List, ArrayList and Generics as UML

[Dan Drillich]

Good Day,

I'm trying to draw the following in a UML class diagram.

List<Map<String, String>> DATA_SET = new ArrayList<Map<String, String>>();

How do you think it should look like?

Regards,
Dan

[matt love]

Hi Dan.

Thanks for answering my question on operators.

Do you have this topic in the right category?

Thanks again.

Matt

[Dan Drillich]

Hi Matt, I think you are right. It probably should be moved someplace else ; - )

Regards,
Dan

[Mohamed Sanaulla]

I have moved this topic to a more suitable forum.

[Ryan McGuire]

Dan Drillich wrote:Good Day,

I'm trying to draw the following in a UML class diagram.

List<Map<String, String>> DATA_SET = new ArrayList<Map<String, String>>();

How do you think it should look like?

Regards,
Dan

Take a look a the third diagram (Figure 6-20) on this page.

    T
Set  <--------------------- EmployeeSet
       <<bind>> <Employee>     

I think your nested generic would have to be notated in two pieces:

   T1,T2
Map     <--------------------------- StringStringMap
          <<bind>> <String,String> 


    T                                     
List <------------------------------  StringStringMapList
        <<bind>> <StringStringMap>

The question is could you do that without having to come up with a name for the intermediate Map<String,String> class?

Then again, Figure 6-19 on that page shows the generic type just written out as the class name. That seems to imply that you could use List<Map<String,String>> as the name of the class without having to use the parameterized class notation or defining a new class (such as EmployeeSet in Fig 6-20).

EDIT: Of course it might help if I actually responded to your question. :-)

I'd show the super/sub-class relation between List<> and ArrayList<>, both as parameterized classes, and then show another class (perhaps anonymous) as a bound element of ArrayList<> with the template parameter bound to Map<String,String>.

    T                                T
List <|-------------------- ArrayList <-------------------------------- StringStringMapArrayList
        (is a subclass of)              <<bind>> <Map<String,String>>

Then DATA_SET is an instance of class StringStringMapArrayList.

That combines the two notations given in the page I mentioned earlier. It uses the simple C++, as that page calls it, notation for Map<String,String>but then uses the more verbose parameterized class notation to show the relations between the List and ArrayList generics.

EDIT2:
Oops... I forgot List is "just" an interface. That modifies class diagram just a touch:

             T  
<<interface>>                          T
    List      <|------------- ArrayList <-------------------------------- StringStringMapArrayList
                 (implments)              <<bind>> <Map<String,String>>