在UML类图中，如何指定类的实际类型？

Question

I am writing a decision tree class. In order to keep the design as flexible as possible I want to get the decision trees data using a custom "TableDataGetter" interface, which contains the method getData():String[*]. In my particular implementation, I want to use a class "TextTableDataGetter" which implements "TableDataGetter".

If my understanding is correct, the way to display with in UML Class diagrams is to use the composition relation between my decision tree class and the "TableDataGetter" interface.

My question is if, on the time of drawing the diagram, I want to specify I want to use the "TextTableDataGetter", how do I write this in standard UML?

I want to be as specific as possible on my diagram since I am having the UML software generate the code for me, as I brainstorm. I want to be sure, that in the decision tree class I have my dataGetter variable declared as "TableDataGetter dataGetter = new TextTableDataGetter()"

Answer 1

I answered a similar question here , same answer below.

Both aggregation and composition represent "has a" relationships. The difference between the two is that composition refers to exclusive ownership. For instance, a transaction "has a" transaction ID number, and that transaction is the only transaction that has that transaction ID number, the ID number is exclusive to the transaction. A transaction also "has a" transaction date, but many transaction might also have that same transaction date. Since the transaction date can be shared among multiple transactions it is not exclusive .

When you are drawing these two relationship types on a UML class diagram a composition relationship would be represented with a filled in diamond where a aggregation relationship would be represented by a diamond which is not filled in.

The book Introduction to Java Programming covers this subject in great detail.