UML class diagram reference: for group function of a webapp. (like facebook group)

0
votes

I am looking for some existing references of the UML class diagram that is model for "group function of a webapp system", like facebook group or meetup.com etc.

basically, creating groups, request joining groups, accept , reject, create events in the group, join events..etc.

I just want to see how ppl model that specific part of the web app (group functions), and see some common references of what would be a good way to model that!

I have hand draw a class diagram -enter image description here

what I am trying to model is:

  1. User can join 0 to many groups
  2. Group can have 1 to many users
  3. Group has 0 to many events
  4. User can be invited to the event of their group, the user can accept / reject..etc.
  5. Group can send their event (activity) to other groups and they can also accept / reject .etc.
2
uml

2 Answers

0
votes
  1. Class diagrams are STRUCTURE diagrams. And you are talking about behaviour. It is extremely inconvenient to show behaviour in class diagrams. Start from use cases and go to activity diagrams.
  2. UML is a language set, supporting modelling. Not modelling in some specific language, let alone programming language or specific framework. I sometimes use class diagrams for modelling UI design or user guides. UML diagrams look the same, no regard to use of facebook.
  3. Facebook programming is a use of a framework, supporting creation some kinds of IS, with some ready functionalities. If you want to make a class diagram supporting such modelling, simply use the facebook classes as ready ones and derive your classes from them.

Edit. As reaction to your diagram (please, put its reference into the question):

  • Two-sided shared aggregation is forbidden in UML standard. I see, it HAS sense, but you must write it as two connections.
  • Group-event connection has diamond on the wrong end.
  • Group or User or both should have invite method
  • What user can do is to be set in use case or state diagram, not in class diagram. The same for your rule 5

Again - you should start from UC diagram or state diagram.

0
votes

I can't access your drawing, so i can't see what you have done.

As a starting point, this shows the entities, relationships and cardinalities.

enter image description here

I have not included a relationship between user and event, because this is implicit through group. You may or may not want to visually draw in that relationship.

This only shows the static structure of the system and does not show the dynamic aspects.