Architecture As Language

Architecture As Language
Andreas Graf
MarkusVoelter
www.itemis.degraf@itemis.de
www.voelter.devoelter@acm.org

About

1
What is a language?

INFORMAL
Set of well-definedterms

INFORMAL
Stakeholders
agree on meaning

FORMAL
Metamodel

FORMAL
Metamodel
Grammar

FORMAL
Metamodel
Grammar
Notation

A DSL is a focussed, processablelanguagefor describing a specific concernwhen building a system in a specific domain. Theabstractionsandnotationsused are natural/suitablefor the stakeholderswho specify that particular concern.

2
Architecture DSLs

Architecture
DSL

As you understand
anddevelopyour
Architecture…

Develop a languageto express it!

Language resemblesarchitecturalconcepts

We express theapplication(s) withthelanguage.

DEMO I
An architectural DSL for embedded systems

3
Benefits

Clear Understanding
frombuildingthelanguage

Unambigious
Vocabulary

Conceptsindependent
from Technology

Programming Model canbedefinedbased on ConceptualArcitecture

Architecture„executable“
(i.e. morethanrulesanddocs)

4
Why Textual?

4
… or:why not graphical?

Languagesand Editors
areeasiertobuild

Languagesand Editors
areeasiertobuild
Evolve Language and simple editorasyou understand anddiscussthearchitecture, in real time!

Integrateseasilywithcurrentinfrastructure:
CVS/SVN diff/merge

Model evolutionistrivial, youcanalwaysusegrep.
adaptingexistingmodelsasthe DSL evolves

Many Developers
prefertextualnotations

When a graphical
notation
isbetter, youcanvisualize.

5
Tooling

Severaltoolsavailable.
Example:oAWXtext

SpecifyGrammar

AntlrGrammarandParserisgeneratedfromthisspecification

Generated Metamodel

SpecifyConstraints

Generated Editor

DEMO II
The language-aware editor for our DSL

6
Generating Code

Sincewealready
have a formal model….

Generate API
MapsArchitecturalConceptsto
Implementationlanguage (non-trivial!)

Implementation
Implementationonlydepends onthegeneratedprogramming model API

Programming Model
Generated API + Usage Idioms
Completely Technology-Independent

Runtime Infrastructure
Select based on fit wrt. toarchitectural
conceptsand non-functionalrequirements

Glue Code
Aka Technology Mapping Code
Maps API toselectedplatform

Glue Code
ContainsConfiguration Files forPlatform
Mightrequire „mix in models“

SeveralPlatforms
Different Platforms, not Languages
Support forScaling (non-functionalreq)
Testing!

Benefits:More EfficientImpl.
Technology Independent
Consistence/Quality
Architecture-Conformance

Code Gen Sequence
1) Generate API
2) Write Impl Code
3) Select Platform
4) GenerateGlue Code

Separate Models
forstuff relevant forthe API
vs. system/deploymentstuff

DEMO III
Generating C for the
target device

7
Expressing Variability

Different Variants
ofthe System
for different customers.

How do I
express
this in themodels?

Negative Variability:
Conditionallytakingsomethingaway

Negative Variability:
Conditionallytakingsomethingaway
Feature Models

componentDelayCalculator {
provides default: IDelayCalculator
requires screens[0..n]: IInfoScreen
providesmon: IMonitoringfeature monitoring
}

namespacemonitoringStufffeature monitoring {

componentMonitoringConsole {
requires devices:[*]: IMonitor
}
instance monitor: MonitoringConsole
dynamicconnectmonitor.devicesquery {
type = IMonitor
}

}

Positive Variability:Conditionallyaddingsomethingto a minimal core

Positive Variability:Conditionallyaddingsomethingto a minimal core
Aspects

namespacemonitoring {

componentMonitoringConsole …
instance monitor: …
dynamicconnectmonitor.devices …

aspect (*) component {
providesmon: IMonitoring
}
}

…
}
componentAircraftModule {
…
}
componentInfoScreen {
…
}