Do deliver **this** consequently

I can not use a (as I think it is inrtended, isn't it?):

crudClient.create() .setSid(this.sessionID) .setProjectId(this.projectID) .setObject(tgObject) .setTextgridUri(this.getTextgridURI()) .execute();

because getTextGridURI returns a CrudOperation, not a CreateOperation.

CrudOperation doens't have an execute() method!

To fix this:

• use CrudOperations interface?
• use CrudOperations as abstract class?
• implement setters in every single CrudOperation extension method (as CreateOperation)?