A (Very) Short Introduction to Model-Driven Development (MDD)

Transcription

1 A (Very) Short Introduction to Model-Driven Development (MDD) (MDD ~ Model-Driven Engineering (MDE)) Introduction to MDD by Jan Pettersen Nytun, UiA, page 1, 4-Aug-11

2 Content Some background info What is a model? Types of modellers UML and MDD (MDA) Modelling Maturity levels Introduction to MDD by Jan Pettersen Nytun, UiA, page 2, 4-Aug-11

3 Introduction to MDD by Jan Pettersen Nytun, UiA, page 3, 4-Aug-11

4 From Wikipedia, the free encyclopedia on MDE: on the use of software modeling as a primary form of expression... With the introduction of UML, MDE has become very popular today with a wide body of practitioners and supporting tools... Introduction to MDD by Jan Pettersen Nytun, UiA, page 4, 4-Aug-11

5 Copied From: Model-Driven Semantic Web Engineering Dragan Gašević and Gerd Wagner Introduction to MDD by Jan Pettersen Nytun, UiA, page 5, 4-Aug-11

6 Copied from: Educating in MDE by Jordi Cabot

7 Copied from: Model-Driven Software Engineering in Practice Marco Brambilla, Jordi Cabot, Manuel Wimmer

8 Copied from: Model-Driven Software Engineering in Practice Marco Brambilla, Jordi Cabot, Manuel Wimmer

9 Content Some background info What is a model? Types of modellers UML and MDD (MDA) Modelling Maturity levels Introduction to MDD by Jan Pettersen Nytun, UiA, page 9, 4-Aug-11

10 Features of a Model A model according to Stachowiak exhibits the following features: Mapping feature A model is based on an original (there is a subject). Reduction feature A model only reflects a (relevant) selection of an original's properties. Pragmatic feature A model needs to be usable (in place of an original) with respect to some purpose. Introduction to MDD by Jan Pettersen Nytun, UiA, page 10, 4-Aug-11

11 [1]: all meaning is mapping-mediated, which is to say, all meaning comes from analogies. Math terms: A homomorphism is a structure-preserving map from one structure to another. structure X structure Y A B C E D model subject (what is being modelled)

12 I would say: All meaning comes from analogies and composition. + =

13 Most models found in software engineering are specification models (prescriptive models) and typically the "original" does not exist when the model is created. Doing reverse engineering is like making a descriptive model (descriptive models are the most common models in natural science). Introduction to MDD by Jan Pettersen Nytun, UiA, page 13, 4-Aug-11

14 Specification Models Guides us in constructing a system. The model is like a blueprint high complexity requires good modelling techniques. Models may help us visualize a system at different levels of abstraction, this makes it easier to manage complexity and to understand the system. Introduction to MDD by Jan Pettersen Nytun, UiA, page 14, 4-Aug-11

15 Why Modelling? High level of abstraction gives cheaper experiments (checking multiple solutions). Models document decisions. Models help communication between different stakeholders. Introduction to MDD by Jan Pettersen Nytun, UiA, page 15, 4-Aug-11

16 Content Some background info What is a model? Types of modellers UML and MDD (MDA) Modelling Maturity levels Introduction to MDD by Jan Pettersen Nytun, UiA, page 16, 4-Aug-11

17 From: Model-driven development: The good, the bad, and the ugly [1] the MDD community can be divided into three parts sketchers... blueprinters, and model programmers. Introduction to MDD by Jan Pettersen Nytun, UiA, page 17, 4-Aug-11

18 [1] The Sketchers use UML to facilitate the understanding of code use the sketches to help communicate ideas and alternatives about what you are about to do. You do not show every class, just those that are interesting Introduction to MDD by Jan Pettersen Nytun, UiA, page 18, 4-Aug-11

19 [1] The Blueprinters... create very detailed design models, handed off to coders to produce implementations... Sketchers and the blueprinters maintain a strong distinction between design models and code artefacts. Introduction to MDD by Jan Pettersen Nytun, UiA, page 19, 4-Aug-11

20 [1] The model programmers support the use of UML (or other notation) as a development language with executable semantics (e.g., action semantics or statecharts). The distinction between models and code is obscured Introduction to MDD by Jan Pettersen Nytun, UiA, page 20, 4-Aug-11

21 Approaches to MDD Generative Approach to MDD Models are often used for code generation, followed by compilation and then execution. It keeps modelling and execution separate. Interpretative Approach to MDD Allows models to be directly executed (it relates to the interpretative programming language approach). Introduction to MDD by Jan Pettersen Nytun, UiA, page 21, 4-Aug-11

22 Content Some background info What is a model? Types of modellers UML and MDD (MDA) Modelling Maturity levels Introduction to MDD by Jan Pettersen Nytun, UiA, page 22, 4-Aug-11

23 UML 1.3 Is Not a Visual Programming Language? UML 1.3 is a visual modeling language. It does not have all necessary visual and semantic support to replace programming languages. But the introduction of Action Semantics into UML has changed this! Not all agrees State Charts already existed and could be used instead of Action Semantics. Introduction to MDD by Jan Pettersen Nytun, UiA, page 23, 4-Aug-11

24 Executable UML Abstracting away programming languages. Class diagrams shows structure. Statechart diagrams shows object lifecycle (control). Action language shows behavior (algorithm) Introduction to MDD by Jan Pettersen Nytun, UiA, page 24, 4-Aug-11

25 Refinement [1]: A relationship that represent a fuller specification of something that has already been specified at a certain level of detail or at a different semantic level. Refinement Realization Chain conceptual towards a specific platform implementation running. impl. «refine» «refine» PIM PIM/PSM PSM «refine» Implementation Source Code «compile» Implementation Target Code «load» Loaded Impl. Target Code The elements of the realization chain can be seen as models that in some way can be interpreted lets call them Programs, even if some elements only model structure (as opposed to behavior). Interpretation of Program PSM m PIM PSM 1 PSM m Runtime Instances Runtime Instances VirtualMachine Processor

26 Model-Driven Architecture (MDA) A software design approach for the development of software systems... a set of guidelines for the structuring of specifications, which are expressed as models. It was launched by the Object Management Group (OMG) in Introduction to MDD by Jan Pettersen Nytun, UiA, page 26, 4-Aug-11

27 [2]: The MDA Process [3]: separates specification of functionality from specification of implementation of that functionality on a specific platform.. PSM Bridge Code Bridge [4]: First, you build a model with a high level of abstraction independent of any implementation technology. This is called a Platform Independent Model (PIM). Next, the PIM is transformed into one or more Platform Specific Models (PSMs). A PSM is tailored to specify your system in terms of the implementation constructs that are available in one specific implementation technology, e.g. a database model, an EJB model. The final step is to transform a PSM to code. Because a PSM fits its technology very closely, this transformation is rather trivial. The complex step is the one in which a PIM is transformed to a PSM. Introduction to MDD by Jan Pettersen Nytun, UiA, page 27, 4-Aug-11

28 MDA Example 1 Several Application PIM Reverse engineer First transformation Platform Independent Model PSM CORBA Model EJB Model XML/SOAP Model Other Models Second transformation Implementation CORBA Code EJB Code XML/SOAP Code Other Code Introduction to MDD by Jan Pettersen Nytun, UiA, page 28, 4-Aug-11

29 MDA Example 2 Three Tier Solution One Application PIM PSM Relational DB PSM EJB Comp. PSM Web PSM SQL Code PSM EJB Code PSM JSP Code Introduction to MDD by Jan Pettersen Nytun, UiA, page 29, 4-Aug-11

30 Content Some background info What is a model? Types of modellers UML and MDD (MDA) Modelling Maturity levels Introduction to MDD by Jan Pettersen Nytun, UiA, page 30, 4-Aug-11

31 Model-based Engineering The use of model in software development requirements Requirement analysis design implementation verification deployment Development Testing Jos B. Warmer and Anneke Kleppe defined Modeling Maturity levels (MML) MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only Validation 31 Selo Sulistyo created this slide

32 Model-based Engineering MML 0 requirements MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only Requirement analysis design implementation Development No specification My software verification Testing deployment Validation 32 Selo Sulistyo created this slide

33 Model-based Engineering MML 1 requirements MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only Requirement analysis design Development Specification of software is written down in one or more natural language documents. implementation verification deployment Testing Validation 33 Selo Sulistyo created this slide

34 Model-based Engineering MML 2 MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only requirements Requirement analysis Specification of software in one or more natural language documents plus several high-level diagrams to explain the overall architecture. design Development implementation verification deployment Testing + Validation 34 Selo Sulistyo created this slide

35 Model-based Engineering MML 3 MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only requirements Requirement analysis Specification of software is written down in one or more models. Additional natural language text is used to explain the background and motivation of the models. design Development implementation + verification deployment Testing Validation 35 Selo Sulistyo created this slide

36 Model-based Engineering MML 4 MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only requirements Requirement analysis design Development Specification of software is written down in one or more models. Natural language text is used to explain the background and motivation of the models. implementation verification deployment Testing The models are precise enough to have a direct link with the actual code. Validation 36 Selo Sulistyo created this slide

37 Model-based Engineering MML 5 MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only requirements Requirement analysis design implementation Developm ent The models are precise and detailed enough to allow complete code-generation. The code is invisible (as assembler is today). Modeling language High level programming language. verification deployment Testing Validation 37 Selo Sulistyo created this slide

38 Model-based Engineering Modeling Maturity Levels (MML) MML 0: No Specification MML 1: Textual Specification MML 2: Text with Models MML 3: Models with Text MML 4: Precise Models MML 5: Models only MBE! 38 Selo Sulistyo created this slide

39 In theory, there is no difference between theory and practice. But in practice, there is (Jan L. A. van de Snepscheut/Yogi Berra)

40 References [1] [2] Introduction to OMG's Unified Modeling Language (UML ) [accessed Aug. 2002] [3] OMG Editor: Model Driven Architecture (MDA) (ormsc/ ) Accessed 19 August 2002 [4] Addison-Wesley, MDA Explained: The Model Driven Architecture : Practice and Promise Anneke Kleppe, Jos Warmer, Wim Bast (Klasse Objecten, Soest, the Netherlands [1] Douglas Hofstadter. I Am a Strange Loop (ISBN ) (2007) Introduction to MDD by Jan Pettersen Nytun, UiA, page 40, 4-Aug-11