[Cs3] UML Notation

[Mikhail Nesterenko]

> 
> I have a quick question related to UML. Do the reference lines need to have
> an aggregation/composition diamond associated with it?

Reference lines need compoisition/aggregation diamond when the
referenced object is indeed aggregated, that is it is logically part
of the aggreagtor. A simple reference (pointer) line does not need a
diamond.


> Also related to this in the command design pattern diagram and the history
> example, how is the concrete command associated with the receiver?

According to the UML diagram on slide 4, the concrete command has a
reference (note, does not aggregate, just has a pointer to) the
receiver so that a command can execute an action on the receiver.

On the other hand, invoker, aggreages (abstract) commands.

Thanks,
--
Mikhail