Question

I imagine that there has to be some way to use reflection to do what I want to do.

I need to be able to take a string at runtime that is of a certain class, for example:

string s = "mypackage.MySuperClass"

Then I may have an object of some type. It could be one of the following:

mypackage.MySuperClass obj = new mypackage.MySuperClass();

or

mypackage.MySubClass obj2 = new mypackage.MySubClass();

or

someotherpackage.SomeOtherClass obj3 = new someotherpackage.SomeOtherClass();

What I need to do is see if an object (which its type is determined at runtime), is equal to the string s (which is also determined at runtime via completely different means).

In the cases above I would want obj and obj2 to be the same type as s (since MySubClass is a subclass of MySuperClass), and obj3 would not.

Is there an easy way to do this in java? Possibly something using instanceOf?

Answer 1

Sounds like you want something like this:

boolean isInstance(Object o, String className) {
    try {
        Class clazz = Class.forName(className);
        return clazz.isInstance(o);
    } catch (ClassNotFoundException ex) {
        return false;
    }
}

Or you could do it the other way round – take o’s class (o.getClass()), find all ancestor classes and compare their names to className.