Combining the Power of Meta-Programming and Meta-Modeling within the OMG MDA Framework.

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1 Combining the Power of Meta-Programming and Meta-Modeling within the OMG MDA Framework. Jean Bézivin & Nicolas Ploquin Université de Nantes - CRGNA Faculté des Sciences et Techniques 2, rue de la Houssinière BP Nantes cedex 3, France Jean.Bezivin@sciences.univ-nantes.fr 2 nd Workshop on UML for Enterprise Applications: Model Driven Solutions for the Enterprise

2 Outline Why the MDA? Rapid paradigm shift from objects to models Basic concepts of the MDA Revisiting the 4-layer architecture Tooling the MDA A tour of models and tools Model extraction Static MX JIT/MP Conclusion

3 Why the MDA? Objects failed to bring conceptual simplicity Platform migration is too frequent and too costly New models are emerging Models for humans and models for computers The unique (object) model is replaced by the multiple model Consequence : The middle-war is over

4 The middleware war is over COM+ DCOM CORBA IIOP XML SOAP HTTP HTML Sun's Java EJB Microsoft C# & DotNet Sun's reaction to C# & DotNet? + the Next Wonderful Middleware Platform (~2005) There is no clear winner nor loser The next battlefield will be model transformation The OMG's Model Driven Architecture (MDA) initiative is aimed at using modelling and metamodelling to drive the design and implementation of distributed systems.

5 New models are emerging From object to components and then to: Rules, Workflow, Services,

6 Consequence: having to deal simultaneously with several models of different semantics UML model Java model

7 From contemplative to productive Person -personid : unsigned long -surname : CString -givenname : CString -middleinitial : char -streetaddress : CString -postcode : CString -countryname : CString - address : CString +Person() +PersonInfo() Applicant class Employee -jobtype : CString -roomnr : unsigned long -department : CString -division : CString -jobtitle : CString -manager : unsigned long -headsdept : CString -headsdivision : CString -mobilenr : CString -birthdate : unsigned long +Employee() +GetCurrentAge() +EmployeeInfo() CourseSession -coursesessionid : unsigned long -coursedate : unsigned long -teaches -courseid : unsigned long -courselocation : CString +CourseSession() -is taught by 0..* +CourseSessionInfo() 1 1 -is in 0..* -is filled by sequence -companyname : CString -experience : CString -is made by -makes -reference1 : CString -reference2 : CString -reference3 : CString 1 0..* +Applicant() +ApplicantInfo() RegistrationForm +MakeApplication() 1 -is made * by a-uses +registrationform() * 1 -is taken by 1..* -made a Application PermittedStatusChange -productnr : unsigned long -allows change in -has a -fromstatus : char -certificationlevel : unsigned long -tostatus : char -applicationdate : unsigned long 0..* +PermittedStatusChange() +Application() 1..* +StatusChangeInfo() +ApplicationInfo() CourseRegistration -registrationdate : unsigned long -completionflag : bool -confirmeddate : unsigned long +CourseRegistration() +CourseRegistrationInfo() 0..* -takes Test -testscore : unsigned long +Test() +TestInfo() 0..* -gives Java code 0..* -applies to a RegForm ApplicantList PersonList Applicant Application ApplicationList 1 -is achieved findapplicant() findperson() 1 -is for a AppStatus -statuscode : char -statusname : CString +AppStatus() +AppStatusInfo() Exam -examid : unsigned long -uses -certificationlevel : unsigned long +Exam() 1 +ExamInfo() ExamSession -is used in -examsession : unsigned long -examlocation : CString -examdate : unsigned long 0..* +ExamSession() +ExamSessionInfo() Applicant() MakeApplication() Application() addapplication() addperson() From human-readable to computer-understandable (XMI)

8 Basic concepts of the MDA Revisiting the 4-layer organization Abstract Syntax Systems Compared Technology #1 Technology #2 (formal grammars (MOF + OCL) attribute grammars, etc.) Technology #3 (XML Meta-Language) Technology #4 (Ontology engineering) Technologies evaluation grid M 3 EBNF MOF A XML DTD Or Schema Upper Level Ontologies Different problems Different technological families M 2 M 1 Pascal Language Grammar A specific Pascal Program A specific execution of a Pascal program The UML meta-model A Specific phenomenon corresponding to a UML Model A XML document A XML DTD or Schema KIF Theories Abstract syntax systems Meta-models XML Ontologies +Description A Specific A XML modularity Logics UML Model document transformation +Conceptual rendering +Xpath, XSLT executability Graphs verification +RDF, OIL, DAML +etc. navigation +etc. [XMI=MOF+XML+OCL] etc. Model serialisation :from contemplative 2nd Workshop on UML for Enterprise to productive. Applications: Model Driven Solutions for the Enterprise Data bases

9 Systems and models M 1 (the modeling space) M 0 (the world) M isrepresentedby S A model M is a simplified representation of the world, as a matter of fact of only a part S of the world called the system.

10 Limited Substituability Principle The purpose of a model is always to be able to answer some questions in place of the system, exactly in the same way the system itself would have answered similar questions. System represents Model ask() ask()

11 The global MDA model space The development software cycle is populated with models Models are of unequal importance The model space is structured Models are linked in a complex organization network The content of each model is defined (constrained) by a corresponding meta-model (ontology) The model space is constantly broadening starting from the essential models (Domain, Service, Resource) Many different kinds of models Business models and computer models Models of product & models of processes Object, component, rule, workflow, service models among others Legacy (Cobol, RDB) and NT (Web, SOAP, etc) models PSMs, PIMs, PDMs, etc.

12 Various kinds of models Products and processes Legacy and components Static and dynamic etc. System represents Model ask() ask() Dynamic System StaticSystem Dynamic Model StaticModel

13 What is a Meta-Model? System represents Model S Meta-Model terminology assertions M M* The correspondence between a model and a system is defined by a meta-model.

14 The 3+1 Layers Level M 3 the MOF MMM Level M 2 the UPM MM (SPEM) the UML MM the CWM MM Level M 1 a UML model m another UML model m Level M 0 a particular use of m another use of m (This is not a modeling layer, it is the real world.)

15 Local and global definitions meta Node M 3 meta meta Link meta meta M 2 StkInstance instanceof StkClass meta meta M 1 acat instanceof Cat

16 MOF Global organization META NODE : NODE M3 Smalltalk Meta-model META META META NODE : MetaClass NODE : Class NODE : Instance META META META M2 Smalltalk model Real world MetaClass : Person class instanceof Class : Person instanceof Instance : Mary Mary, the real Stk object in a given computer, at a given addredd, unique in time and space. representedby M1 M0

17 Meta-programming vs. Meta-modeling M 3 MM meta MOF::Class MP meta meta meta M 2 STK::MetaClass STK::Class STK::Instance STK::Iof M 1 STK::Iof meta meta meta Metaclass class STK::Iof Metaclass STK::Iof Cat class STK::Iof Cat STK::Iof Felix STK::Iof

18 Tooling the MDA : Sample Adaptive's Framework France-Telecom Universalis Codagen Gen-it Codigo CodigoXpress DSTC dmof Interactive Objects ArcStyler Kabira Business Accelerator Kennedy Carter iuml and iccg Metamatrix MetaBase NetBeans Meta Data Repository MDR ONTOS ObjectSpark ObjectRad Java Metadata Server ObjeXion Software Netsilon Project Technology BridgePoint/DesignPoint Secant Technologies ModelMethods Soft-Maint Scriptor & Semantor Tata Research Development ADEX University of Berne MOOSE and much more

19 Example : The Y cycle PIMs (Platform Independent Models) Merging/binding phase M PSMs (Platform Specific Models) PDMs (Platform Description Models)

20 What is a pure "MDA tool"? It implements some operations on models or meta-models It is compliant with the main MDA recommandations (UML, MOF, XMI, etc.) It is interoperable with other MDA tools It is compatible with the MDA vision (meta-model driven) Operations on M. & MM. M. checking M. transformation M. merging M. presentation M. & MM. browsing Code generation Reverse engineering MM. Alignment

21 Source code model extraction This is a static system. a MOF meta-model This is a static model of a static system XMI a Cobol program Syntax analyser (lex, yacc, etc.) XMI a Cobol model Meta-model driven SC (source code) model extraction

22 Example :Semantor Explorer Full Syntax Source Code Model Extraction (once extracted, models can be worked on)

23 Round-Trip Engineering Forward engineering UML model Java Program Reverse engineering

24 MM-driven SC model extraction What kind of MM for source model extraction? Full syntax 100% of the info extracted Operation is reversible Partial syntax Non reversible operation Semantic Need some heuristics Examples Process classes Exception classes Interface classes Business classes Important (and obvious) remark: Class instances only exist at run-time (usual instances, processes, exceptions, etc.)

25 Part of the C# MetaModel (grammar) Member name : String members 0..* Assembly name : String 0..1 container TypedAttribute Field 0..* type 1 Property isreadable : Boolean iswritable : Boolean parameters 0..* Parameter isin : Boolean isout : Boolean name : String position : Integer 0..* 1 method Constructor MethodBase visibility : String isabstract : Boolean isfinal : Boolean isstatic : Boolean Method 0..* returntype 0..1 Type owner 0..1 qualifiedname : String isabstract : Boolean visibility : String issealed : Boolean namespace : String type 1 type 0..* content 0..* 0..1 super

26 JIT/MP : a new concept Just In Time Model Production An execution of a program dynamically produces an (XMI) model of its current situation on demand, Periodically, on given events (internal or externals), The produced model corresponds to an (XMI) MM that has been directly read by the program Produced models may be concurrently used and combined The nature of the produced models may change in time (MMdriven)

27 Combining the power of metamodeling and meta-programming This is a dynamic model. Introspection at work a C# meta-model a C# program execution read XMI write XMI sem [This may be the basic strategy for modern software maintenance] a C# model

28 Challenge How to associate instructions to different elements of the meta-model that will specify how the model may be extracted Hint : these instructions are C# code that uses the introspection API of C# This allows defining complex heuristics (e.g. finding patterns, etc.)

29 Interesting question a C# source program MM-driven model extraction a model? a C# program execution JIT model production a model

30 Several migration paths Meta-Model Driven software maintenance and evolution sytem (UML, MOF, XMI, etc.) MS/JUMP C# Cobol ADA Java Smalltalk Eiffel C# etc. etc. Java Eiffel?

31 Conclusions Meta-modeling and meta-programming are two orthogonal solutions They may be combined JIT/MP is a very powerful technique with tremendous protential