1. OMG’s Model Driven Architecture
Davide Buscaldi
D.I.S.I.

2. Summary 1. Introduction 2. MDA Overview 3. Developing in MDA
4. MDA in the Practice
5. References

3. 1. Introduction

4. A heterogeneous world…
Programming languages: (see also: the DoD survey)
~3 million COBOL Programmers
~1.6 million VB Programmers
~1.1 million C/C++ Programmers
Operating systems:
Unix, MacOS, Windows(3.1->XP),PalmOS
Embedded devices
Networks:
Ethernet, IP, USB, FireWire
Bluetooth, b, HomeRF
Survey: indagine, studio

5. Where can we agree?
Hetereogenity hinders the development of enterprise distributed systems
There will not be consensus on
Hardware
Operating systems
Network protocols
Programming languages
We can agree at an higher level
Middleware

6. Middleware A software layer that masks hetereogeneity
Placed between operating systems and application components

7. Middleware proliferation
Middleware itself has proliferated:
CORBA
COM / DCOM / MTS
Java / EJB
XML / SOAP
C# / .NET
None of them prevails over the others
The problem remains

8. The Object Management Group (OMG)
An open membership and no-profit consortium
Produces and mantains computer industry specifications for interoperable enterprise applications
Who are OMG?

9. OMG’s Milestones 1989 1991 1996 MDA 1997 2001 OMG is founded CORBA 2.0
CORBA 1.0, IDL
MDA
1997
UML, MOF, XMI, CWM
2001

10. 2. MDA Overview

11. What is the MDA?
An approach to IT system specification that separates the specification of system functionality from the specification of the implementation of that functionality on a particular technology platform
“Design once, build it on any platform”
Java’s mantra: “write once, run anywhere”

12. Basic concepts of MDA
A model is a formal specification of the function, structure and/or behaviour of a system
Examples:
Source code is a model
An UML-based specification is a model
Models of different systems are structured explicitly into:
Platform Independent Models (PIM)
Platform Specific Models (PSM)
Spiegare meglio

13. Platform Independent Model (PIM)
A “formal” specification of the structure and function of a system that abstracts away technical detail
Expressed using UML
Realizzazione di un modello concettuale del sistema completamente indipendente dalla piattaforma

14. PIM: an example

15. Platform Specific Model (PSM)
Specifies how the functionality specified in a PIM is realized on a particular platform
Expressed using UML extended with platform specific UML profiles
Platform themselves also have a specification and an implementation
PSM is expressed in terms of the specification model of the target platform
Since UML is independent of middleware technologies, it is not obvious to the casual observer how to harness this power to express a PSM

16. PSM: an example

17. MDA metamodel UML PIM MOF PSM Metamodel PIM Mapping techniques
Infrastructure
<<depends on>>
<<independant of>>
PIM Mapping techniques
<<based on>>
1..n
UML
Mapping from PIM to PIM
1..n
<<expressed with>>
PIM
<<described with>>
1..n
Metamodel
MOF
<<expressed with>>
<<expressed with>>
<<described with>>
1..n
Mapping from PIM to PSM
1..n
Refactoring from PSM to PIM
<<based on>>
1..n
Other languages
PSM
PSM Mapping techniques
Mapping from PSM to PSM
1..n

18. MDA in a Snapshot Vertical Domains Core Technologies
Snapshot or Overview?
Ci dà un’idea di come i vari standard si inseriscono insieme
Pervasive Services
Core Target Platforms

19. 3. Developing in MDA

20. System Development Lifecycle and the MDA approach
PIM to PIM mappings
PSM to PSM mappings
UML MOF CWM
1 - UML MOF CWM used to describe PIMs
2 - PIM can be refined n-times with PIM to PIM mappings
3 -
Time
PIM to PSM mappings (projection on a specific platform)

21. Developing in MDA – Step 1: the PIM (1/2)
All MDA development projects start with the creation of a PIM
PIM at this level represents business functionality and behaviour, undistorted by technology details
MDA application-modeling tools contain representations of Pervasive Services and Domain Facilities allowing them to be used and/or incorporated in the application via a menu selection
PIM is built by business and modeling experts working together

22. Developing in MDA – Step 1: the PIM (2/2)
Pervasive Services Model
PIM
Calls
Domain Facilities Model
Calls

23. Developing in MDA – Step 2: the PSM (1/2)
Once the first iteration is complete, the PIM is input to the mapping step which will produce a PSM
Code is partially automatic and partially hand-written
PIM can be mapped either to a single platform or to multiple platforms

24. Developing in MDA – Step 2: the PSM (2/2)
PIM
Maps to
Maps to
Maps to
CORBA Model
Java/EJB Model …
Other Model

25. Developing in MDA – Step 3: Generating Application (1/2)
An MDA tool generates all or most of the implementation code for the deployment technology selected by the developer
Re-integration on new platforms can be done by reverse engineering the existing application into a model and redeploy

26. Developing in MDA – Step 3: Generating Application (2/2)
PIM
Maps to
Maps to
Maps to
CORBA Model
Java/EJB Model …
Other Model
Maps to
Maps to
Maps to …
CORBA
Java/EJB
Other

27. 4. MDA in the Practice

28. MDA Adoption Status Adoption of MDA is at an early stage
UML profiles underway:
CORBA (adopted)
EJB (adopted)
SOAP/XML (in process)
.NET (to be started)
UML 2.0 in process
Verificare e mettere date

29. Future Trends
“A market for MDA will be created as OO modeling and development tool vendors incorporate MDA into their offerings”
“It will be two or three years before mature MDA tools emerge”
“This is the most exciting enterprise software initiative I’ve seen since UML”
(Paul Harmon, Senior consultant and Market Analyst, CUTTER consortium, 2001)

30. Early Adopters Interactive Objects Software GmbH Kennedy Carter Kabira
ArcStyler
Kennedy Carter
iUML, iCCG
Kabira
Adaptive Realtime Infrastructure
Secant technologies
Model-Driven Infrastructure
Sun’s NetBeans was added to this list on May 7th 2002
…stay tuned!

31. Conclusions (1/2)
Abstracting out the structure and behaviour of a system in the PIM makes easier:
To validate the correctness of the model
To produce implementations on different platforms
The application of tool supported solutions

32. Conclusions (2/2)
The major drawback is that MDA does not provide a standard for the specification of mappings
Different implementation of mappings can generate very different code or models
This can create dependencies between the software and the mapping solution used

33. 5. References

34. Bibliography (1/3) MDA Specification:
Model Driven Architecture specification, OMG Architecture board, July 2001
Introduction and overview of MDA:
Model Driven Architecture: An introduction, R.M. Soley
Model Driven Architecture, Richard M.Soley (OMG CEO), November 2000
CWM and MOF definitions:
Model-Driven Architecture: Vision, Standards and Emerging Technologies, John D.Poole, ECOOP April 2001
Inserire link a documenti?

35. Bibliography (2/3) CWM examples: System Development Lifecycle in MDA:
Enterprise CORBA 2001 – CWM, Pete Rivett
System Development Lifecycle in MDA:
Developing in OMG’s Model-Driven architecture, Jon Siegel, November 2001
Middleware definition:
Software Engineering and Middleware: A Roadmap, W.Emmerich
The DoD survey on PLs:
A survey of Computer Programming Languages Currently used in the DoD, A.Hook et al., 1995

36. Bibliography (3/3) Conclusions and future trends:
Pratical experiences in the application of MDA, M. de Miguel et al.
MDA: An Idea whose time has come, Paul Harmon
Kennedy Carter’s xMDA:
F-16 Modular Mission Computer Application Software, Lauren E.Clark et al.

37. Webliography MDA documentation: ArcStyler:
ArcStyler:
Kennedy Carter’s iUML and iCCG:
NetBeans:

38. The End

39. Platform
Technological and engineering details that are irrelevant to the fundamental functionality of a software component

40. UML Profile
A standardized set of extensions (stereotypes and tagged values)
Defines an UML environment tailored to a particular use, such as modeling for a specific platform
UML profile for CORBA was standardized in 2000

41. Common Warehouse Metamodel (1/2)
OMG’s data warehouse standard
Enable easy interchange of
warehouse and business intelligence metadata between
warehouse tools
warehouse platforms and
metadata repositories
in distributed heterogenous environments.
Defined using MOF

42. Common Warehouse Metamodel (2/2)
Comprised of a number of constituent metamodels representing:
Data resources
Analysis
Warehouse management
Foundational components
of a typical data warehousing/business intelligence environment
Drawn using UML profile for MOF
More on CWM…

43. Example: the Relational Metamodel

44. CWM: correspondances between models
Area
Metadata
Data
Object
Oriented
Package
Class
Attribute
Extent
Object
Data Value
Relational
Catalog/ Schema
Table
Column
RowSet
Row
Column
Value
Record
RecordFile
RecordDef
Field
RecordSet
Record
Field
Value
XML
Schema
ElementType
Attribute
Document
Element
Data Value

45. MOF (Meta Object Facility)
OMG’s standard for defining metamodels
Provides standard modeling and interchange constructs used in MDA
UML and CWM are defined in terms of MOF constructs
The three main metadata modeling constructs provided by the MOF are:
Class
Association
Package
MOF is an OMG standard defining a common, abstract language for the specification of metamodels.
It is an example of meta-metamodel (or model of a metamodel)

46. Mappings
Mapping is defined as a set of rules and techniques used to modify one model in order to get another model
Mappings are described using UML
It is an example of meta-metamodel (or model of a metamodel)

47. Refining Makes a model less abstract
Permits “zooming” in (and out of) a model:
Il simbolo con l’ovale al centro rappresenta un’interazione
Ha un significato più forte di composition
Attualmente UML non supporta il refining in questo modo (UML 2.0 si?)

48. PIM to PIM mapping
Used when models are enhanced, refined or filtered during the development lifecycle without needing any platform dependant information
Example: analysis to design models transformation
Refining = zooming in and out

49. PIM to PSM mapping (1/3)
This transformation is used when the PIM is projected to the execution infrastructure
Projection is based on platform characteristics
These characteristics should be described using a UML description (and eventually a profile for describing common platform concepts)
There are multiple ways to transform a PIM into a corresponding PSM
Refining = zooming in and out
Specializing = riformulare il modello da un altro punto di vista
More on mapping

50. PIM to PSM mapping: techniques (2/3)
A human could study the PIM and:
Manually construct a platform-specific model
Utilize models of known refinement patterns to reduce the burden in constructing the PSM
Refining = zooming in and out
Specializing = riformulare il modello da un altro punto di vista

51. PIM to PSM mapping: techniques (3/3)
An algorithm could:
Be applied to the PIM and create a skeleton of the PSM to be manually enhanced by hand
Create a complete platform specific model from a complete platform independent model, explicitly or implicitly recording the relation for use by other automated tools
Refining = zooming in and out
Specializing = riformulare il modello da un altro punto di vista

52. PSM to PSM mapping
This transformation is needed for component realization and deployment
Generally related to platform dependent model refinement
Refining = zooming in and out
Specializing = riformulare il modello da un altro punto di vista

53. PSM to PIM refactoring
This transformation is required for abstracting models of existing implementations in a particular technology into a platform independent model
Represents a “mining” process hard to be fully automated
Result of this transformation will match the corresponding PIM to PSM mapping
Refining = zooming in and out
Specializing = riformulare il modello da un altro punto di vista

54. Infrastructure
A set of software or hardware pieces assumed to be already present by some stakeholders when he/she develops a software artifact
Stakeholder=“colui che tiene le scommesse”???

55. Core models The core target platforms of the MDA:
CORBA
Java/EJB
C#/.NET
XML/SOAP
MDA provides UML profiles for these target platforms

56. Pervasive Services Essential services for many applications
transactions
directory services
security
persistance
others…
OMG will define them at PIM level

57. OMG Domain Models
Standardization of services in specific vertical markets
They will be in the form of normative PIMs expressed using UML, augmented by normative PSMs for at least one platform
They are being developed by OMG’s DTFs (Domain Task Forces)
Vedi MDA pag.8

58. The DoD survey of programming languages
Report on programming languages used in the DoD (1995)
In 1995 there were more than 2500 PLs worldwide
Total SLOC by gp third generation languages:

59. Some of the OMG members:
AT&T
BEA
Borland
Boeing CA
Citigroup
Compaq
Ericsson
Ford
Fujitsu
Glaxo HP
Hitachi
Hyperion
IBM
IONA
io Software
Kabira KC
John Deere
Microsoft
MITRE
MSC Soft
NASA
NEC
NetGenics
NTT
OASIS
Oracle
Pfizer
Rational
SAGA
SAP
SAS
Secant
Siemens
Sprint
Sun
Unisys
Vertel

60. IoSoftware’s ArcStyler

61. ArcStyler Success Story
Deutsche Bank Bauspar AG used ArcStyler to embed existing COBOL mainframe application into modern web-based system
A customized Cartridge was created

62. The KC’s xMDA approach
xMDA: eXecutable UML + MDA

63. xMDA Success story
Lockheed Martin used MDA to develop the F-16 Modular Mission Computing software
They used the KC’s iUML tool and more recently iCCG (intelligent Configurable Code Generator) to specify an Ada code generator which can automatically generate 100% of the implementation