Web Technologies

Introduction to Model Driven Engineering

Piero Fraternalipiero.fraternali@polimi.it

Skype: pierofraternali

Models: a meeting place for developers & users

Motivations

• “Supply of talented IT staffers isn't keeping up with demand. And it won't change anytime soon.” – Eric Chabrow, in The

New IT Worker Shortage, CIOInsight 2009

#programmers

#applications

2005 2010 2015 2020

From crafting to fabrication

• Engineering addresses the optimization of production by means of abstraction and standardization

• Products are modeled, verified, and produced using standard models and methods

Models

• A model is an ABSTRACT REPRESENTATION of a product, service or system that allows us to investigate, verify, and document its properties BEFORE production

Software as an engineering product

• SW is an engineering product

• BUT:– It can be changed easily,

even after delivery and during usage

– It is produced in short time and at low cost

– It must satisfy a broad spectrum of requisities, hard to quantify

• SO engineering practices are not always applied

Software Models

• Software Engineering has a long tradition on the use of abstraction and software models

• MODEL DRIVEN ENGINEERING• SOFTWARE MODELS are

– An abstract representation of a system, independent of technology

– A tool for expressing and verifying requirements– A starting point for automatically generating the

code

History

• Software models are as old as software

• Flow diagrams were the first tool for describing software

• Programming language and models evolved together– Imperative programming –

flow diagrams– Info systems – ER– OO systems – object models

Milestones

P.- ChenThe Entity-Relationship Model-Toward a Unified View of DataTODS 1976

D. Harel, "Statecharts: A Visual Formalism for Complex Systems", (1987)

Outlook (by Gartner 2010)

• Key Findings in MDE– The complexity of new, service-oriented

architectures (SOAs) and business process management (BPM) demand more-abstracted, model-driven approaches.

– Business and IT modeling standards and technologies are converging.

– The differences between design time and runtime technologies are disappearing

Modeling convergence

Outlook (by Gartner 2010)

• Recommendations– Ensure collaboration among the IT organization,

business process architects and the analysts who are using these models;

– Use multiple methodologies and approaches to Application Development — especially those that leverage modeling efforts, agile methods, and reusable design patterns and frameworks to improve productivity, while ensuring quality and performance.

– Implement the role of application architect to promote reusable software and data services.

Economic Value (BPM)

MDA: The Modern Age of MDE

• Object Management Group (OMG) unified several modeling languages into a coherent proposal (MDA= Model Driven Architecture) setting the stage for a convergence of architecture, languages, notations, and tools

• UML is the most popular ingredient of MDA but not the only one

MDD, MDA, MDE

MODEL DRIVEN

ARCHITECTURE

MODEL DRIVEN DEVELOPMENT

MODEL DRIVEN ENGINEERING

MODEL DRIVEN TESTING

MODEL DRIVEN COST ESTIMATION

MODEL SEARCH

History

• 1989: OMG formed to create a standard for distributed object systems

• 1991: Corba 1.0 specification released• 1996: OMG includes modeling as a focus• 1997: UML adopted by OMG• 2001: OMG adopts MDA• 2005: UML 2.0 adopted by OMG• 2006: BPMN standard adopted by OMG• 2009: BPMN 2.0 beta 1

OMG MDA standards

• OMG Standards– Modeling – UML– Metamodeling – MOF– Action semantics– Model interchange – XMI– Human-usable textual notation – HUTN– Model-based testing and debugging– Domain-specific UML profiles

MDA core concepts

• System = the subject: a program, a single computer system, some combination of parts of different systems, a federation of systems, each under separate control, people, an enterprise, a federation of enterprises…

• Problem space (Domain): the context where the system operates

• Solution Space: the spectrum of possible solutions that satisfy the system requirements

• Model: a (partial or total, abstract or concrete) representation of the system and its environment

MDA core concepts

• Architecture = specification of the parts and connectors of the system and the rules for the interactions of the parts using the connectors

• Viewpoint: description of a system that focuses on particular concerns

• View: a model of a system under a specific viewpoint

• Transformation: the conversion of a model into another model

MDA core concepts

• Platform: set of subsystems and technologies that provide a coherent set of functionality through interfaces and specified usage patterns (e.g., JEE, .NET)

• Platform Model: a set of technical concepts, representing the different parts that make up a platform and the services provided by that platform

Development

• In MDA development is a chain of transformations from model to model, until enough “concreteness” is incorporated to make the model “executable”

How are models specified

• M0: a concrete system, your application

• M1: the model of your system

• M2: the concepts used to represent your models (e.g., UML or BPMN metamodels)

• M3: the formalism that dicates the rules for defining modeling languages (e.g., UML metamodel expressed in Meta Objet Format-MOF)

M3: meta-meta-model

M2: meta-model

M1: model

M0: system

describes

describes

describes

describes

Example

Customer_table Order_table

customer order

system

model

metamodel

Why meta-models

• Allow a syntactically precise definition of modeling languages

• Can be read by tools, enable portability, model parsing (syntactic) checking

• Like grammars for textual languages and ontologies for semantic languages

The WebML metamodel(fragment)

Classes of models (viewpoints)

• Computation Independent Models: represent the business view of the system

• Platform Independent Models: represents the system abstracting from technology

• Platform Specific Models: represents the system considering technology

CIM

PIM

PSM

mapping

mapping

CIM: examples

• Business Process Modeling Notation: – BPMN provides a

Business Process Diagram (BPD), which is a Diagram designed for use by the people who design and manage business processes.

PIM: examples• Production Rule Representation

(PRR)– a standard production rule

representation that is compatible with rule engine vendors' definitions of production rules

• Product Lifecycle Management Services (PLM)

– a PIM for Product Lifecycle Management Services derived from the ISO 10303-214 STEP model

• Gene Expression (GENE)– representation of gene expression data

and relevant annotations, as well as mechanisms for exchanging these data

• General Ledger (LEDG)– interfaces and their semantics to

enable interoperability between General Ledger systems and accounting applications

Model Transformations

• The application of mapping rules and knowledge to a source model to obtain a target model

• Can use different styles, based on how the mapping rules are specified

Source model

Target model

Additional information

DesignPatterns

Transformation

In this Course

• Business process

Modeling Notation

(BPMN 2.0)

• Web Modeling

Language (WebML)

• Java enterprise

Edition (JEE)

CIM

PIM

PSM

mapping

mapping

Domain Specific Languages (DSL)

• DSL: a language for describing systems in a specific domain (Web apps, embedded systems, etc)

• General Purpose Language: a language for describing systems in multiple domains (e.g., UML)

MDA and DSL

• MDA offers two standard ways to define DSLs

• Stereotyping: UML 2.0 elements are overloaded with domain specific meaning

• Metamodelling: new language constructs are defined

GPL vs DSL

• GPL– (Often) Standard– Portable across tools– More complex– Less intuitive to learn– Lack of precise semantics– Harder to use for code

generation

• DSL– Easier to learn for domain

experts– More precise semantics,

better checking– More amenable to

optimized code generation– Narrower scope– Non standard– Less portable across tools

GPL: UML

• A concrete syntax for specifying any kind of system

• Customizable with extension mechanism (family of languages: Real-Time UML, UML for EDOC..)

• Supported by tools

UML structure

UML INFRASTRUCTURE

MOF

PR

OF

ILES

OCL

ST

AT

E

MA

CH

INE

S

CLA

SS

ES

& C

OM

PO

NE

NT

S

AC

TIV

ITIE

S

INT

ER

AC

TIO

NS

AC

TIO

NS

FLO

WS

BASIC UML

Basic level

Intermediate level

Complete level

DSL: forms

DSL: examples

DSL Application Domain

BNF (1950! ) Syntax Specification

HTML Hypertext Web Pages

MATLAB Technical Computing

SQL Database Queries

LaTex Text processing

Marjan Mernik, University of Maribor

Jan Heering, CWI

Anthony M. Sloane, Macquarie University

ACM Computing Surveys, Vol 37, No. 4

Executability of DSL

• Well-defined execution semantics – HTML

• Input language of an application generator– WebML: Web/SOA modeling– Application generator compiles the DSL into a GPL (Java)– More declarative, well-defined execution semantics

(StateCharts)• Not executable but useful for application generation

– BNF: purely declarative, but can be an input language for a parser generator

• DSL not meant to be executable– Domain-specific data structure representations– Benefit from editors, analyzers, consistency checkers

Language levels (Caper Jones)

Language Level Relationship to Productivity

LANGUAGE LEVEL PRODUCTIVITY AVERAGE PER STAFF MONTH -------------------------- ------------------------------------------------------------------ 1 - 3 5 to 10 Function Points 4 - 8 10 to 20 Function Points 9 - 15 16 to 23 Function Points 16 - 23 15 to 30 Function Points 24 - 55 30 to 50 Function PointsAbove 55 40 to 100 Function Points EXCEL

MATHCAD

Visual DSLsDomain

IdeaFinishedProduct

So

lve

pro

ble

m in

dom

ain

term

sAssembler

Map to code, implement

UML ModelMap to UML

Generate,Add bodies

ComponentsDSVLModel

Generate callsto components

No map!

CodeMap to code, implement

Framework for Domain-Specific Visual LanguagesJuha-Pekka Tolvanen, Steven Kelly, Jeff Gray, Kalle Lyytinen

OOPSLA workshop on DSVL

Visual DLS design and implementation

DomainIdea

FinishedProduct

ComponentsDSVLModel

Generate callsto components

Easy!

Expert(few)

Normal(many)

Codegeneration

DSVLmetamodel

Componentlibrary

Meta CASE for DSVL design

Concepts Symbols

GeneratorsRules1 2 3 4

MDA and Tools

Metamodels

MODELS

Reverse engineering

Import & Export

Textual model Editor

Visual Model Editor

Model Checker

Teamwork

M2M M2text

OTHER MODELS

SOURCE CODE

Metamodel editors

References• Peter Pin-Shan Chen "The Entity-Relationship Model: Toward a Unified

View of Data" ACM on Database Systems, Vol. 1, No. 1, March 1976• Chen, Peter P., Entity-Relationship Modelling: Historical Events, Future

Trends, and Lessons Learned, Springer-Verlag New York, Inc, 2002, pp. 296-310

• D. Harel, "Statecharts: A Visual Formalism for Complex Systems", Sci. Comput. Programming 8 (1987), 231-274.

• J, Rambaugh, Object-Oriented Modeling and Design. With others. Prentice Hall, ISBN 0-13-629841-9, 1991

• G. Booch, Object-Oriented Analysis and Design with Applications. Benjamin Cummings, 1991 (2° Edition 1994, Addison Wesley)

• I. Jacobson, Object-Oriented Software Engineering: A Use Case Driven Approach (ACM Press) With Magnus Christerson, Patrik Jonsson & Gunnar Overgaard. Addison-Wesley, 1992, ISBN 0-201-54435-0, 1992

• I. Jacobson, Grady Booch & James Rumbaugh, The Unified Software Development Process. Addison-Wesley Professional, 1999, ISBN 0-201-57169-2, 1999

References

• Frankel. “Model Driven Architecture: Applying MDA to Enterprise Computing.” Wiley, 2003

• MDA Guide– www.omg.com/mda

• Marjan Mernik, Jan Heering, Anthony M. Sloane: When and how to develop domain-specific languages. ACM Comput. Surv. 37(4): 316-344 (2005)

• Jeff Gray, Kathleen Fisher, Charles Consel, Gabor Karsai, Marjan Mernik, Juha-Pekka Tolvanen: DSLs: the good, the bad, and the ugly. OOPSLA Companion 2008: 791-794

• Juha-Pekka Tolvanen, Steven Kelly, Jeff Gray, Kalle Lyytinen, Framework for Domain-Specific Visual Languages, OOPSLA WS on DSVL 2001

References

• Wynn, Moe T. and Verbeek, H.M.W. and van der Aalst, Wil M. and ter Hofstede, Arthur H.M. and Edmond, David (2007) Business Process Verification - Finally a Reality! Business Process Management Journal.

• Johan den Haan, Model Driven Engineering, http://www.theenterprisearchitect.eu/archive/2009/01/15/mde---model-driven-engineering----reference-guide

• Mike Blechar, David Norton , Trends in Model-Driven Development, 4Q09-3Q10, Gartner