Transformation

The FRaMED editor works with a separate model. This ensures the simplicity of the original CROM-Model. Moreover, it provides developers with more flexibility and freedom.

To close the gap between the two models of FRaMED and CROM, a model-to-model transformation is implemented. This is done by using the Epsilon Transformation Language.

Transformation process

This part will contain some architecture documentation about the the transformation and its working process.

Assumptions and Prerequisites

The transformation requires some labels, i.e., NamedElements, to follow specific syntactic rules. This is necessary in order to be able to parse the given strings accordingly to their meaning in the graphical model. The assumed syntax is briefly defined in the following (using an EBNF-like notation).

  Operation := <name> "(" {Parameter} ")" ":" <type> 

  Attribute := <name> ":" <type> 

  Parameter := Attribute 

  Cardinality := (<integer> | "*") [".." (<integer> | "*")] 

  RoleGroupName := <name> "[" <Cardinality> "]"

Additional white spaces are ignored. <name> and <type> both stand for valid Java identifiers. The graphical front-end is responsible for assuring the correct format.

Transformation Table

Rigid Types

Graphical Element	Transformation
	A Shape with type NATURAL_TYPE, which contains an EString for the type's name, a segment (first segment) containing zero or more NamedElements as attributes, a segment (second segment) containing zero or more NamedElements as operations.
	A NaturalType with respective name, attributes, and operations.
	A Shape with type COMPARTMENT_TYPE, which contains an EString for the type's name, a segment (first segment) containing zero or more NamedElements as attributes, a segment (second segment) containing zero or more NamedElements as operations, a reference to a child model. The child model can contain parts with roles, relationships, and constraints.
	A CompartmentType with respective name, attributes, operations, and child reference.
	A Shape with type DATA_TYPE, which contains an EString for the type's name, a segment (first segment) containing zero or more NamedElements as attributes, a segment (second segment) containing zero or more NamedElements as operations.
	A DataType with respective name, attributes, and operations.

Groups

Graphical Element	Transformation
	A Shape with type GROUP, which contains an EString for the group's name, a reference to a child model, which can contain arbitrary model elements.
	A Group with respective name, and a correctly transformed child model. The child model's elements are contained in the group.

Roles, Role Constraints & Fulfillment

Graphical Element	Transformation
	A Shape with type ROLE_TYPE, which contains an EString for the type's name, a segment (first segment) containing zero or more NamedElements as attributes, a segment (second segment) containing zero or more NamedElements as operations, a NamedElement (description) for the occurence constraints of the role.
	A RoleType with respective name, attributes, and operations.
	A Shape with type ROLE_GROUP, which contains an EString for the group's name which can contain a cardinality specification for the role group, a NameElement (description) for the occurence constraints of the role group. a reference to a child model, which contains roles.
	Transformed to a RoleGroup with respective name (without cardinality), and a correctly transformed child model. The child model's elements are contained in the group.
[[img/transformation/role_prohibition.png]] [[img/transformation/role_equivalence.png]] </td> <td> A <code>Relation</code> with one of the following types: <ul> <li><code>RoleImplication</code></li> <li><code>RoleProhibition</code></li> <li><code>RoleEquivalence</code></li> </ul> The role constraint references to a source and target role. </td>
	Transformed to the respective role contraint, i.e., RoleInheritance, RoleProhibition, or RoleEquivalence. The referenced roles are stored in first (source) and second (target).
	A Relation of type FULFILLMENT. The relation contains a reference to a source shape (has to be a rigid type), and a list of referenced roles.
	Transformed to a list of Fulfillments, where for each referenced role a new fulfillment object with source as filler and the respective role as filled attribute.

Relations and Relationships

Graphical Element	Transformation
	A Relation of type INHERITANCE. The inheritance relation connects two elements of the same type, i.e., it is one of the following: DataInheritance between data types NaturalInheritance between natural types CompartmentInheritance between compartment types RoleInheritance between role types
	The corresponding, specific inheritance type with super and sub references. Furthermore, the relation is added to the outgoing relations of the source, and to the incoming relations of the target type.
	A Relation of type RELATIONSHIP, with a name, source and target elements, source and target label, specifying the cardinalities, referenced relation constraints which further describe the type of the relationship.
	The corresponding Relationship with correct name. The connected role types are referenced via Places, which also hold the cardinalities. A reference to the transformed relationship is added to each constraint.

Relationship Constraints

Graphical Element	Transformation
	A Relation with one of five types: TOTAL, CYCLIC, ACYCLIC, REFLEXIVE or IRREFLEXIVE.
	Transformed to Total, Cyclic, Acyclic, Reflexive or Irreflexive intra-relationship contraint, respectively. The reference to the relation it constraints is set in the transformation of the relationship itself.
	A Relation of type RELATIONSHIP_IMPLICATION. The implication has a source and target relationship.
	Transformed to RelationshipImplication inter-relationship constraint. The relationship references first and second are set to source and target, respectively.
	A Relation of type RELATIONSHIP_EXCLUSION. The implication has a source and target relationship.
	Transformed to RelationshipExclusion inter-relationship constraint. The relationship references first and second are set to source and target, respectively.

Testing

To ensure variety in all of our tests without setting up separate models by hand in every one we implemented a parameterized test which loads test cases out of the testcases directory inside the org.framed.transformation.test plug-in. To serialize those test cases a little emf model was build which consists of the TestCase case with the following attributes:

• title
• description
• framed model (Which will be transformed)
• crom model (the expected one which is used for comparing purposes)

So we just need to create a new file by using the default EMF-Editor implementation or FRaMED itself (for the framed model) to provide new tests.

Test generator

For cover all possibilities for (n)-relationships and therefor the combinations of all constraints per relationship, we create a test generator. It is written in python and needs to be called through cmd/terminal. Its output is a new folder with all possible testcases.