Handle external classes with graph

[iils-mriestenpattgenrichter]

How is a recommend way to handle external classes in a design language?
For example, data should be written to a file and the file should be accessed in different rules.

Can the file be added as attribute to a class and an instance can be asked for the attribute?

[iils-mriestenpattgenrichter]

Yes, external classes can be added as types of attributes. Therefore, instanced attributes can be stored in the graph and accessed via a graph query.
Adding an external class as type is achieved by wrapping the external class in a package (class diagram).
`type File wraps java.io.File

class ClassWithFileAttribute {
file : File
}`
See also the documentation (Language -> Classes Specification -> Datatype).

In the described example, it is a recommend way to handle the external class, but other problems may need other solutions.