A Model-based Development approach for Model Transformations

Shekoufeh Kolahdouz Rahimi, Kevin LanoShekoufeh.kolahdouzrahimi@kcl.ac.uk, kevin.lano@kcl.ac.uk

Model Transformation Issues• Specification of model

transformations

• Development processes for model transformations

• UML-RSDS: A General Model-Driven Software Development Approach

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Development Process for Model Transformations

• Requirements

• Abstract Specification

• Explicit Specification and Design

• Implementation

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Tree to Graph Transformation

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Transformation

Requirements

check validity of the source model(no

duplicate names, and no undefined parent trees)

• carry out the mapping upon a valid model Asm1:

Asm2:

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• property of the tree metamodel

• properties of the graph metamodel

Ens1:

Ens1:

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Pres is a predicate in OCL over the source metamodelEns is a predicate in OCL over the target metamodelAsm may in general be a predicate over both metamodels

Abstract specification

C1 : For each tree node in the source model there is a graph

node

in the target model with the same name

C2 : For each non-trivial parent relationship in the source

model,

there is an edge representing the relationship in the target

model

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C3 For each graph node in the target model there is a tree

node

in the source model with the same name

C4 For each edge in the target model, there is a non-trivial parent

relationship in the source model, which the edge represents

C5 The same as Ens2

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C3 and C4 are duals of C1 and C2C1 and C3 together with the metamodels ensure that there is a 1-1 mapping from trees to nodes, which facilitates change propagation in both directions.

Cons should be sufficient to establish Ens:

Cons should prove that Pres are preserved, via a suitable interpretation from the source language to the target language

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Explicit specification and design

Phase1 : Map all tree elements to corresponding nodes

Its global specification is C1 and C3, its assumption is Asm

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for t : Tree do mapTreeToNode(t)

Phase2: Map parent links to corresponding edges.

the global specification C2 and C4 and C5, its assumption is C1

and C3 and

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for t : Tree do mapTreeToEdge(t)

A ruleset in UML-RSDS is a set of rules (operations), it is defined as a UML class with a behaviour defined by an activity. This controls the allowed order of application of the rules. In this example we can therefore have one ruleset for each phase, each with a single operation.

By composing the two phases in sequence, we can also establish the overall correctness of the transformation:

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Implementation

In this case a direct change-propagating implementation of Cons is possible, or Java code can be generated from the explicit activities and rules.

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Case Study 2: Mapping activities from UML 1.4 to UML 2.2

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Phase1: Establishes the correspondences between each kind of

state vertex and activity node, ie, the axioms F1 to F11 and their inverses.

Phase2: Establishes the correspondences of guards and

transitions with opaque expressions and activity edges, assuming the correspondences of states from phase1.

Phase3: Establishes the correspondences of partitions and

activity graphs with activity partitions and activities, assuming the correspondences of states from phase1 and transitions from phase2.

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The overall algorithm is specified as the composition of the three

phases: activity1; activity2; activity3.

Case Study 3: UML to Relational Database mapping

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phase1: replace each association class by two new

associations.

This establishes AssociationClass = {}.

phase2: remove multiple and single inheritance, either by

replacing a generalisation by a 0..1 to 1 association, or by merging a class and its superclass(es). This establishes Generalization = {}.

phase3: Introduce a primary key for each class.

phase4: Replace many-many associations with a new class and

foreign keys, replace 1-many associations by foreign keys. This establishes

Association = {}.

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Transformation algorithm

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Questions?

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