1. Made available under EPL 1.0OCL - The Bigger PictureEdward
Willink, Willink Transformations LtdEclipse Projects: OCL, MMT,
QVTd, QVTo, UMLXOMG RTFs (representing Nomos): OCL, QVT, UMLBigMDE
2013, Budapest17th June 2013
2. 17-June-2013 OCL - The Bigger Picture 2Made available under
EPL 1.0OverviewBig MDEbig problemsdisproportionately big
problemsSmall MDEsmall problemsinsignificant in the
smallsignificant in the largeBig MDEdisproportionately small
problems 3. 17-June-2013 OCL - The Bigger Picture 3Made available
under EPL 1.0BackgroundElectronic/Systems Engineeringpoor quality
toolsmake things bettermake things reuseablemake things
rightspecification not implementation 4. 17-June-2013 OCL - The
Bigger Picture 4Made available under EPL 1.0OCL utilityexecutable
specification languagerightuseablereuseableunuseableside effect
freenothing can changeneeds objectsonly useful within a larger
contexttransformation languages 5. 17-June-2013 OCL - The Bigger
Picture 5Made available under EPL 1.0Systems 6. 17-June-2013 OCL -
The Bigger Picture 6Made available under EPL 1.0Block DiagramsLow,
medium or high levelFriendly Convey an apparently simple meaning
Open to reviewEach element Independent continuously operating 7.
17-June-2013 OCL - The Bigger Picture 7Made available under EPL
1.0SubsystemsSystems too complicatedbreak down in to
subsystems/subsubsystems/...Subsystems availableadd value to create
a SystemWhat does it actually mean to composesubsystems ?compatible
interface .... communication 8. 17-June-2013 OCL - The Bigger
Picture 8Made available under EPL 1.0Subsystem Interface
CompatibilityContent compatibilityfeet/pounds or metres/kilograms
?model conforming to structural metamodeltypes conforming to
semantic metamodelCommunication
compatibilityproducer/consumerclient/server... 9. 17-June-2013 OCL
- The Bigger Picture 9Made available under EPL 1.0Communication
Link is two endedBoth ends must co-operateAll links must
co-operateshare bandwidthavoid deadlocksreduce latenciesprovide
securityprovide reliability.... 10. 17-June-2013 OCL - The Bigger
Picture 10Made available under EPL 1.0Component Oriented
Communicationsprovide a sink/sourceloop foreverwait till inputs
availableget inputscompute outputs and update stateput
outputsBlockinputs outputsstate 11. 17-June-2013 OCL - The Bigger
Picture 11Made available under EPL 1.0Trivial DeadlockOopsboth
waiting for inputsneither generating outputDeadlock (with just 2
components!)BlockAinputs outputsstateBlockBinputs outputsstate 12.
17-June-2013 OCL - The Bigger Picture 12Made available under EPL
1.0Eclipse System PerformanceEclipse 3.0 to 3.4 steadily
fasterincremental editor/compilerincremental builderEclipse 3.5 to
3.9/4.3 steadily slowerinnovative new projectsindisciplined use of
component-level APIs(e4 is far from being the major culprit) 13.
17-June-2013 OCL - The Bigger Picture 13Made available under EPL
1.0Stupid Livelock Example1: Every source file shall be reviewed
after any change2: Every source file shall contain a review
recordOops:real change =>review =>review record change
=>review =>review record change => 14. 17-June-2013 OCL -
The Bigger Picture 14Made available under EPL 1.0Real Example1: The
Model Index shall contain a summary of all models2: The Model Index
shall be updated when a model changes3a: The Model Index shall be
accessible as a model3b: A model shall be autogenerated from ...3c:
Another Model Index shall contain a summary of all models3d: A
Configuration Management State ....In practice the infinite loop is
only stabilized by:an unmodified output file shall not be written
15. 17-June-2013 OCL - The Bigger Picture 15Made available under
EPL 1.0Communication DesignRequirements of the system=>
partitioning of computations=> distribution over
processes/processors=> requirements on the communicationscan be
fundamentally relibaleBottom up subsystem reuse=> communication
anarchyComponents must suit the system 16. 17-June-2013 OCL - The
Bigger Picture 16Made available under EPL 1.0Mutable
ComponentsImplementationsnumerous configuration options(very)
bloated interfacescompromised
performanceSpecificationsauto-generated implementationnumerous
configuration optionsunwanted functionality gets optimized awayDead
Specification Elimination 17. 17-June-2013 OCL - The Bigger Picture
17Made available under EPL 1.0Requirements
SpecificationImplementation 18. 17-June-2013 OCL - The Bigger
Picture 18Made available under EPL 1.0The basic software production
problemSimpleProblemtoo
hardprogressionsdistractionsmodelsSpecificationCodeAssemblerCCIMPIMPSMModelsMacroAssemblerC++,
Java, ..Aspect ... 19. 17-June-2013 OCL - The Bigger Picture 19Made
available under EPL 1.0MDA
YPlatformIndependentModelPlatformSpecificModelPlatformModelPIMwhat
needsto be doneprogram/applicationmodelswhat resourcesare
availableprogram/algorithm/applicationlibrarieshardware/operating
systemdefinition modelsPSMwhat actually getsdone -- the code 20.
17-June-2013 OCL - The Bigger Picture 20Made available under EPL
1.0Better MDA YSpecification + Hints + Reality =>
SolutionPlatformIndependentModelPlatformSpecificModelPlatformModelMark
ModelMM - the manualintervention do the JPEG on thegraphics
processor use a non-reentrantQuickSort algorithm for ... use TCP to
satisfytransmission guaranteesPSM - the 100%autogenerated solution
21. 17-June-2013 OCL - The Bigger Picture 21Made available under
EPL 1.0Aspect Oriented MDAToo many problems to solveat oncedivide
and conquersolve one concern at a
timeprecisionschedulingpartitioninglatencyintegritymiddlewarecode
generationConcern ACodeModelsConcern BConcern CSpecificationConcern
ZPlatform Hints 22. 17-June-2013 OCL - The Bigger Picture 22Made
available under EPL 1.0MetaModel Typed MDAAll models conform to
their meta-modelsM Ain MM AinM Aout MM AoutIn practice not all of
meta-model is usedM Ain MM Ain MM AinM Aout MM Aout MM AoutM Bin MM
Bin MM BinM Bout MM Bout MM BoutCompatibilityM Aout M BinMM Aout MM
Bin[MM Aout MM Bin too strong]Concern ACodeMM AinModelsConcern
BConcern CSpecificationConcern ZMM BinMM BoutMM AoutMM CinMM CoutMM
ZinMM Zout 23. 17-June-2013 OCL - The Bigger Picture 23Made
available under EPL 1.0Traditional ModelingUML Analysis
Diagramspoor quality toolsmajor analysis/design disconnectUML
Design Diagramsdifficult to capture behaviouropaque code generation
templatestroublesome reverse engineering cyclesVery productive in
well-suited narrow domainsstate/protocol machinesCounter productive
in more general applications 24. 17-June-2013 OCL - The Bigger
Picture 24Made available under EPL 1.0The Action ProblemAction code
does not model wellAny systemhas a statecomprising many
variablescan be represented as an instance of a meta-modelevent
occurssometimes comprising a messagecan be represented as an
instance of a meta-modelhas an updated statecomprising many
variablescan be represented as an instance of a meta-model 25.
17-June-2013 OCL - The Bigger Picture 25Made available under EPL
1.0State change as model transformationAny state changecan be
treated as an atomic model transformationfromold stateinput
messagetonew stateoutput
messagesModelTransformationInputMessageOutputMessage(s) 26.
17-June-2013 OCL - The Bigger Picture 26Made available under EPL
1.0In-place transformationsEmbedded systemsin-place transformation
(human)old state can be accidentally corrupted while computing new
statehybrid old/new state can be inadvertently accessedin-place
transformation (declarative)tooling must sequence old reads, temp
stores, new writestooling must hide access during finite duration
atomic
changeModelTransformationAInputMessageOutputMessage(s)ModelTransformationBInputMessageOutputMessage(s)
27. 17-June-2013 OCL - The Bigger Picture 27Made available under
EPL 1.0Declarative model transformationRelationship between
Input(s) and Output(s)no internal side effectsvery disciplined form
of model mutationcan be expressed in
OCLModelTransformationInputMessageOutputMessage(s) 28. 17-June-2013
OCL - The Bigger Picture 28Made available under EPL 1.0Model
transformation as OCLself organizing (small changes)every node
notifies changesevery node listens for relevant changesOCL analysis
configures the listenerschange just ripples through affected graph
nodesstrategic (large changes)transformation directly pokes the
affected nodesOCL EquationsDirected GraphInput Objectsand
MessagesOutput Objectsand Messages 29. 17-June-2013 OCL - The
Bigger Picture 29Made available under EPL 1.0Models of
CompuationHow, When, Why computations happenfundamental to Digital
Signal Processinginsufficiently known more generallyLee, E.A.,
Messerschmitt, D.G.: Synchronous data flow.Proceedings of the IEEE
75(9), 12351245 (1987) 30. 17-June-2013 OCL - The Bigger Picture
30Made available under EPL 1.0Java Model of Computationdouble
f(double x, double y)double p,q,r;p = x + 1;q = y - 1;r = p +
q;return r;}When f is invoked (unknown mechanism)execution proceeds
statement by statementResult is returned (unknown
mechanism)Validity of variables is assumed to be okcommunication
exists as a side effect 31. 17-June-2013 OCL - The Bigger Picture
31Made available under EPL 1.0Java Model of Computation -
Oopsdouble f(double x, double y)double p,q,r;r = p + q;p = x + 1;q
= y - 1;r = p + q;return r;}Validity of variables is no longer
okcommunication failsmay get uninitialized variable warningin
general, just get a malfunction 32. 17-June-2013 OCL - The Bigger
Picture 32Made available under EPL 1.0System/subsystem viewData
dependencies are now clearcannot misscheduleWhat happens when?no
one right answer+ 33. 17-June-2013 OCL - The Bigger Picture 33Made
available under EPL 1.0Continuous Time MoCExecuting on analogue
hardwareeach partial computation has its own hardwareoccurs
continuouslypropagation delay from input to output 34. 17-June-2013
OCL - The Bigger Picture 34Made available under EPL
1.0SimulationDedicated hardware per
computationimpracticalinaccurate/unstableunnecessarily
redundantSimulationfast enough to give comparable resultsshare
hardware 35. 17-June-2013 OCL - The Bigger Picture 35Made available
under EPL 1.0Data Flow MoCEach node processes when readyabsorbs a
token from each inputproduces a token at each outputpropagation
delay from input to output 36. 17-June-2013 OCL - The Bigger
Picture 36Made available under EPL 1.0Synchronous Data Flow MoCAll
input tokens appear at onceno need for physical tokenssynthesize a
legal schedulep = x+1; q = y-1; r = p+q;q = y-1; p = x+1; r = p+q;
37. 17-June-2013 OCL - The Bigger Picture 37Made available under
EPL 1.0Discrete Event MoCInputs may change one at a timevariables
have persistent statex changes:p = x+1; r = p+q;y changes:q = y-1;
r = p+q; 38. 17-June-2013 OCL - The Bigger Picture 38Made available
under EPL 1.0Practical ConsequencesIncremental editorediting 10
line file has cost Tediting a 10,000 line can be
