saveDataToXML(List<MODEL> dataList, String fileName) {
    try {

        File pajamuFile = new File(
                UserDataLoader.INSTANCE.getCurrentUserFolder() + fileName);
        JAXBContext context = JAXBContext.newInstance(wrapperInstance.getClass());
        Marshaller m = context.createMarshaller();
        WRAPPER wrapper = wrapperInstance;
        wrapper.setDataList(dataList);
        m.marshal(wrapper, pajamuFile);
    } catch (JAXBException  e) {
        e.printStackTrace();
    }
}

}

In google I find most such like situation but with spring, here I am not using spring, so maybe there is any clear solution for that what I want to do.





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