Formalizing model transformation patterns

Abstract

Model transformation has become an established field, and it is important to improve the quality of specifications written in transformation languages. Different transformation patterns have been introduced in the model-driven engineering (MDE) community to improve the quality of transformation specifications. However, due to the different definitions of pattern concepts by different authors, it is difficult for practitioners to understand how to apply patterns in practice. Therefore, there is a need to unify transformation pattern concepts by presenting a generic metamodel and formalizing patterns in terms of this metamodel, to define the meaning of pattern application. In this research a general metamodel for definition of different design patterns in model transformation is provided. The metamodel presents clear description of common aspects of transformation patterns, which facilitates the application of patterns on model transformations by validating the application against the underlying formalism. Additionally, a unified and precise terminology for the application and verification of model transformation patterns by using a formal model of model transformation patterns in the Z notation is presented. To show the applicability of the proposed formalism, four well-known model transformation patterns are specified. K E Y W O R D S model-driven development (MDD), model transformation, design pattern, formal model 1 | INTRODUCTION Model transformations (MTs) have become more and more complex in recent years, as a result of their application to substantial problem cases in both academia and industry. Enhancing the quality of model transformations to provide a result in an efficient and modular way is a crucial task for the model-driven community. Design patterns for model transformations have been identified as an important solution to potentially improve the quality of model transformations. 1-3To obtain the benefit and utilize the productivity accompanied by the pattern application in MDE, model transformation patterns must first be formalized, which paves the way for automating the MT-based software development and verification. [3][4][5] Exploring the literature reveals some formal models for model transformations. [6][7][8] However, to the best of our knowledge, there is not any formalism for model transformation patterns in the literature. Having a unified formalism regarding model transformation patterns will provide a foundation to support the pattern application and verification features easily in the current model transformation tools. 9,10 As a result, this research aims to present a new formalism for defining model transformation patterns and expressing the semantics of pattern application.To provide a conceptual view which serves as the informal basics of the proposed formalism of the MT patterns, an abstract architecture representing the underlying concepts such as model and metamodel is presented first. In this research, we use the Z specification language to formalize the MT design patterns. In a...

Towards a pattern‐based model transformation framework

“…Following this section, Section 4 (after a brief introduction to our MT pattern specification formalism and pattern specification catalog in our previous work 19 ) is dedicated to the specification of five other commonly used MT patterns including Phased Construction pattern , Section 4.1.1; Map Objects Before Links pattern , Section 4.1.2; Auxiliary Metamodel pattern , Section 4.1.3; Recursive Descent pattern from the Rule Modularization Category , Section 4.1.4; and Remove Duplicated Expression Evaluations pattern from the Rule Optimization Category , Section 4.2.1. According to Lano et al, 25 these are 5 of the most widely‐used transformation patterns in practice.…”

“…We specified four cases of well‐known model transformation patterns, that is, Entity Splitting, Entity Merging, Introduce Rule Inheritance, and Unique Instantiation patterns (immediate access from https://doi.org/10.5281/zenodo.7536661) in Rouhi et al 19 For consistency purposes, we continue using Z because the Z specifications give precise and explicit definitions of the patterns, in a formalism independent of any particular MT language. Z has been used for several decades and is considered one of the more readable and understandable formal languages 26 .…”

“…To verify our formal model, like our previously used approach, 19 here first we translate our model to Alloy 36 and then verify its applicability using the Alloy Analyzer 6.1.0, https://alloytools.org/. The translation process from the Z specification models to Alloy counterparts is straightforward.…”

“…One of the main requirements of an MT pattern application framework will be the precise specification of the MT pattern catalog. Since most of the MT patterns in the literature are described informally, 12,17,18 there is a need for a formalism for the precise specification of patterns 19 . In other words, the main obstacle to the development of most MT tools supporting MT pattern application is the lack of formal semantics regarding the precise specification and modeling of the underlying concepts 20,21 …”

“…The main contributions of this article are as follows: Extending our presented formalism 19 to specify other five well‐known MT patterns namely Phased Construction, Map Objects Before Links, Auxiliary Metamodel, Recursive Descent, and Remove Duplicate Expression Evaluation. Constructing a pattern‐based MT development framework based on formally‐specified patterns, with three steps including: Analyzing the given MT to measure its quality flaws, Examining quality flaw indicator thresholds, Recommending appropriate patterns to resolve the quality issues. Demonstrating the applicability of the proposed formalism in practice by detecting model transformation technical debts in example cases, and refactoring the transformations by applying appropriate patterns. …”