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![OUR CONTRIBUTION
11
A notion of transformation product line (TPL), which is:
• Compact: transformation fragments, annotated with their activation
(presence) conditions
• Usable: abstraction mechanism that hides details (concepts)
• Extensible: by composition operators
• Correct: by profiting from (OCL) contracts and analysis methods
based on model finding
Building on a notion of meta-model product line (MMPL) [GLCS18]
Tool support: Merlin
Experiments that show the benefits of analysis at the TPL level
[GLCS18] Guerra, de Lara, Chechik, Salay. 2018.
Analysing Meta-Model Product Lines. Proc. SLE, pp.: 171-184.](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-11-320.jpg)
![CONCEPTUAL MMPLs
Make uniform the 150% meta-model
Concept on top of the 150% meta-model
• A canonical representation of common elements
• Binding to different variants
Express expectations on the different variants (constraints)
16
ins
Place
tokens: int
PetriNet
Transition
outs
places * trans*
*
*
posTokens inv:
self.tokens >= 0
PetriNet
+places(): Place[*]
+trans(): Transition[*]
Place
+tokens(): int
Transition
+ins(): Place[*]
+outs(): Place[*]
posTokens inv:
self.tokens() >= 0
](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-16-320.jpg)
![context PetriNet
def: places() : Place[∗] = self.places
def: trans() : Transition[∗] = self.trans
context Transition
def: ins() : Place[∗] = self.ins
def: outs() : Place[∗] = self.outs
context Place
[Simple] def: tokens() : Integer = self.itokens
[Object] def: tokens() : Integer = self.ctokens→size()
PL OF BINDINGS
17
Constraints and transformations are written against the concept
Now we can write one constraint, instead of two (with simpler PC):
context Place
[Bounded] inv boundedTokens: self.tokens()<=bound
PetriNet
+places(): Place[*]
+trans(): Transition[*]
Place
+tokens(): int
Transition
+ins(): Place[*]
+outs(): Place[*]
posTokens inv:
self.tokens() >= 0](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-17-320.jpg)
![TPL EXAMPLE
21
operation PetriNet step() : Boolean {
var enabledTrans = self.trans()->select(enabled());
if (enabledTrans->isEmpty()) return false;
else return self.pick(enabledTrans).fire() ;
}
[Simple] operation Place modify(t : Integer) {
self.itokens += t;
}
[Object] operation Place modify(t : Integer) {
if (t>0)
for (i in Sequence{1..t})
self.ctokens.add(new Token);
else if (t<0)
for (i in Sequence{1..-t})
self.ctokens.remove(self.ctokens.random());
}](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-21-320.jpg)
![EXTENDING TPLs
22
context PetriNet
[not Priority] def: pick(s: Set(Transition)): Transition= s→any(true)
[Priority] def: pick(s: Set(Transition)): Transition=
s→any(t | not s→exists(t1| t1.priority>t.priority))
context Transition
[not (Inhibitor or Read or Bounded)]
def: enabled() : Boolean = self.ins()→forAll(tokens()>0)
[Inhibitor and not (Read or Bounded)]
def: enabled() : Boolean = self.ins()→forAll(tokens()>0) and
self.inh→forAll(tokens()=0)
[Inhibitor and Read and not Bounded]
def: enabled() : Boolean = self.ins()→forAll(tokens()>0) and
self.inh→forAll(tokens()=0) and
self.read→forAll(p.tokens()>0)
… (5 more combinations ommited)
Still difficult to extend!](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-22-320.jpg)
![COMPOSING RULE BODIES
OVERRIDING
Override: declares precedence among rule bodies
• Default (super): more specific body overrides more general body
• Other semantics: subs, all
23
context PetriNet
def: pick(s: Set(Transition)): Transition =
s→any(true)
context PetriNet
[Priority]
−− @Override super
def: pick(s: Set(Transition)): Transition=
s→any(t | not s→exists(t1| t1.priority>t.priority))](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-23-320.jpg)
![Merge operators depending on rule signature
• and/or for boolean queries, union/intersection for collections
• Arithmetical operations for queries returning numbers
• Sequential composition of actions for operations changing state
24
context Transition
def: enabled(): Boolean = ins()→forAll(tokens()>0)
COMPOSING RULE BODIES
MERGE
context Transition
−− @Merge and
[Inhibitor] def: enabled(): Boolean = inh→forAll(tokens()=0)
context Transition
−− @Merge and
[Read] def: enabled(): Boolean = read→forAll(tokens()>0)
context Transition
−− @Merge and
[Bounded] def: enabled(): Boolean=outs()→forAll(tokens()<bound)
4combinations
insteadof8](https://image.slidesharecdn.com/mtpls-181017195923/85/MTPLs-24-320.jpg)
Uploaded bymiso_uam
MTPLs
The document discusses developing a transformation product line (TPL) approach to define model transformations over variants of a meta-model product line (MMPL) in a compact, reusable, extensible, and analyzable way by using transformation fragments with presence conditions and composing them through abstraction and overriding mechanisms. It aims to address the challenges of defining transformations over many variants of a meta-model in a scalable way while maintaining correctness through analysis at the TPL level.
More Related Content
MTPLs
- 1. MODEL TRANSFORMATION PRODUCT LINES MODELS’2018,Copenhagen J. de Lara1, E. Guerra1, M. Chechik2, R. Salay2 1Universidad Autónoma de Madrid (Spain) 2University of Toronto (Canada)
- 2. LET’S WRITE ASIMULATOR FOR PETRI NETS… 2 ins Place tokens: int PetriNet Transition outs places * trans* * * operation Transition fire() { for (p in self.ins) p.tokens-=1; for (p in self.outs) p.tokens+=1; } …
- 3. DOES THIS LOOKFAMILIAR? 3 ins Place PetriNet Transition outs places * trans* * * Token tokens * operation Transition fire() { for (p in self.ins) p.tokens.remove(p.tokens.random()); for (p in self.outs) p.tokens.add(new Token); } … ins Place tokens: int PetriNet Transition outs places * trans* * * operation Transition fire() { for (p in self.ins) p.tokens-=1; for (p in self.outs) p.tokens+=1; } …
- 4. NOT ONLY REALIZATIONS, BUTVARIANTS… 4 ins Place tokens: int bound: int PetriNet Transition outs places * trans* * * Bounded places ins Place tokens: int PetriNet Transition outs places * trans* * * Transition priorities priority: double ins Place tokens: int PetriNet Transition outs places * trans* * * Read arcs read * ins Place tokens: int PetriNet Transition outs places * trans* * * Inhibitor arcs inh *
- 5. …WHICH WE MAYNEED TO COMBINE 5 ins Place tokens: int bound: int PetriNet outs places * trans* * * Bound + priorities (int) Transition priority: double ins Place bound: int PetriNet outs places * trans* * * Bound + priorities (class) Transition priority: double Token tokens * ins Place PetriNet Transition outs places * trans* * * read * tokens: int bound: int Bound + read arcs (int) ins Place PetriNet Transition outs places * trans* * * read * bound: int Bound + read arcs (class)Token tokens *
- 6. ins Place tokens: int bound: int PetriNet outs places* trans* * * Bound + priorities (int) Transition priority: double ins Place bound: int PetriNet outs places * trans* * * Bound + priorities (class) Transition priority: double Token tokens * ins Place PetriNet Transition outs places * trans* * * read * tokens: int bound: int Bound + read arcs (int) ins Place PetriNet Transition outs places * trans* * * read * bound: int Bound + read arcs (class)Token tokens * …WHICH WE MAY NEED TO COMBINE 6 32 combinations
- 7. ins Place tokens: int bound: int PetriNet outs places* trans* * * Bound + priorities (int) Transition priority: double ins Place bound: int PetriNet outs places * trans* * * Bound + priorities (class) Transition priority: double Token tokens * ins Place PetriNet Transition outs places * trans* * * read * tokens: int bound: int Bound + read arcs (int) ins Place PetriNet Transition outs places * trans* * * read * bound: int Bound + read arcs (class)Token tokens * …AND WRITE TRANSFORMATIONS FOR 7 Now go and write 32 transformations
- 8. ins Place tokens: int bound: int PetriNet outs places* trans* * * Bound + priorities (int) Transition priority: double ins Place bound: int PetriNet outs places * trans* * * Bound + priorities (class) Transition priority: double Token tokens * ins Place PetriNet Transition outs places * trans* * * read * tokens: int bound: int Bound + read arcs (int) ins Place PetriNet Transition outs places * trans* * * read * bound: int Bound + read arcs (class)Token tokens * …AND MAINTAIN 8 Do we add weights to the arcs?
- 9.
- 10. WHAT WE NEED Asuccinct mechanism to express meta-model variants Methods to write transformations for all these variants • Compact: without writing many similar-but-not-quite-the- same transformations • Usable: abstract away from details of other variants • Extensible: easy to add new variants • Correct: express and check expectations on different parts of the transformation 10
- 11. OUR CONTRIBUTION 11 A notionof transformation product line (TPL), which is: • Compact: transformation fragments, annotated with their activation (presence) conditions • Usable: abstraction mechanism that hides details (concepts) • Extensible: by composition operators • Correct: by profiting from (OCL) contracts and analysis methods based on model finding Building on a notion of meta-model product line (MMPL) [GLCS18] Tool support: Merlin Experiments that show the benefits of analysis at the TPL level [GLCS18] Guerra, de Lara, Chechik, Salay. 2018. Analysing Meta-Model Product Lines. Proc. SLE, pp.: 171-184.
- 12. META-MODEL PRODUCT LINES: FEATUREMODEL Feature model to express the variability space Features and their allowed combinations Feature diagram Configurations 12 mandatory optional alternative or PetriNets Tokens Simple Object Priority FM = {PetriNets, Tokens, Simple, Object, Arcs, Inhibitor, Read, Priority, Bounded}, PetriNets Tokens Arcs ((Simple ¬Object) (¬Simple Object)) Arcs Inhibitor Read Bounded Legend P = {⟨Simple⟩, ⟨Simple, Inhibitor, Bounded⟩, ⟨Object, Read, Priority⟩, . . . } (32 are possible, only leaf features shown)
- 13. META-MODEL PRODUCT LINES: 150%META-MODEL 13 ins Place itokens: int bound: int PetriNet Transition outs places Simple 1 * trans* 1 Token ctokens * 1 Object Object * * priority: double read* Read Priority * inh Inhibitor Bounded boundedTokens1 inv: itokens<=bound Bounded Simple boundedTokens2 inv: ctokens→size()<=bound Bounded Object “meta-model” with presence conditions Upon selecting a configuration, a meta-model is derived: • Having only those elements (classes, attributes, referemces, constraints) whose presence condition is true
- 14. META-MODEL PRODUCT LINES: 150%META-MODEL 14 ins Place itokens: int bound: int PetriNet Transition outs places Simple 1 * trans* 1 Token ctokens * 1 Object Object * * priority: double read* Read Priority * inh Inhibitor Bounded boundedTokens1 inv: itokens<=bound Bounded Simple boundedTokens2 inv: ctokens→size()<=bound Bounded Object “meta-model” with presence conditions ins Place itokens: int bound: int PetriNet outs places * trans* * * Transition priority: double ⟨Simple, Bounded, Priority⟩ boundedTokens1 inv: itokens<=bound Bounded Simple
- 15. NEED FOR ABSTRACTION 15 ins Place itokens: int bound:int PetriNet Transition outs places Simple 1 * trans* 1 Token ctokens * 1 Object Object * * priority: double read* Read Priority * inh Inhibitor Bounded boundedTokens1 inv: itokens<=bound Bounded Simple boundedTokens2 inv: ctokens→size()<=bound Bounded Object We are stating the same constraint for two different variants Find a way to abstract away the differences of different realizations Simplify writing constraints and transformations • Ensuring scaling with variant combinations
- 16. CONCEPTUAL MMPLs Make uniformthe 150% meta-model Concept on top of the 150% meta-model • A canonical representation of common elements • Binding to different variants Express expectations on the different variants (constraints) 16 ins Place tokens: int PetriNet Transition outs places * trans* * * posTokens inv: self.tokens >= 0 PetriNet +places(): Place[*] +trans(): Transition[*] Place +tokens(): int Transition +ins(): Place[*] +outs(): Place[*] posTokens inv: self.tokens() >= 0
- 17. context PetriNet def: places(): Place[∗] = self.places def: trans() : Transition[∗] = self.trans context Transition def: ins() : Place[∗] = self.ins def: outs() : Place[∗] = self.outs context Place [Simple] def: tokens() : Integer = self.itokens [Object] def: tokens() : Integer = self.ctokens→size() PL OF BINDINGS 17 Constraints and transformations are written against the concept Now we can write one constraint, instead of two (with simpler PC): context Place [Bounded] inv boundedTokens: self.tokens()<=bound PetriNet +places(): Place[*] +trans(): Transition[*] Place +tokens(): int Transition +ins(): Place[*] +outs(): Place[*] posTokens inv: self.tokens() >= 0
- 18. TRANSFORMATION PRODUCT LINES (TPLs) 18 TranformationDefinition • Meta-model • Rule signatures and contracts (specification) • Rule bodies Transformation Product Line (TPL) • Transformation Definition with variability (bodies with PCs)
- 19. BOUNDED TPLs 19 Tranformation Definition •Meta-model • Rule signatures and contracts (specification) • Rule bodies Transformation Product Line (TPL) • Transformation Definition with variability (bodies with PCs) Bounded TPL • TPL coupled with a CMMPL
- 20. TRANSFORMATION SPECIFICATION 20 Place Transition +modify(t : int): post:self@pre.tokens()+t = self.tokens() +enabled(): boolean {query} post: enabled() implies ins()→forAll(p | p.tokens()>0) and not enabled() implies ins()→exists(p | p.tokens()=0) +fire(): post: ins()→excludingAll(outs())→forAll(p|p@pre.tokens()<p.tokens()) and outs()→excludingAll(ins())→forAll(p|p@pre.tokens()>p.tokens()) PetriNet +simulate(): boolean post: trans()→select(t|t.enabled())→isEmpty() +step(): boolean post: step() implies self@pre.trans()→exists(t|t.enabled()) +pick(s : Set(Transition)): Transition {query} pre: s→size()>0 and s→forAll(t|t.enabled()) post: s→includes(result)
- 21. TPL EXAMPLE 21 operation PetriNetstep() : Boolean { var enabledTrans = self.trans()->select(enabled()); if (enabledTrans->isEmpty()) return false; else return self.pick(enabledTrans).fire() ; } [Simple] operation Place modify(t : Integer) { self.itokens += t; } [Object] operation Place modify(t : Integer) { if (t>0) for (i in Sequence{1..t}) self.ctokens.add(new Token); else if (t<0) for (i in Sequence{1..-t}) self.ctokens.remove(self.ctokens.random()); }
- 22. EXTENDING TPLs 22 context PetriNet [notPriority] def: pick(s: Set(Transition)): Transition= s→any(true) [Priority] def: pick(s: Set(Transition)): Transition= s→any(t | not s→exists(t1| t1.priority>t.priority)) context Transition [not (Inhibitor or Read or Bounded)] def: enabled() : Boolean = self.ins()→forAll(tokens()>0) [Inhibitor and not (Read or Bounded)] def: enabled() : Boolean = self.ins()→forAll(tokens()>0) and self.inh→forAll(tokens()=0) [Inhibitor and Read and not Bounded] def: enabled() : Boolean = self.ins()→forAll(tokens()>0) and self.inh→forAll(tokens()=0) and self.read→forAll(p.tokens()>0) … (5 more combinations ommited) Still difficult to extend!
- 23. COMPOSING RULE BODIES OVERRIDING Override:declares precedence among rule bodies • Default (super): more specific body overrides more general body • Other semantics: subs, all 23 context PetriNet def: pick(s: Set(Transition)): Transition = s→any(true) context PetriNet [Priority] −− @Override super def: pick(s: Set(Transition)): Transition= s→any(t | not s→exists(t1| t1.priority>t.priority))
- 24. Merge operators dependingon rule signature • and/or for boolean queries, union/intersection for collections • Arithmetical operations for queries returning numbers • Sequential composition of actions for operations changing state 24 context Transition def: enabled(): Boolean = ins()→forAll(tokens()>0) COMPOSING RULE BODIES MERGE context Transition −− @Merge and [Inhibitor] def: enabled(): Boolean = inh→forAll(tokens()=0) context Transition −− @Merge and [Read] def: enabled(): Boolean = read→forAll(tokens()>0) context Transition −− @Merge and [Bounded] def: enabled(): Boolean=outs()→forAll(tokens()<bound) 4combinations insteadof8
- 25. ANALYSIS Syntactic • CMMPL andTPL well-formedness: • No binding/rule body collisions • No missing bindings/bodies • Analysing each derivable meta-model/transformation is prohibitive! • Technique: SAT solving Semantic • CMMPL Consistency • Does some derivable meta-model violate the concept invariants? • TPL contracts • Analysing each derivable meta-model/transformation is prohibitive! • Technique: Lift model finding to TPL 25
- 26. LIFTING MODEL FINDING TOPLS Model finders • Input: meta-model + OCL invariants + search bound • Output: valid instance model (or none) • USE Validator Feature explicit meta-model • Embed the feature model in the meta-model • Emulate the PCs with OCL invariants • The result is a valid model, which includes an object representing a configuration 26
- 27. ANALYSING CONSISTENCY 27 :PetriNet :Place :Transition :FMC PetriNets=true Tokens=true Simple=true Object=false Arcs=true Inhibitor=true Read=true Priority=false Bounded=false feature-explicit model itokens =-6 :ins :trans :places model configuration + :PetriNet :Place :Transition itokens = -6 :ins :trans :places extract Does some derivable meta-model violate the concept invariants? Model finder
- 28. TOOL SUPPORT Merlin: http://miso.es/tools/merlin/ •Eclipse plugin Meta-model product lines + transformation product lines Analysis based on model finding (USE Validator) • Other analyses: Sat4J • OCL syntactical correctness Independent on the transformation language • OCL (queries, analysis), can be mixed with any other language • EOL • ETL, EGL (experimental) 28
- 29.
- 30. VALIDATION RQ1: How muchspecification effort do TPLs save? Most derivable transformations are different TPL size (in LOC) considerable smaller than the total size of every transformation 30
- 31. VALIDATION RQ2: How muchanalysis effort do TPLs save? 31 • Extension of the example (256 configs) • CMMPL Consistency analysis • 20 versions, with increasing #MMs violating the invariant • Comparison with enumerative approach 10x to 120x faster if <3% MMs violate the invariant Faster than enumerative (avg) if <42% MMs violate the invariant Faster than enumerative (worst) if <90% MMs violate the invariant Only marginally slower (ms) when all MMs violate the invariant
- 32. CONCLUSIONS New notion oftransformation product lines (TPLs) • On top of meta-model product lines (MMPLs) • Coupled via concepts (abstraction mechanism) • Transformation specification (contracts) • Extensibility: composition operators • Analysis and Verification support (model finding) Tool support (Merlin) • Independent on the transformation language Experiments showing good results • TPLs are succinct, analysis is efficient TPLs as (closed) reuse mechanism 32
- 33. FUTURE WORK Apply thisnotion to other MDE artefacts: • Model-to-model transformations and code generators (already) • Editors (graphical, textual) Better support for contract analysis Lift other verification techniques, e.g., based on static analysis Testing! Refactoring for TPLs • Factor out common code to concept 33
- 34.
- 35.