So we've, we've been over constraints, we've been over navigation, the third main element of OCL is collections. I've hinted at what that is. There's, there's four built in collection classes.
We already talked about sets, and bags, and sequences a little bit. There's an abstract class that sits above them all called the collection class. These four classes are organized with the collection class being a parent class, and the collection class has various operators such as, size which we saw and count, and sums, and ways of interrating over the collection and so on.
That are inherited by all of the three other collection classes. Moreover, those collection classes, those three other concrete collection classes may themselves have some specialized operations.
