IndexedSetInterface is an interface which defines a set(int, Object) method,
commonly used for setting or storing items into
indexed collections of objects.
The object must also implement the Countable interface which
defines the valid range of indices. Most objects use
zero based indexing and thus the valid set of indices
would be 0..count()-1.
Usage
for (int i = 0, count = x.count(); i < count; i++) {
// for some object o, store it with the index i
x.set(i, o);
}