Error while defining a EEList Type attribute in EMF

Question

In Eclipse, I'm trying to add a List to my EMF Model. In .ecore model:

• I add a new class "MyClass" to my model in EMF
• then add an attribute "MyList" to this class, set the EType of this attribute as EEList<>
• then set the dataType of the list element to EString.

But when i try to open the genmodel of this model, appears an error saying: "The attribute 'MyClass.MyList' is not transient so it must have a data type that is serializable".

What am i doing wrong?

Thanks in advance.

Answer 1

You do not have to 'manually' deal with it being a list. Remember, you are using UML. A List is merely an ordered association to a type, in which the upper bound is set to *. Therefore, simply add MyList to MyClass, set its multiplicity to 0..-1 (by setting its upper bound to -1, which means * in EMF) and ensure the association's Ordered property is set to True (otherwise you would get a Set). Also set its type to EString.

Here is an example, in which a DFA has a list of the type State, in accordance with the above instructions. I also set "containment" to true, as to make the list hold a strong reference the objects it contains (this has to do with memory management, I would suggest you to do the same). Note that I've set the type to State, as this is a list of State objects.