Specifying Workflow using COOPN

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Specifying Workflow using CO-OPN

• Ang Chen
• SMV group
• 11 Mars, 2005

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Plan

• Workflow patterns
• CO-OPN workflow building blocks
• Perspectives, patterns
• Abstract Data Type
• Reusability
• Verification, soundness
• Code generation and simulation
• Conclusion

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Workflow patterns

• Van Der Aalst
• 20 patterns, control-flow oriented
• Perspectives
• Control flow of cases (instances)
• Data data and information processing
• Operation interactions with human and external
  systems
• Resources

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Elements of Workflow

• Elements
• Activities
• Cases instances
• Actors (roles) human, machine
• Data, information
• Resources
• Processes
• How to define, deploy and execute processes?

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Our approach modeling workflow using algebraic
Petri net

• Specify pre- and post- conditions
• Represent activities by means of classes
• Using building blocks to model control-flows
• By connecting activities and building blocks, we
  define and construct workflows.
• Advantages reconfigurable, flexible, reusable.

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CO-OPN building blocks for workflow
Workflow CO-OPN Cases ADT Data ADT Activity Clas
s Process Context Operation Method Event Methods
/gate
Activity
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CO-OPN building blocks for workflow cont.
Top-down direction Data, operation and event
flow Left-right direction control-flow
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CO-OPN building blocks for workflow cont.
Example AND join
Hierarchies
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Perspectives

• We classify three stereotypes of methods and
  gates in our building blocks instance flow,
  action/event flow and data flow
• Methods are input flows, gates are output flows
• Instance flows are always fireable. Action/event
  flows and data flows are not, they may
  synchronize with each other.
• We predefine an ADT Case to represent instance
• Naturally we obtain three perspectives
• Control-flow flow of instance
• Data ADTs
• Operational methods and gates represent input
  and output actions/events

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Example

• Travel reservation
• Votation

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Algebraic Abstract Data Type
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Supported Workflow Patterns

• AND, OR Join/Split, choice, merge
• Multi-choice, synchronizing merge
• Multi-merge, discriminator, arbitrary cycles,
  implicit termination
• Multi-instance support

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Reusability

• Modularity
• Activity reusability
• Black box coordinal composition, the context
• White box class inheritance
• Patterns building block
• We define the process by creating a context
• Process reusability
• A process can be a component of another process
  composition of context
• Substitutability depend on criteria

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Verification

• Behaviors are defined by axioms
• Possible to prove properties using formal
  techniques

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Code generation and simulation

• Generate workflow controller
• Prototype interpretable
• Simulation in CoopnBuilder

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Conclusion

• CO-OPN provide a powerful way to represent
  business activities and processes
• Declarative activity definition using pre- and
  post- conditions
• Three perspectives are modeled contol-flow, data
  and operational
• ADT is an indispensable element