CODEWITHSUNDEEP
javareflection
More Than Five
More Than Five

Reputation: 10419

Check if a class is an instance of list

I need to get all methods in a class that can return a List and then, check for all those method what type of List it is. When I get that type, I need to check if it is an implementation of a particular interface.

I do: 

Person person = new Person();
Class c = person.class;
for (Method m: c.getDeclaredMethods()) {
    // this gets me all the getters
    if (m.getParameterTypes().size() == 0) {
        Class<?> returnType = m.getReturnType()
        if (returnType.equals(java.util.List.class)) {
              // Can get here
              // But how to get the class that is used to parameterise the 
              // list.
        }
    }
}

How do I get the Class that is used to parameterise a List?

Upvotes: 0

Views: 44

Answers (1)

Andy Turner
Andy Turner

Reputation: 140318

Instead of m.getReturnType(), use m.getGenericReturnType().

This gives you back a Type. You then need to test if this is an instance of ParameterizedType: if it is, cast, and extract the type parameters using getActualTypeArguments().

Upvotes: 1

Related Questions