text book exercise example

[prerthan99]

given the question below, are the 2 diagrams correct and equivalent? If so, how can we show visibility (private, public, static) in the first option. and also, how do we show that the expected output type for open is void? Is it open() = void ?

Question:

Ans:

[tlylt]

Thanks for sharing!

• multiplicity
  • lid and box (outerbox as well), item is wrong, given that they are variables, it should be 0..1, and not *
  • parts should be 0..10
• totalItems is not an association to itself, it is just a class variable
• also the question does not require the visibility

edit: see https://github.com/nus-cs2103-AY2021S2/forum/issues/352#issue-865050502, there is a video in week 8 or 9 that goes through the design process for this exact question

[damithc]

To add, it's not possible to show visibility for associations shown as lines (within the scope of notations we cover in the module). Visibility is not that important anyway (compared to showing relationships between classes). Option 1 is still more useful than option 2 as a visual model of the design even if it doesn't show visibility.

[prerthan99]

i was wondering if the arrow linking Box and lid should be bidirectional eg: lid 0..1 <------------------------> box 0..1? thank you

[tlylt]

@prerthan99

[prerthan99]

ah ok. thank you.