Specifying and Verifying Web Service

lemoncolonyΑσφάλεια

3 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

100 εμφανίσεις

Ahmed
Bataineh

Sadeq

Bani

Mellhem

Specifying and Verifying Web Service
Composition


1

OUTLINES ……………………….


SOA service oriented architecture


Main blocks


Main principles


Discussion



Web service definition


Service definition


Web service VS web application



How does the web service work


Web service architecture


UDDI


WSDL


SOAP



2

OUTLINES ……………………….



Web service composition


Web service composition definition


Orchestration model / work flow


Formal approaches to web service composition


AI planning


Process Algebra


Temporal logic





3

Calss

A

{


f1 ()


{


Int

a;



f2(a);


}

}

Calss

B

{


f2 (
int
)


{….}

}

Software application


Communicates together

Calss

A

{


f1 ()


{


Int

a;



f2(a);


}

}

PC1

Calss

B

{


f2 (
int
)


{….}

}

PC2

JAVA

C++

-

Service
loose coupling

-

SOA

Introduction …

4

SOA service oriented architecture


SOA
stands for service oriented architecture
,




interoperable
services
form.




Service
loose coupling



Service discoverability




Common Communication language



Service reusability



SOA
main building Blocks



1
-

service provider


2
-

service requester


3
-

service registry



5

Figure1 :
Service oriented architecture









Web services Definition



Service :
-

an example book a ticket , on line
banking ..



Web service is a self
-
describing
software
model



Web application
has GUI to the end user.




Web services :
-

it doesn’t have GUI to the
end user , it was designed to be used by other
software application.

6

Fig 2 : purchase
application involving
interacting web services


How does the web service work


Main steps



1
-

discovering the web services


-

UDDI uses
Registries and APIs to Publish, Discover
and
Describing
the web services



2
-

description of the web services


-

WSDL
describes the web services in terms of its operations
and its messages



-

WSDL
is extensible and neutral


3
-

invocation the web services


-

SOAP
is standard for simple object protocol


-

Stub
-
code
a piece of software that generates the

SOAP
request and generate the SOAP
response.



-

stub
-
code
is mainly responsible to parsing the XML Format
.




7

Fig3 : web service Architecture

web
service
composition definition



Web service composition
definition



Business process
definition
(
workflow systems to
manage
)

8

Figure 4 : travel system

orchestration
model


Orchestration model/
coordination
model


9

Figure 5 : BPEL WS invoking WS

Execution monitoring


Centralized execution



Distributed execution

10

Raised Problem


Verification and validation have to be
dynamically
applied at
the run time after finishing the design time.

11

AI planning


-

the task of coming up
with sequence of actions
that
will achieve
a
goal


S0

S1

S2

S3

Formal description for
the specification of web
service composition
system using situation
calculus

Converting the
Formal formula
to programming
constructs

If …. Then …

Else … End if


For …. Loop

End loop

S0

S1

S2

S3

a0

a1

a2

a3

a0

a4

a1

a2

12

Figure 6: AI techniques in web
service composition system

Process algebra


The process algebra
describes the interactions
between the sub processes
and the order of
execution of these sub
processes


Equivalence notion


Preorder notion


Compatibility (preorder
notion)


Replaceability

(preorder
and equivalence notion )


S0

S1

a2

S2

a1

a2

a3

a3

S4

S4

S2

13

Figure 7 : replacing web service to overcome
failure participating web service

Temporal logic



Safety; The
system is a safe system if and only if all paths in the
system satisfy G(¬ unsafe
) )


Liveness
; The
liveness

is defined as the keeping of desirable property
to be
happened. GF(desirable
formula).
)


Fairness (
fair scheduling of the execution of processes
)


ufair

= GF
ѱ



Sfair

= GF
ѱ



GF
φ


Wfair

= FG
ѱ



GF
φ




14

Temporal logic

Work flow using
WBPEL

FSP

TEMPORAL
LOGIC MODEL
CHECKING

Satisfy

Not Satisfy

Desired proprieties

Non Desired proprieties

15

Figure 8: temporal logic model checking to verify
web service composition system

Conclusion


Dynamic
Vs

Static


-

implementation


-

performance and response time


-

reliability


-

adaptation to changes


-

verification and validation


The key point that we stress in this new classes is the formal
translation from the
standard speci

cation
languages to the
dedicated languages
of the existing model checkers, which makes
use of model checking


16

References

17


Figure 1 :
Papazoglou
, M.
Web Services: Principles and Technology

Prentice Hall,
2007
.


Figure 2:
Papazoglou
, M.
Web Services: Principles and Technology

Prentice Hall,
2007


Figure 3
:http
://
en.wikipedia.org/wiki/
Web_service


Figure
5: http
://www.softwareagility.gr/index.php?q=node/22





Thanks ………………

18