Middleware-layer Connector Synthesis:

Beyond State of the Art in Middleware Interoperability

Valérie Issarny, INRIA

Joint work with A. Bennaceur, D. Bromberg

And colleagues from FP7 ICT FET CONNECT project

Composing Systems inToday’s Pervasive Networks

1. Discovery protocol interoperability

2. Interaction protocol interoperability

3. Data interoperability

4. Application interoperability

5. Interoperability of non-functional properties

2

The Simple Yet Challenging Photo Sharing Scenario

Any peer around?How may I get the picture?Is it a jpg file?May I get all the related pictures?Am I allowed to forward those pictures?

See Lecture by Gordon Blair onInteroperability in Complex Distributed Systems

Mediation to Make Systems Interoperable

3

P2P Photo Sharing C/S-based Producer

See Lecture by Paola Inverardi onApplication-layer Connector Synthesis

Mediation that actually bridges the Application (Different protocols for accessing photo files)

&Middleware (Different interaction paradigms)

Layers

Mediation Must Span All Layers

4

Constituent systems heterogeneity in coordination models, communication protocols, data representation models (middleware platforms)

Most common coordination models: client/server, pub/sub, tuple space

Yet Another Scenario: Search & Rescue Operations

See Lecture by Nikolaos Georgantas onCONNECT Architecture

Outline

Middleware-based connectors Formalizing middleware-based connectors Revisiting interoperability connectors Emergent connector synthesis Emergent connector in practice Conclusion

8

Middleware-based Connector

10

HeterogeneousMiddleware

Built-in Mediation

Discovery &Routing

Supporting Middleware

NFPEnforcement

See R. N. Taylor et al. Software Architecture: Foundations, Theory & Practice - Wiley

Connecting Systems

12

Classifying Connection Mismatches

13

Application Mismatches

14

Middleware Mismatches

15

Mediation Connector

16

The Many Facets of Mediation

17

How to make mediation connector emergent?

Towards Emergent Connectors

Formalizing middleware-based connectors to reason about interoperability

Revisiting existing interoperability connectors

Emergent connector synthesis

18

Outline

Middleware-based connectors Formalizing middleware-based connectors Revisiting interoperability connectors Emergent connector synthesis Emergent connector in practice Conclusion

19

Finite State Processes

20

END Predefined process, successfull terminationset S Denotes a set of action labels[i : S] Binds the variable i to a value from S

Primitive Processes (P)a -> P Action prefixa -> P | b -> P ChoiceP;Q Sequential compositionP(X =‘ a) Parameterized process: P is described using parameter X

and modeled for a particular parameter value, P(a)P/{new_1/old_1, …, new_n/old_n}

RelabelingP \{a1, a2, …, an} HidingP +{a1, a2, …, an} Alphabet extension

Composite Processes (||P)P||Q Parallel compositionforall [i : 1..n] P(i) Replicator construct: equivalent to the parallel compositiona : P Process labeling

SOAP-based Middleware Connector

21

Role ClientSOAP = SOAP-RPCCall -> SOAP-RPCReceiveReply -> ClientSOAP

Role ServerSOAP = SOAP-RPCReceiveCall -> SOAP-RPCReply -> ServerSOAP

GlueSOAP = SOAP-RPCCall -> SOAP-RPCReceiveCall -> GlueSOAP | SOAP-RPCReply -> SOAP-RPCReceiveReply -> GlueSOAP

||ConnectorSOAP = ClientSOAP || GlueSOAP || ServerSOAP

SOAP

See Work by D. Garlan et al. at CMU

Photo Sharing over SOAP - Application -

set SOAP_PhotoSharing_Actions =

{uploadPhoto, searchPhoto, downloadPhoto, downloadComment, commentPhoto}

PhotoSharingConsumer = (req.searchPhoto -> P1),

P1 = (req.downloadPhoto ->P1 | req.commentPhoto -> P1)

|req.downloadComment -> P1 | terminate -> END).

PhotoSharingProducer =

(req.uploadPhoto -> PhotoSharingProducer | terminate -> END).

PhotoSharingServer =

(prov.uploadPhoto -> PhotoSharingServer

|prov.searchPhoto -> PhotoSharingServer

|prov.downloadPhoto -> PhotoSharingServer

|prov.commentPhoto -> PhotoSharingServer

|prov.downloadComment -> PhotoSharingServer | terminate -> END).

22

Photo Sharing over SOAP - SOAP Middleware -

ClientSOAP (X =’ op) =

(req.[X] -> P1 | terminate -> END),

P1 = (SOAP-RPCCall[X] ->SOAP-RPCReceiveReply[X] -> ClientSOAP ).

ServerSOAP (X =’ op) =

(prov.[X] -> P2 | terminate -> END),

P2 = (SOAP-RPCReceiveCall[X] -> SOAP-RPCReply[X] -> ServerSOAP ).

GlueSOAP (X =’ op) =

(SOAP-RPCCall[X] -> P0 | terminate -> END),

P0 = (SOAP-RPCReceiveCall[X] -> SOAP-RPCReply[X]

-> SOAP-RPCReceiveReply[X] -> GlueSOAP ).

23

Photo Sharing over SOAP - Photo Sharing System -

||SOAP_PhotoSharing =

(PhotoSharingProducer

|| PhotoSharingConsumer

|| PhotoSharingServer

|| (forall [op:SOAP_PhotoSharing_Actions] ServerSOAP (op))

|| (forall [op:SOAP_PhotoSharing_Actions] ClientSOAP (op))

|| (forall [op:SOAP_PhotoSharing_Actions] GlueSOAP (op))).

24

Outline

Middleware-based connectors Formalizing middleware-based connectors Revisiting interoperability connectors Emergent connector synthesis Emergent connector in practice Conclusion

25

Approaches to Interoperability

Solutions applicable to Middleware and Application layers• Software Bridges• Interoperability Platforms• Transparent Interoperability

26See Lecture by Gordon Blair & Massimo Paolucci on

Interoperability in Complex Distributed Systems

Software Bridges

27

LegacyApplication

Legacy Middleware

A

Peer

Legacy Application

Legacy Middleware

B

Peer

Bridge A to B

3rd Party Peer

E.g.:OrbixCOMet, SOAP2CORBA at middleware-layer

Domain-specific bridges –MSN-Yahoo bridge - at application-layer

Bridge Mediator

28

||Direct_Bridge_Mediator = (Bridge || T)

Bridging Connector

Legacy connectors

Role R1i,i in [1..2] = Role R1 of Connectori

Role R2i,i in [1..2] = Role R2 of Connectori

Gluei,i in [1..2] = Glue of Connectori

set Ii,i in [1..2] = Set of events initiated from Role R1i and R2i

Bridge = tag1.[e1:I1] -> tag2.[e1] -> Bridge

| tag2.[e2:I2] -> tag1.[e2] -> Bridge

Adaptation process

T = Required transformations of (tagi.ej)s to bridge Connector1 to Connector2

Direct bridge connector

||C-DBridge = R11 || tag1:Glue1 || Bridge || T || tag2:Glue2 ||R22

29

Indirect Bridge Mediator

30

||Indirect_Bridge_Mediator = (T1 || Bridge1 || Bridge2 || T2)

E.g., ESB solutions (Artix, PetalS, …), Interoperability manager (MUSDAC)Domain-specific J-EAI for interoperable IMs

ESB Connector

Bus

Role R1bus = Role R1 of Connectorbus

Role R2bus = Role R2 of Connectorbus

Gluebus = Interactions between Role R1bus and Role R2bus

Legacy connectors

Role R1 = |i=1..n (a.gluei -> R1i),

R1i, i=1..n = (R1i initial specification as given by Connectori) | reset -> R1

Role R2 = |k=1..m (a.glue’k -> R2k),

R2k, k=1..m = (R2k initial specification as given by Connector’k) | reset -> R2

Glue i=1..n = Interactions between R1i and R2i

Glue’ k=1..m = Interactions between R’1k and R’2k

Events

set I1i, i=1..n (O1i, i=1..n ) Set of events initiated (observed) from Role R1i

set I2k, k=1..m (O2k, k=1..m ) Set of events initiated (observed) from Role R2k

31

R1 R2

ESB Connector (2)

Adaptation process

T1 = |i=1..n (a.gluei -> ToTi),

ToT i=1..n = Required transformations to bridge Connectori to Connectorbus | a.reset -> T1

T2 = |k=1..m (b.glue’k -> ToT’k),

ToT’k, k=1..m = Required transformations to bridge Connectorbus to Connector’k | b.reset -> T2

Bridging processes

Bridge1 = |i=1..n (a.gluei -> Bridgei),

Bridgei=1..n = [e : I1i] -> a.tagi.[e] -> Bridgei | a.tagi.[e : O1i] -> [e] -> Bridgei

| a.reset -> Bridge1

Bridge2 = |k=1..m (b.glue’k -> Bridge’k),

Bridge’k=1..m = [e : I2k] -> b.tagk.[e] -> Bridge’k|b.tagk.[e : O2k] -> [e] -> Bridge’k

|b.reset -> Bridge2

Indirect bridge connector||C-IBridge = R1 || T1 ||i=1..n a.tagi:Gluei || Bridge1|| Gluebus || Bridge2 ||k=1..m b.tagk:Glue’k || T2 || R2

32

T1 T2

Software Bridges Assessment

33

• Handcoded development of bridges (i.e., Process T)• Direct bridging does not scale • Interoperability limited to the behavior of the intermediary in

the case of indirect bridging

Interoperability Platforms

34

Application

Peer

ApplicationLegacy

Middleware

Peer

Substituted Middleware

Translation

Interoperability Platform

E.g.: UIC, ReMMoC at middleware-layer

Domain-specific platform – IM Pidgin, Adium - at application-layer

Interoperability Mediator

35

||Interoperability_Mediator = (Switch || Bridge || T)

Interoperability Connector (1)

Proprietary interface

Role Rinterface = Bridge interface

Role R2 = |i=1..n (gluei -> R2i),

R2i,i in [1..n] = Inititial spec of Role R2 of Connectori | reset -> R2

Gluei,i in [1..n] = Glue of Connectori

Initiated and observed events

set I2 (O2)i,i in [1..n] = Set of events initiated (observed) from Role R2i

set I (O) interface = Set of events initiated (observed) from Role Rinterface

Switch process

Switch = (election -> reset -> Switch |i=1..n election -> gluei -> Switch)\{election}

36

Interoperability Connector (2)

Adaptation process

T = |i=1..n (gluei -> ToTi),

ToT i=1..n = Required transformations to bridge Rinterface to Connectori | reset -> T

Bridging process

Bridge = |i=1..n (gluei -> Bridgei),

Bridgei, i in [1..n] = [e : Rinterface] -> tagi:[e] -> Bridgei | tagi:[e :Ointerface] -> [e]-> Bridgei

| [e : I2i] -> tagi:[e] -> Bridgei | tagi.[e :O2i] -> [e]-> Bridgei

| reset -> Bridge

Interoperability platform connector

||C-InteropPlatforms = Rinterface || Switch || T || Bridge ||i=1..n tagi :Gluei || R2

37

Interoperability Platform Assessment

38

• Proprietary interface and behavior

Transparent Interoperability

3939

LegacyApplication

Legacy Middleware

Peer

Legacy Application

Legacy Middleware

Peer

Translation to

Intermediary

3rd Party Peer

Translation to

Intermediary

E.g.:INDISS, ubiSOAP at middleware layer

Domain-specific interoperability – IM CrossTalk – at application layer

Transparent Mediator

40

||Transparent_Mediator = (Switch || W1 || M1 || Bridge1 || Bridge2 || M2 || W2 || Switch’)

Transparent Interoperability Connector (1)Legacy connectors

Role R1 = |i=1..n (a.gluei -> R1i),

R1i,i in [1..n] = Inititial spec of Role R1i of Connectori | reset -> R1

Role R2 = |k=1..m (b.gluek -> R2k),

R2k,k in [1..m] = Inititial spec of Role R2 of Connector’k | reset -> R2

Gluei,i in [1..n] = Interactions between R1i and R2i

Glue’k,k in [1..m] = Interactions between R’1k and R’2k

Initiated and observed events

set I2 (O2)i,i in [1..n] = Set of events initiated (observed) from Role R1i

set I2 (O2)k, k in [1..m] = Set of events initiated (observed) from Role R’2k

set Ei, i in [1..n] (Ek, k in [1..m]) = aR1i ∩ aGluei (aR2k ∩ aGlue’k)

Set S E1n (S E2m)= Ui=1..n E1i (Uk=1..m E2k)

Set S O1n (S O2m)= Ui=1..n O1i (Uk=1..m O2k)41

TransparentInteroperability Connector (2)Switch processes

Switch = (a.election -> a.reset -> Switch |i=1..n a.election -> a.gluei -> Switch)\{a.election}

Switch’ = (b.election->b.reset->Switch’ |k=1..m b.election ->b.glue’k ->Switch’)\{b.election}

Image protocol generation

W1 = |i=1..n (a.gluei -> ToGluei),

ToGluei=1..n = [e : I1i]->a.tagi:[e]->ToGluei | a.tagi:[e :O1i] -> [e]-> ToGluei | a.reset -> W1

W2 = |k=1..m (b.glue’k -> ToGlue’k),

ToGlue’k=1..m = [e : I2k->b.tagk:[e]->ToGlue’k | b.tagk:[e :O2k]-> [e]->ToGlue’k| b.reset->W2

M1 = |i=1..n (a.gluei -> ToMapi),

ToMapi=1..n = a.tagi.[e : I1i]->a.tagi.f(e)->ToMapi

| a.tagi.f(e:SO1n) -> a.tagi.[e : O1i]-> -> ToMapi | a.reset -> M1

M2 = |k=1..m (b.glue’k -> ToMap’k),

ToMap’k=1..m = b.tagk.[e : I2k]->b.tagk.f(e)->ToMap’k

| b.tagk.f(e:SO2m) -> b.tagk.[e : O2k]-> -> ToMap’k| b.reset -> M2

42

TransparentInteroperability Connector (3)Bridging process

Bridge1 = |i=1..n (a.gluei -> ToBridgei),

ToBridgei, i in [1..n] = a.tagi.f(e2:SE2m) -> f(e2) -> ToBridgei

| f(e1:SE1n) -> a.tagi.f(e2) -> ToBridgei

| a.reset -> Bridge1

Bridge2 = |k=1..m (b.glue’k -> ToBridge’k),

ToBridge’k, k in [1..m] = b.tagk.f(e1:SE1n) -> f(e1) -> ToBridge’k| f(e2:SE2m) -> b.tagk.f(e2) -> ToBridge’k| b.reset -> Bridge2

Transparent interoperability connector

||C-Transparent_Interop

= R1 || Switch ||i=1..n a.tagi:Gluei/{f(r:aGluei)/[r]} || W1 || M1 || Bridge1

|| M2 || W2 ||k=1..m b.tagk:Gluek/{f(r:aGlue’k)/[r]} || Switch’ || R2

43

Transparent Interoperability Assessment

44

• Addresses interoperability at a single layer• Projection function f to be given, making it similar to indirect

bridging although with (design-time) adaptive buses• Does not account for the heterogeneity of interaction paradigms

Outline

Middleware-based connectors Formalizing middleware-based connectors Revisiting interoperability connectors Emergent connector synthesis Emergent connector in practice Conclusion

45

The CONNECT Approach to Interoperability: Emergent Middleware

Synthesize CONNECTors between heterogeneous Networked Systems (NS)• Generate middleware and

application protocols to create connections that will overcome the interoperability barrier

• CONNECTors devised and created at Run Time

• Minimal a priori knowledge/ assumptions

4646

NSCONNECTor

NS« Mediation » connectoraka Emergent middleware

See Lecture by Nikolaos Georgantas & Paul Grace onThe CONNECT Architecture

Meeting in the Heterogeneous World

47

OPhoto

OSOAP

P

Networked systems meet according to matching “Affordances”

QOPhoto

OLime

Photo sharing using SOAP

Photo sharing using LIME

“Affordance” behaviour is characterized by its protocol and related ontology

from application down to middleware layer

Photo sharing Photo sharing

“Affordance” behaviour is characterized by its protocol and related ontology

Networked System Model forOn-the-fly Connection

Interface definition leveraging Semantic Web service technologies• Affordance aka Capability

<Type, Concept, Inputs, Outputs>

• Interface signature• Action defined as <Mdw, Application, I, O>

• Affordance behavior

48

P2P Photo Sharing Interface

Interfacephoto_sharing = {< Out, PhotoMetadata, , < photoMetadata >>,

< Out, PhotoFile, , < photoFile >>,

< Rdg, PhotoMetadata,< photoMetadata >, < photoMetadataList >>,

< Rd, PhotoFile, < photoID >, < photoFile >>,

< Rd, PhotoComment, < photoID >, < photoComment >>,

< Out, PhotoComment, , < photoComment >>,

< In, PhotoComment, < photoID >, < photoComment >>,

< Rd, PhotoComment, < photoID >, < photoComment >>

}

49

P2P Photo Sharing Protocol Application Layer

set Lime_PhotoSharing_Actions = {photoMetadata, photoFile, photoComment}

PhotoSharingPeer = (req.photoMetadata -> Consumer

| prov.photoMetadata -> Producer),

Producer = (prov.photoFile -> PhotoSharingPeer),

Consumer = (req.photoFile ->Consumer

| req.photoComment -> Consumer

| prov.photoComment -> Consumer

| req.photoFile -> PhotoSharingPeer

| req.photoComment -> PhotoSharingPeer

| prov.photoComment -> PhotoSharingPeer

| terminate -> END)

50

P2P Photo Sharing ProtocolMiddleware Layer

Lime_Reader(X =‘ tuple) = (req.[X] -> P1),

P1 = (rd[X] -> Lime_Reader | rdp[X] -> Lime_Reader | rdg[X] -> Lime_Reader

| in[X] -> Lime_Reader | inp[X] -> Lime_Reader | ing[X] -> Lime_Reader

| terminate -> END).

Lime_Writer(X =‘ tuple) = (prov.[X] -> P2),

P2 = (out[X] -> Lime_Writer | outp[X] -> Lime_Writer

| outg[X] -> Lime_Writer | terminate -> END).

Lime_glue(X =‘ tuple) = (write[X] -> P0 | outp[X] -> P0 | outg[X] ->P0

| terminate -> END),

P0 = (rd[X] -> P0 | rdp[X] -> P0 | rdg[X] -> P0

| in[X] -> Lime_glue | inp[X] -> Lime_glue | ing[X] -> Lime_glue).

51

P2P Photo Sharing ProtocolPhoto Sharing System

const NumberOfPeers = 2

||Lime_PhotoSharing =

( [i : 1..NumberOfPeers]:PhotoSharingPeer

|| (forall [tuple:Lime_PhotoSharing_Actions] Lime_Writer(tuple))

|| (forall [tuple:Lime_PhotoSharing_Actions] Lime_Reader(tuple))

|| (forall [tuple:Lime_PhotoSharing_Actions] Lime_glue(tuple))).

52

Talking the Same LanguageThe Key Role of Ontology

53

P’ Q’

Q

TranslatedProtocols

OPhotoOPhoto

AlignedOntology

Interoperate?

OSOAP

OPhoto

OLime

OPhoto

OMW

OPhoto

OMW

Translation

POMW

Behavioralmatchmaking

?

The Photo Sharing Ontology

54

Classified according to subsumption relationships

Reasoning about Mediated Matching

Equivalence of LTS traces as the basis

55

Behavioral matchmaking under:mapping of semantic-based actions

But must account for application-layer interactions using middleware

Leveraging the rich SOTA on protocol conversion/mediation

See Lecture by Paola Inverardi onApplication-layer Connector Synthesis

Need to Abstract Middleware Protocols

Towards aligning middleware functions• 4 main middleware types

• RPC• Shared memory• Event-based• Message-based

56

RPC Middleware

57

Shared Memory Middleware

58

Event-based Middleware

59

Message-based Middleware

60

Semantics of Middleware Functions

61

From Lime to Shared Memory P2P Photo Sharing to…

Reader(X =‘ data) = (req.[X] -> P1),

P1 = (read[X] -> Reader | terminate -> END).

Writer(X =‘ data) = (prov.[X] -> P2),

P2 = (write[X] -> Writer | terminate -> END).

SM_glue(X =‘ data) = (write[X] -> P3 | terminate->END),

P3 = (read[X] -> SM_glue).

62

Shared Memory P2P Photo Sharing (LTS)

63

<Write, PhotoMetadata, , photoMetadata>

<Write, PhotoFile, , photoFile>

<Read, PhotoFile, photoID, photoFile>

<Read, PhotoMetadata, photoMetadata, photoMetadataList>

<Write, PhotoComment, , photoComment>

<Read, PhotoComment, photoID, photoComment>

… to Middleware AgnosticP2P Photo Sharing

Reader(X =‘ data) = (req.[X] -> P1),

P1 = (input[X] -> Reader | terminate -> END).

Writer(X =‘ data) = (prov.[X] -> P2),

P2 = (output[X] -> Writer | terminate -> END).

SM_glue(X =‘ data) =

(output[X] -> P | terminate -> END),

P = (input[X] -> SM_glue).

64

Middleware AgnosticP2P Photo Sharing (LTS)

65

<PhotoMetadata, , photoMetadata>

<PhotoFile, , photoFile>

<PhotoFile, photoID, photoFile>

<PhotoComment, , photoComment >

<PhotoComment, photoID, photoComment>

Middleware AgnosticC/S Photo Sharing (LTS)

66

Consumer

<SearchPhotos, photoMetadata, photoMetadataList>

<DownloadPhoto, photoID, photoFile>

<CommentPhoto, photoComment, acknowledgement >

Interoperable Systems atAbstract Level

67

<PhotoMetadata, , photoMetadata>

<PhotoFile, , photoFile>

<PhotoFile, photoID, photoFile>

<PhotoComment, , photoComment >

<PhotoComment, photoID, photoComment><SearchPhotos, photoMetadata, photoMetadataList>

<DownloadPhoto, photoID, photoFile>

<CommentPhoto, photoComment, acknowledgement >

Emergent Connectors Synthesis

Affordance matching according to subsumption relationships between concepts of the affordances

Interface mapping among the actions of the protocols to be made interoperable for the following mismatches• Splitting of input actions / Merging of output actions • Extra output actions

Verifying whether protocols may successfully coordinate according to the computed interface mapping

→Mediation connector that implements the computed interface mapping + message translation

68

Interface Mapping

MapI(IA1, IA2) = <a, I, O>IA1 {<a, I, O> → map(<a, I, O>, IA2)}

<a’, I’, O’>IA2 {<a’, I’, O’> → map(<a’, I’, O’>, IA1)}

with:

map(<a, Ia, Oa>, I) = {<<out.bi, Ii, Oi> I>i=1..n |

a i {bi}

^ Ii ≤ n (j<i {Oi}) {Ia}

^ Oa (j<i {Oi}) {Ia}

}

and:seq1 map(<a, Ia, Oa>, I), seq2 map(<a, Ia, Oa>, I) | seq2 < seq1

69

Mediator Synthesis

Adaptation processes:

Ma = (||i Processes that merge/split A1 actions)

Ma’ = (||i’ Processes that merge/split A2 actions)

Mb’ = (||i Processes that consume extra output actions of A2)

Mb = (||i Processes that consume extra output actions of A1)

Behavioral matching under mediation:

P1 || Ma || Mb’ ≤ P2 || Ma’ || Mb

where A1 A2 and A1 req A2

Emergent connector:

Ma || Mb’ || Ma’ || Mb

70

From Abstract to Concrete Emergent Connectors

71See Lecture by Nikolaos Georgantas & Paul Grace on

The CONNECT Architecture

Appraches to Middleware Synthesis

72

Still a long way to go…

Outline

Middleware-based connectors Formalizing middleware-based connectors Revisiting interoperability connectors Emergent connector synthesis Emergent connector in practice Conclusion

73

The Instant Messaging Case Study

74

XMPP System

XMPP Client XMPP ClientXMPP

MSNP SystemMSN Client MSN Client

MSNP

• 1-1 Interface mapping• Behavioral matching using OFSP

(FSP enriched with ontology reasoning over actions)

Making IMs interoperable

Software bridges• Direct: MSN & Yahoo!Messenger• Indirect: J-EAI

Interoperability platforms• Pidgin, Adium

Transparent interoperability• CrossTalk

75

The CONNECT Way

76

XMPPMSNP

XMPPOFSP process

MSNPOFSP process

Behavioral Matching

IM Ontology(OWL)

Adaptation

Mediator

OFSP Modeling

Failure

Exact matching

Partial matchingNo matching

Ontology-based Model Checking

Mediation

Dealing with Infrastructure-based functionalities

abdc

e

The IM Ontology

77

OFSP Specification of MSNP

MSNClient =

(<input, MSNAuthenticationRequest, {UserID}, {Challenge} >

-> < input, MSNAuthenticationResponse, {Response}, {Authenticationok} >

-> ExchangeMsgs).

ExchangeMsgs =

(< input, CreateChatRoom, {UserID}, {ConversationID} >

-> < input, JoinChatRoom, {UserID}, {Acceptance} -> P1

| < output, JoinChatRoom, {UserID}, {Acceptance} >

-> < input, {ChatRoomInfo, , {ConversationID} > -> P1

P1 =

(< input, InstantMessage, {UserID, ConversationID, Messageg}, > -> P1

| < output, InstantMessage, {UserID, ConversationID, Message}, > -> P1

| < input, MSNLogout, {UserID }, > -> END

78

OFSP Specification of XMPP

79

XMPPClient =

(< input, XMPPAuthenticationRequest, {UserID}, {Challenge} >

-> < input, XMPPAuthenticationResponse, {Response}, {Authenticationok}> -> ExchangeMsgs).

ExchangeMsgs =

(< input, InstantMessage, {SenderID, RecepientID, Message}, > -> ExchangeMsgs

| < output, InstantMessage, {SenderID, RecipientID, Message <}, > -> ExchangeMsgs

| < input, XMPPLogout, {UserID}, > -> END).

OFSP Specification MSNP-XMPP Mediator

80

Map1 =

(<output, InstantMessage, {SenderID, RecepientID, Message} , >-> <input, InstantMessage,{UserID, ConversationID, Message } , >-> Map1).

Map2 =

(<output, InstantMessage, {UserID, ConversationID, Message } , >-> <input, InstantMessage, {SenderID, RecepientID, Message}, >-> Map2).

||Mediator = (Map1 || Map2).

On-line Mediation

81

Parser

Composer

Operation1

Inputs1

Outputs1

input

Parser

ComposerTransform

Operation2

Inputs2

Outputs2

output

InstantMessage

senderID, recepientIDmessage∅

input

InstantMessage

userID, conversationIDmessage∅

input

Mediator

Message Mediation

82

UUM 15 amel.bennaceur1@yahoo.com 32 1 159MIME-Version: 1.0Content-Type: text/plain; charset=UTF-8X-MMS-IM-Format: FN=Segoe%20UI; EF=; CO=0; CS=1; PF=0Dest-Agent: client

Test Message from MSN to XMPP

<?xml version="1.0" encoding="UTF-8"?><Thing><Version>17</Version><IM>?0</IM><Service>6</Service><PacketLength>142</PacketLength><MSNP>YMSG</MSNP><Status>1515563606</Status><Sender>amel.bennaceur1</Sender><Recipient>bennaceur_amel@hotmail.com</Recipient><SessionID>5684388</SessionID><VendorID>0</VendorID></Thing>

<ObjectPropertyIRI="#consistsOf"/><NamedIndividual IRI="#first"/><NamedIndividual IRI=“MSN"/><DataPropertyIRI="#hasSender"/><NamedIndividual IRI="#first"/><Literal abbreviatedIRI="xsd:string">amel.bennaceur1</Literal></DataPropertyAssertion><DataPropertyAssertion><DataPropertyIRI="#hasRecipient"/><NamedIndividual IRI="#first"/><Literal abbreviatedIRI="xsd:string">bennaceur_amel@hotmail.com</Literal></DataPropertyAssertion>

…

<?xml version="1.0" encoding="UTF-8"?><message

from=‘bennaceur_amel@hotmail.com' id='ktx72v49' to=‘amel@example.net' type='chat' xml:lang='en'>

<body>Test Message from MSN to XMPP</body> </message>

<ObjectPropertyIRI="#consistsOf"/><NamedIndividual IRI="#first"/><NamedIndividual IRI=“XMPP"/><DataPropertyIRI="#hasSender"/><NamedIndividual IRI="#first"/><Literal abbreviatedIRI="xsd:string"> bennaceur_amel@hotmail.com </Literal></DataPropertyAssertion><DataPropertyAssertion><DataPropertyIRI="#hasRecipient"/><NamedIndividual IRI="#first"/><Literal abbreviatedIRI="xsd:string“> amel@example.net </Literal></DataPropertyAssertion>

…

DSL parser

XSLT engine

Reasoning

XSLT engine

XML Composer

Instant MessagingOntology

MSNP DSL Specs

MSNP OWL individual

MSNP XML Message

MSNP text message

XMPP OWL individual

XMPP Message

Performance EvaluationProprietary vs Synthesized Mediator

Latency (ms)

Native Hand Synthesized

Pars Trans

MSNP - MSNP 22 12 231 11

YMSG - YMSG 24 08 342 12

YMSG - MSNP 35 06 234 20

MSNP - XMPP N/A 52 135 07

YMSG - XMPP N/A 44 145 06

MSNP - GTalk N/A 65 N/A

YMSG - GTalk N/A 78 N/A

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Performance EvaluationProprietary vs Synthesized Mediator

Lines of Code/Spec

Hand-coded Synthesized

Pars Trans

YMSG - MSNP 1172 245

MSNP - XMPP 0750 203

YMSG - XMPP 0945 144

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On the fly IM Interoperability in Action

Demo by Amel Bennaceur

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Outline

Middleware-based connectors Formalizing middleware-based connectors Revisiting interoperability connectors Emergent connector synthesis Emergent connector in practice Conclusion

87

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Composing Pervasive Systems

State-of-the art survey in middleware & data interoperability shows that no current approach meets today’s interoperability challenge

Need for emergent middleware where connectors are synthesized on the fly

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Synthesizing CONNECTors for Pervasive Systems

• CONNECTors implementing emergent middleware that mediate interactions among pervasive networked systems

• Formalization of interoperability based on matching and mapping relationships between interaction protocols run by networked systems

• Dealing with application- and middleware-layer connectors

• Further challenge of enforcing non-functional properties

Thank you and

Thanks to CONNECT colleagues(A. Bennaceur, G. Blair, N. Georgantas, P. Grace, P.

Inverardi, R. Saadi, R. Spalazzese, …)