Folie 1

14.01.20086th Expert Meeting

Structure

Orchestration & Choreography

WSDL

Hands-on WSDL

Compensation and Exception

Hands-on Compensation and Exception

People links

Conclusion


Orchestration & Choreography

Choreography Orchestration

BPDM supports two fundamental views on processes, which complements each others

Orchestration & Choreography – WSDL – Exception – Compensation – People Links


Orchestration

is a short runner:

the processes are in one organization (= a unit with an established process flow)

central control

is one sequence finish in a part of a second



Choreography

is a long runner

describe the interactions between two or more organizations

no central control

helps to keep the enterprise loosely coupled and agile



An easy mental link …

there’s someone — the conductor — who tells everybody in the orchestra what to do and makes sure they all play in sync.

every dancer follows a pre-defined plan — everyone is independently of the others.

Choreography:

Orchestration:



WSDLWSDL

WSDL



WSDL is platform- and language-independent anddescribes four critical pieces of data: Interface information describing all publicly available

functions Data type information for all message requests and

message responses Binding information about the transport protocol to be

used Address information for locating the specified service

WSDL



Services are defined using six major elements:

<types>: What data types will be transmitted?

<message>: What messages will be transmitted?

<portType>: What operations (functions) will be supported?

<binding>: How will the messages be transmitted on the wire? What SOAP- specific details are there?

<service>: Where is the service located?

<port>: What address is specified for a binding?

WSDL



Client Server

Client Server

Client Server

Client Server

One-way

Request-Response

Solicit-Response

Notification

<input>

<input><output>

<output><input>

<output>

WSDL – portTypeWSDL – portType

Message exchange patterns:

WSDL



Messages

Types

PortTypes Operations

Bindings Operations

Services Ports

include

refer toabstract

definitions

concretedefinitions

modifiy

Elements of WSDL:

WSDL



SOA Exception Management

SOA Exception Management challengesSOA Exception Management challenges

There is a need for an exception management solution when we move from a component oriented world to a service oriented world.

Exception Management domain broadly covers exception logging exception notification and exception handling



SOA Fault handling and compensation

At some stage in a business process an issue may arise. some process is not completing due to an internal error business condition has not been met business process indicates that a failure scenario has been reached

But the BPEL process may have already invoked several other Web services

Fault handling and compensationFault handling and compensation



Compensation is the process of undoing successful work. Defines how a system is to attempt to recover itself when parts (or all) of a

BPEL process fails.




An approach for maintaining consistency over multiple systems.

Process

<scope> A

<catch> A<compensate scope=„A“>

<scope> B

<scope> C

<compensation handler> B<compensate scope=„C“>

<compensation handler> CAtkivität COMP-C.1

Aktivität A.1 ERROR




Problem: a business process may book a flight and a hotel.

If the flight reservation is successful, but the hotel reservation is not, the flight must be cancelled to restore the original state.

Compensation is user-defined and depends on the concrete problem at hand

Solution: the compensation handler could contact the airline Web service

again and cancel the flight or inform the person if another flight date would also be possible




Compensation handler contains arbitrary activities

for a scope which undoes the regular work of the scope

Compensate activity performed in the event that

not all corresponding updates of different systems succeed

<scope> <compensationHandler> <invokeoperation="CancelFlight"

... </invoke> </compensationHandler> <invoke

operation=“Confirm"...

</invoke>... <compensate scope=“BookCar" />

</scope>




Conclusion Compensation leads to looser coupling (concept of reducing the

dependencies between systems) of systems Could require more effort to implement BPEL has direct support for compensation

Since all services should be reusable, compensation is also important if no compensation is needed for the original project




Human TasksHuman Tasks

The actual Business Process Execution Language - BPEL 2.0 - has no standard for human tasks.

Of course all BPLE vendors integrate human tasks, but they all do it slightly different.

In 2005 SAP and IBM proposed “BPEL4People“, an optional extension to BPEL 2.0 which standardized human tasks in BPEL processes and published a white paper on that subject.

SOA – Human Tasks




BPEL4PeopleBPEL4People

Source: “ WS-BPEL Extension for People – BPEL4People“ by IBM and SAP

SOA – Human Tasks


People linksPeople links There are only a few business processes without human

interaction. With the existing tools it is possible to create a association

between the task and the person or group of persons who (can) execute the task.


but this can not be translated into BPEL.

SAP and IBM create in their white paper something called „people link“:„People links are used to represent the different groups of people who participate in the execution of a process. The

group of people associated with a generic human role is determined by a people link“.

SOA – Human Tasks


RésuméRésumé In 2007 – shortly before BPLE 2.0 was announced – the

white paper of BPEL4People was rejected.

Maybe standardizing the portType and basic features of the task management service would be a more practical approach than BPEL4People

Bruce Silver


SOA – Human Tasks


Importing BPEL from a BPA-Tool in a BPM-Platform

is leading to problemsOrchestration, choreography servers, implementation of WSDL and human interaction

to complicated for the operating department IT-department is overwhelmed Expert knowledge is necessary Danger of a bottleneck

our opinion: would be better to separate the cooperatemodeling into an extra tool

Conclusion


Thank you for your attention!Thank you for your attention!

Presentation:

Katja Borschert

Katharina Faustmann

Matthias Gerl

Matthias Multerer

Michael Preu

Florian Priller

Manuela Weiß

In the background:

Armin Eigenstetter

Renate Schambeck

Martin Schober

Sandra Stein

Tanja Stork

Thuy-Van Truong

Folie 1

Documents

Transcript of Folie 1