Question

I have the following method signature, how do i convert it to be a template.

public static JSONContainer getMappedRootObject(JSONContainer clazz, String filename) {
    ...
    JSONContainer container = new Gson().fromJson(br, JSONContainer.class);
    return container;
}

This is what i came up with, is this right?

public static <T extends Object> T getMappedRootObject(Class<T> clazz, String filename) {
    T container = new Gson().fromJson(br, clazz);
    return container;
}

Answer 1

If in your JSONContainer implementation, the “JSONContainer clazz” parameter is an instance of the target object, you may do the following:

public static <T> T getMappedRootObject(T instance, String filename) {
     //.......

    if (instance == null) {
        // handle this
    } else {
        T container = new Gson().fromJson(br, instance.getClass());
        return container;
    }
}