mda architecture

8/8/2019 mda architecture

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Vliohjelmistot - Lea Kutvonen 1

MDAModeldriven

architecture


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Contents What is MDA?

Challenges for MDA

Program generation from models MDA terminology

Basic modeling technology

Modeling language extensibility

Building a MDA application Model transformations (information, activities)

About tools


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What is MDA? using modeling languages as declarative

progamming languages

rising of abstraction level for programmers improved productivity, quality, longevity outlook

has been used to generate real-time andembedded systems although term MDA

coined later strategic direction of OMG as announced in 2002)

Java community process, ebxml, rosettanet usingsimilar concepts


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Challenges for MDA B2B and B2C integration needs of enterprises

Reguirement: Preserve investment

As enterprise borders shift requiring platform shift

As platforms themselves change EJB 1.1 --> EJB 2.0

XML --> XML Schema

MTS --> COM+

CORBA 2.0 --> CORBA 3.0

Solution: Isolate information and processing logic from technologyspecifics

Build platform independent models UML is independent of CORBA, COM, EJB, XML, etc thus is well-suited as a

language for dexcribingn

Map these models to specific platforms

Maintain the separation at the implementation level


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Enterprise and its boundaries

Frankel:2001


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No Universal Component Middleware

CORBA EJB .NET . . .

Major Challenge!


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Integration communication

Frankel:2001


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Enterprise system integration trend

middleware addresses integration within theenterprise with a distributed computer

today aim for similar integration betweenenterprises Avoid typing in from computer-printouts

ebXML, .NET, RosettaNet and other Web

Services initiatives aim to be themiddleware to link enterprises How to cope with them all?


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Rising the level of abstraction Part of general trend

Already well-established front and back ends

WYSIWYG GUI modeling and data modelign Hand coding no longer predominatees

Early web-applications wired web front end directly toback end

Some companies avoided building intermediate tiers Web services and B2B require intermediate tiers to expose coarse

grained business services

Abstraction to allow reuse of the coarse grain business services viavarious technologics.


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Program generation from models MDA is about using modeling languages as

programming languages rather than merely

as design languages can improve productivity, quality, and

longetivity outlook

new term, old invention CASE-tools in 1980s, integrated object-oriented

development environments in 1990s, UML tools,etc.


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New orientation for OMG activities

New step beyond the Object

Management Architecture (OMA) Models are centric!

Target middleware is not important!

Focus on Platform Independent Models (PIM)

Without middleware details

Abstract Platform Specific Models (PSM) Including all middleware details

Define PIM to PSM transformations

Preserving PIM when new middleware appears!

Model Driven

Architecture


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Some Key Terms

Model

A formal specification of the function, structure and/or

behavior of a system. (Model .ne. UML) Platform

Technological and engineering details that areirrelevant to the fundamental functionality of asoftware component.

Platform Independent Model (PIM) A formal specification of the structure and function

of a system that abstracts away technical details(e.g., funds transfer)

Platform Specific Model (PSM)

The technical details (CORBA, SOAP, EJB)


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Basic modeling technology UML unified modeling language

MOF meta object facility XMI XML metadata interchange


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UML IDL as abstraction very limited

generates same level constructs, stubs andskeletons

modeling languages declarative? separation of abstract syntax from concretesyntax

invariants, pre- and postconditions

precise action semantics and standardmappings on various platforms

mappings represent a standard engineeringsolution for a collaboration concept

UML has defined profiles for introducingseparate sets of transformation rules to model particular domain, eg. business

information, busienss services,collaborations, realtime systems, telecom

to parametrize mapping to sepcifictechnologies

class vs. behavioural models


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XMI - XML metadata interchange


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Building an MDA Application

Start with a Platform-Independent Model

(PIM) representingbusiness functionalityand behavior,undistorted bytechnology details.

Platform-

Independent

Model

A Detailed Model,stating Pre- and Post-

Conditions in OCL,

and Semantics inAction Language


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Generating Platform-Specific

Model

Platform-

Independent

Model

Map a PIM to SpecificMiddleware

Technologies via OMG

Standard Mappings

MDA tool applies astandard mapping to

generate Platform-Specific Model(PSM)from the PIM. Code ispartially automatic,partially hand-written.CORBA

Model


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Mapping to Multiple

Deployment Technologies

Platform-

Independent

Model

CORBAModel

MDA tool applies anstandard mapping to

generate Platform-Specific Model(PSM)from the PIM. Code ispartially automatic,partially hand-written.Java/EJB

Model

XML/SOAP

Model

OtherModel

Map a PIM to ManyMiddleware

Technologies via OMG

Standard Mappings

PSM can be viewed as presentation model (Web): data schemas, web comps, etc Business logic model (EJB): data schemas, key classes, etc

Data models (DBMS): tables, columns, keys, etc


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Generating Implementations

Platform-

Independent

Model

CORBAModel

MDA Tool generates allor most of the

implementation codefor deploymenttechnology selectedby the developer.

Java/EJBModel

CORBA

XML/SOAP

Model

Java/EJBXML/SOA

POther

OtherModel

Map PSM to applicationinterfaces, code, GUI

descriptors, SQL

queries, etc.


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Integrating Legacy & COTS

Platform-

Independent

Model

Legacy

App

MDA Tools for reverseengineering automate

discovery of modelsfor re-integration onnew platforms.

COTS

App

Other

OtherModel

Reverse-engineerexisting application intoa model and redeploy.


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Automating Bridges

CORBAModel

XML/SOAP

Model

Platform-

Independent

Model

CORBASystem

XML/SOAP

SystemInterop

Bridge

MDA Toolscombine

application andplatform

knowledge to

generate bridges

Bridge generation issimplified by common

application models,simplifying creation ofintegrated applicationsboth within and acrossenterprises.


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Concepts: Refinement

Billing

Platform Specific

Component Independent

Business Model

Platform Independent

Component view

Platform Specific


Business Model


Component view

Service Provisioning

Platform Specific


Business Model


Component view

Service Provisioning

Platform Specific


Business Model


Component view

Computation

independent

Platform

independent


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Concepts: Patterns

Billing

Platfor Specific

CORBA

usiness odel

Platfor Independent

Platfor Specific

CORBA

usiness odel

Platfor Independent

Service rovisioning

Platfor Specific

CORBA

Business odel

Platfor Independent

PI toorba

PI toorba

PI toorba


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Concepts: Packages

Package P1

Syste fro vie point 1

Package P2

Syste fro vie point 2

Package P3

Interrelationship bet een P1 andP2

Package P4

Abstraction

Package P5

Refine ent Relation

Package P6

Realization(a) (b)


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MDA Example

Credit:


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PIM, PSM, and

Transformations in MDA

TRANSFORMATION RULES

Platform SpecificModel(PSM)

Platform Independent Model

(PIM)

Platform SpecificModel(PSM)


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PIM to PSM TransformationExamples with MOF/XMI

UML Model (PIM)

Aut

l r : Stri g

D r : I t g r

E gi : I t g r

Red

4

2

XMI Document (PSM)

XMI

(Color*,

Door*,

Engine*)>

XMI DTD, Schema (PSM)

interface Auto{

};

IDL, Java (PSM)

Class Auto

{public String color;

public int Door;

public int Engine;

}


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Transformation Models in MDAPIM

Software

Infrastructure

PSM

J2EE

PIM

HealthCare

Business

Application

.Net

PIM to PSMTransformation

Model

J2EE

PSM

.N

et


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Why New Component Models? Often application designers want to use

concepts not present in PSM

e.g. CCM has no active JavaBeans properties

1) Creating a new PSM but also requires todevelop

the associated middleware Very expensive and time consuming!!!

2) Creating a new PIM and defining PIM to PSM

transformation rules


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The Message Filtering

ExampleA filter has

1 input for receiving messages to filter

Configurable filtering properties

1 filtering function

1 output for accepted messages

1 output for rejected messagesFilter

P1 = V1P2 = V2

F = M.C1 == P1 or M.C2 > P2

OK

N

O


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Application = Assembling Filters


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Problems All must be done manually!

Defining OMG IDL for message eventtypes, filter componentand home types

Implementing CCM eventtypes, components and homes

Writing CCM XML descriptors

Extremely verbose, time consuming and errorprone!!!

How improving productivity and quality? How dealing with thousand messages and filters?

How dealing with other Message OrientedMiddleware (MOM)? Like EJB 2.0 message beans


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Next Step on the Message Filtering

Meta-Model Only allow definition of message and filter

types

Only generate OMG IDL types,implementations, and CCM XML packagingdescriptors

Complete the meta model to describe filterinstances and connections between them

Then allow generation of CCM XMLassembling descriptors for automatic

deployment


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Drawback around

MDA-oriented Tools Few MOF compliant tools to experiment the creation

of new component meta models!

Developing UML profiles are time and money

consuming UML Profile Builders are still expensive and proprietary

No portability of developed UML profiles betweenUML Tools!!!

Few formalisms to express MDA transformation OMG RFP under work

Few PSM meta models for Programming languages like Java, C++,

Component standard middleware


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MDA vs. CASE

CASE limitations

Mappings to implementation technologies

were proprietary Risk to CASE customers too great

Very limited to extend specificationlanguage

MDA overcomes these limitations

Standardized mappings, for each domain

UML profiles and MOF


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Kirjallisuutta Siegel, Jon, Developing in OMGs Model-Driven

Architecture. Object Management Group WhitePaper, Nov 2001.ftp://ftp.omg.org/pub/docs/omg/01-12-01.pdf(pakkollinen)

OMG Architecture Board, Model Driven Architecture(MDA), Jul 2001, ORMSC/2001-07-01http://cs.ua.edu/630/Resources/MDA%20White%20P

apers/MDA%20-%20Technical%20Perspective%20-%20OMG%20Board%20-%20ormsc-01-07-01.pdf

(tydentv)


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Varhaisia vlineit iUML, ICCG www.kc.com

Adaptive framework www.adaptive.com

www.kabira.com

ArchStyler (in Borlands Enterprisestudio 2) www.io-software.com

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