Component-based design and connector synthesis (Lecture 2)

Component-based design and connector synthesis(Lecture 2)

Massimo Tivoli and Marco AutiliEmail: {massimo.tivoli, marco.autili}@univaq.it

GSSI PhD in Computer Science L’Aquila, ItalyNov 11th, 2013

Roadmap of this lecture

•By Massimo Tivoli•automatic synthesis of modular connectors via composition of protocol mediation patterns [ICSE2013]

•By Marco Autili

•automatic synthesis of service choreographies [FASE2013,SERENE2013,WCRE2013,RESS2011]

Problem and motivations

•How to achieve interoperability among heterogeneous NSs by solving protocol mismatches?

•State-of-the-art solutions•hand-coded software connectors•automatically synthesized software connectors

•Their drawbacks•connector development is a never-ending and error-

prone task•NSs interoperability depends on the interoperability of

the respective underlying technologies•not all possible protocol mismatches are solvable•current solutions produce monolithic connectors

Our solution

•A method for the automatic synthesis of modular connectors•composition of independent mediators•each mediator realizes a mediation pattern•patterns as primitive solutions to recurring protocol mismatches

•Advantages•correctness as freedom from possible mismatches•connector evolution

Preamble - Interaction Protocol Specification (IPS)

• It is an Interface Automaton (IA) slightly revised in order to account for semantically equivalent actions

• Note that the action sets of an IA must be disjoint

ba'

a

b

a

a'

Preamble - composition of two IPSs

IPS2

IPS1 IPS2

ba'

a

b

a

a'

IPS1ca

a'

c

a'

a

IPS1 || IPS2

b

c

a b c a

cinconsistency

they became hiddenin the composition

Preamble – connector algebra

• Mediator patterns ( )

• Connectors as composition of primitive mediators

aa

Cons(a)NoOp

aa

Prod(a)

ba

Trans(a,b)

ba

a1

a

Split(a,[a1,…,an])

a1

aan…

an… a1

a

Merge([a1,…,an],a)

a1

aan…

an…

a1

Order([a1,…,an],π, [a'1,…,a'n])

(π is a permutation of 1,…,n)

a1 an…

an…

…

a'π(n)…a'π(1)

a'π(1) a'π(n)

Composition Iteration

The purchase order mediation scenario

• From the Semantic Web Service (SWS) Challenge: http://sws-challenge.org/wiki/

• Two NSs implemented using different standards and protocols: the Moon Client (MC) and the Blue Service (BS)

MOONClient(MC)

Login CreateOrder SelectItem SetItemQuantity

CloseOrderConfirmItemClose PayThirdParty


PayThirdParty

Close

ConfirmItemCloseOrder

BLUEService

(BS)StartOrder AddItemToOrder GetConfirmation PlaceOrder Quit

GetConfirmation

StartOrderAddItemToOrder

AddItemToOrder

Quit

GetConfirmation

PlaceOrder

Communicationmismatches concernthe semantics andgranularity of protocolactions

http://sws-challenge.org/wiki/




<<OWLClass>>PayThirdParty

<<OWLClass>>GetConfirmation

<<OWLClass>>ConfirmItem

<<OWLClass>>PlaceOrder

<<OWLClass>>CloseOrder

<<OWLClass>>CreateOrder

<<OWLClass>>StartOrder

<<OWLClass>>Login

isPartOf{some}

isPartOf{some}<<OWLClass>>

Close

<<OWLClass>>Quit

isPartOf{some}



subsumptionprop{card}

objectProperty –ontological relation

<<OWLClass>>…

ontological concept

Domain Ontology (DO)

<<OWLClass>>AddItemToOrder

{hasPart some SelectItem, SetItemQuantity}

<<OWLClass>>SelectItem

{isPartOf some addItemToOrder}

<<OWLClass>>SetItemQuantity

{isPartOf some addItemToOrder}

isPartOf{some} isPartOf{some}

To solve communicationmismatches, it is necessaryto use ontology knowledgein order to align the twoprotocols to the sameconcepts and language





MOONClient(MC)


CloseOrderConfirmItemClose PayThirdParty


PayThirdParty

Close

ConfirmItemCloseOrder

BLUEService

(BS)StartOrder AddItemToOrder GetConfirmation PlaceOrder Quit

GetConfirmation

StartOrderAddItemToOrder

AddItemToOrder

Quit

GetConfirmation

PlaceOrder

Coordinationmismatches concernthe control structureof the protocols




11 Automatic Synthesis ofCommunication Mediators

Method overview

PP

RR

DODO Synthesis ofCommunication

Mediators

Synthesis ofCommunication

Mediators

1.11.1

WW

Wi

Wj

AutomaticSynthesis ofCoordination

Mediators

AutomaticSynthesis ofCoordination

Mediators

22

M=(||Mk)M=(||Mk)

Mx

My

AlphabetAlignmentAlphabetAlignment

1.21.2P wrapped-by WP wrapped-by W

R wrapped-by WR wrapped-by W

Automatic synthesis of communication mediators

• Synthesis of communication mediators out of subsumption relations



CloseOrder is subsumed by PlaceOrder

PlaceOrder CloseOrder x2

CloseOrder x2

M2 =

PlaceOrder

x2

x2

||






PlaceOrder CloseOrder x2

CloseOrder

M2 =

PlaceOrder






PlaceOrder CloseOrder

CloseOrder

M2 =

PlaceOrder


• Synthesis of communication mediators out of aggregation relations

CreateOrder and Login are part of StartOrder

<<OWLClass>>CreateOrder

<<OWLClass>>StartOrder

<<OWLClass>>Login

isPartOf{some}

isPartOf{some}

StartOrder

M5 =

Login

Login

CreateOrder

CreateOrder

Login

StartOrder

CreateOrder

Alphabet alignment

• When synthesized out of a subsumption (resp., aggregation) relation, a mediator is used as a wrapper for output (resp., input) actions of a protocol

StartOrder

M5 =

Login

Login

CreateOrder

CreateOrder

Login

StartOrder

CreateOrder

PlaceOrder CloseOrder

CloseOrder

M2 =

PlaceOrder

StartOrder PlaceOrder

StartOrder

PlaceOrder

P =

Alphabet of P ={StartOrder, PlaceOrder}

• P is an excerpt of the BLUE service• As second protocol, let us consider an excerpt of the MOON client

whose alphabet is {Login, CreateOrder, CloseOrder}

Alphabet alignment

• P wrapped-by M5

StartOrder? PlaceOrder!

Login?

CreateOrder?

CreateOrder?

Login?

PlaceOrder!

Login?

CreateOrder?

CreateOrder?

Login?

StartOrder?

M5 P

? denote input actions

! denote output actions

PlaceOrder? CloseOrder!M2

Alphabet alignment

• ((P wrapped-by M5) wrapped-by M2)

Alphabet of the wrapped version of P = {Login, CreateOrder, CloseOrder}

CloseOrder

Login

Login

CreateOrder

CreateOrder

Login

CloseOrder

CreateOrder

Automatic synthesis of coordination mediators

• The synthesis algorithm considers finite sets of finite traces

wrappedversion of

MC

wrappedversion of

BS

Login! CreateOrder! SelectItem! SetItemQuantity!

Clo

seO

rder?

ConfirmItem?Close! PayThirdParty?

Login? SelectItem?

ConfirmItem! CloseOrder! Close?

ConfirmItem!

CreateOrder? SetItemQuantity?SelectItem?

SetItemQuantity?


• In particular, it considers pairs of semantically-related traces

wrappedversion of

MC

wrappedversion of

BS

Login! CreateOrder! SelectItem! SetItemQuantity!

Clo

seO

rder?

ConfirmItem?Close! PayThirdParty?

Login? SelectItem?

ConfirmItem! CloseOrder! Close?

ConfirmItem!

CreateOrder? SetItemQuantity?SelectItem?

SetItemQuantity?

strong notion => possible under-use of protocols


• For each pair of semantically-related traces, compute the difference pairC

lose

Ord

er?

ConfirmItem?PayThirdParty?

wrappedversion of

MCLogin! CreateOrder! SelectItem! SetItemQuantity!

Close!

ConfirmItem! CloseOrder!

ConfirmItem!

SelectItem?

SetItemQuantity?wrappedversion of

BSLogin? SelectItem?

Close?

CreateOrder? SetItemQuantity?


Clo

seO

rder?



ConfirmItem!

SelectItem?

SetItemQuantity?

since (i) the original traceswere semantically-related,(ii) possible hidden actions havebeen removed, and (iii) loop/cyclesare considered k times, these tracescan differ for three reasons only


Clo

seO

rder?



ConfirmItem!

SelectItem?

SetItemQuantity?1) unshared actions

[| Trans(PayThirdParty,PayThirdParty’

)* |]



Clo

seO

rder?



ConfirmItem!

SelectItem?

SetItemQuantity? 2) extra/missing sends correspondingto redundant messages

[| Prod(SetItemQuantity)* |][| Prod(SelectItem)* |]

[| Cons(ConfirmItem)* |]



Clo

seO

rder?



ConfirmItem!

SelectItem?

SetItemQuantity? 3) complementary shared actions thatappear in a different order

[| Order([ConfirmItem,CloseOrder],(2,1),

[ConfirmItem’,CloseOrder’])* |]


Correctness and connector evolution

•M enjoys the same correctness properties of a monolithic connector obtained via quotient•M||(R wrapped-by W) refines Inv((P wrapped-by W))•M||(P wrapped-by W) refines Inv((R wrapped-by W))

•Relevant changes can be applied on M by simply acting on its constituent mediators, without entirely re-synthesizing its protocol• the most interesting scenario is related to changes at the

level of the protocol ontology-> syntactic changes correspond to simple relabeling-> protocol-level changes imply to re-iter the synthesis on the affected traces only

Related work

• Formal approaches to protocol conversion [Calvert, Lam 1990 & Lam 1998]

• Specification of protocol adapters [Yellin, Strom 1997]• they do not support reordering (Order primitive) and different granularity

of protocol languages (Split and Merge primitives)

• Automatic mediation of business processes [Vaculin et al. 2007 & 2008]• due to the lack of a formal characterization, it is difficult to assess

respective advantages and disadvantages

• Connector wrappers as protocol transformations [Garlan et al. 2003]• Algebra of stateless connectors [Bruni, Lanese, Montanari 2006]

• they support modularity• the focus is on connector design and specification => no automation

• Converter synthesis [Passerone et al. 2002]• they assume an “inconsistency-free” specification of the converter• in the practice, providing such a specification is not a trivial task

• Generation of component adapters [Canal, Poizat, Salaün 2008]• it requires to know many implementation details about the adaptation

Roadmap of this lecture

•By Massimo Tivoli•automatic synthesis of modular connectors via

composition of protocol mediation patterns [ICSE2013] •By Marco Autili

•automatic synthesis of service choreographies [FASE2013,SERENE2013,WCRE2013,RESS2011]

Component-based design and connector synthesis(Lecture 2)

Thank you for your attention!

Any questions?

GSSI PhD in Computer Science L’Aquila, ItalyNov 11th, 2013

Massimo Tivoli and Marco AutiliEmail: [email protected]

Bibliography

• [ICSE2013] M. Tivoli and P. Inverardi, Automatic Synthesis of Modular Connectors via Composition of Protocol Mediation Patterns, in: ICSE, 2013

• [FASE2013] M. Autili, D. Di Ruscio, A. Di Salle, P. Inverardi and M. Tivoli, A model-based synthesis process for choreography realizability enforcement, in: FASE, pages 37-52, 2013

• [SERENE2013] M. Autili, A. Di Salle and M.Tivoli, Synthesis of resilient choreographies, in: SERENE, pages 94-108, 2013

• [WCRE2013] M. Autili, P. Inverardi, and M. Tivoli, CHOReOS: Large Scale Choreographies for the Future Internet, in: WCRE, 2013

• [RESS2011] M. Autili, D. Di Ruscio, P. Inverardi, J. Lockerbie and M. Tivoli, A Development Process for Requirements Based Service Choreography, in: RESS, 2011

Documents

Component-based design and connector synthesis (Lecture 2)