Casting, objects, and wrappers

[Charles McGuire]

I have an object. If I know it is an Integer, can I cast the object to Integer in order to execute a method on it?

if (obj instanceof Integer) {
   int count = (Integer)obj.intValue();
 }

This is giving me the error: the method intValue() is undefined for the type object. Yet, I thought the cast to (Integer) would do that. I have what must be an inefficient work around. Yuck.

if (obj instanceof Integer) {
   Integer tempI = new Integer(obj.toString());
   int count = tempI.intValue();
 }

Yuck. If I know obj is of type Integer (from the instanceof test), how do I execute methods of Integer on that object??

[Ernest Friedman-Hill]

You just need some more parentheses. "(Integer) obj.intValue()" means to call intValue() on obj, and cast the result to Integer. On the other hand, "((Integer) obj).intValue()" means to cast obj to Integer, and call intValue() on that Integer.

[Charles McGuire]

Thank you!!!

I feel like an idiot. Thrice an idiot:

Once for not knowing this.
Again for not finding this in my hard copy reference books.
Again for not being able to construct a forum search string to find this (I looked).