Bernard Szlachta at 16:18, 13 March 2013

2013-03-13T16:18:48Z

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{{Cat|SOA|60}}
{{Cat|BPM}}
{{Soa Links}}

*In SOA, services are typically parts of one or more distributed business processes
*Main motivations for services come from business processes.

==BPM vs BPM==
*'''Business process management''' usually refers to a technology-enabled means for companies to gain visibility and control over long-lived, multistep processes that span a wide range of systems and people in one or more organizations.
*'''Business process modeling''' is a set of practices or tasks that companies can perform to visually depict or describe all the aspects of a business process, including its flow, control and decision points, triggers and conditions for activity execution, the context in which an activity runs, and associated resources.

==BPM vs Workflow==
*A business process describes '''what''' has to be done (including input and output). It might include manual activities and might use any kinds of resources.
*A workflow describes '''how''' a certain result can be reached. It looks further into the details of all the steps or activities.

==Discovering BPM services==
*'''Top-down''' approach, you decompose a problem, system, or process into smaller chunks until you reach the level of (basic) services.
*'''Bottom-up''' approach, you build business processes by composing services into more general chunks.
*Agile, middle-ground

==Business Process Modeling==
A model is in fact just a representation of the process that allows companies to document, simulate, share, implement, evaluate, and continually improve their operations.

==Using Business Process Modeling Tools==
*Intalio
*ProcessMaker
*Oracle BPA
*ActiveBPM
*Tibco
*jBPM

[[File:Soa-bpm-modeling.jpg|850px]]

==BPEL==
*BPEL is an XML language for describing business flows and sequences,which in themselves are services
*Usually generated from a tool (and BPMN)

[[File:Soa-bpel.png]]

<invoke partnerLink="ncname" portType="qname" operation="ncname"
inputVariable="ncname"? outputVariable="ncname"?
standard-attributes>
standard-elements
...
<catch faultName="qname" faultVariable="ncname"?>*
activity
</catch>
<catchAll>?
activity
</catchAll>
...
</invoke>

'''BPEL Example'''

<?xml version="1.0"?>
<process name="changeAddress" ...>
<variables>
<variable messageType="..." name="...">
</variables>
<flow>
<receive .../> <!– for this request (operation and input) -->
<invoke .../> <!– call other service -->
<assign .../> <!– map data -->
<reply .../> <!– return data -->
</flow>
</process>

'''BPEL in Practise'''
*To compose and/or orchestrate services, you need services
*BPEL can be considered a business process assembler
*BPEL has error-handling support
*Data mappings

==Orchestration==
[[File:Soa-orchestration.png]]
*There is one central controller that coordinates all the activities of the process.
*You can apply the composite pattern, which means that the whole composition itself can be used as a service
*Orchestra and the conductor

==Choreography==
[[File:Soa-choreography.png|200px]]
*Each party is responsible for one or more steps.
*Nobody controls the process as a whole, and it might even be the case that nobody knows about or understands the process as a whole.
*Roundabout

==Orchestration vs Choreography==
*Orchestration depend on the “conductor”, hence it might not scale so well
*Centralization in orchestration creates order and control
*Choreography comes naturally and scale well, but there is no single entity responsible for the whole process
*Choreography depends highly on two things: collaboration and the specification of some general rules so that the collaboration doesn’t lead to chaos.

==Question==
*What does the BPM stand for?
*What are the trades-offs in case of top-down and bottom-up approach
*What is the BPEL?
*How does the BPMN and BPEL relates?

Business Process Management (BPM) - Revision history

Bernard Szlachta at 16:18, 13 March 2013