Generic Gson Help

[Jacob]

I have a model

class Envelope<T> {
public int version;
public T data;
}

Many many services share the envelope and I want to provide a shared
method for marshalling it. I have tried the following

protected final <T> String buildResult(T result, int version) {
Envelope<T> env = new Envelope<T>();
env.setData(result);
env.setVersion(version);
return new Gson().toJson(env, new TypeToken<Envelope<T>>() {
}.getType());
}

This compiled but fails a runtime with
java.lang.IllegalArgumentException: Type 'T' is not a Class,
ParameterizedType, or GenericArrayType. Can't extract class.

Is there a way to do this without making the type a parameter? I am
more to willing to say my knowledge of generics in Java is weak.

Jacob

[inde...@gmail.com]

This can not be done. The TypeToken trick needs actual classes, not
type variables.

You would need to change buildResult to take the class or type
parameter corresponding to T.