业务过程自动化part2

Patterns

Definition of Pattern

Abstraction from concrete form which keeps recurring in specific, non-arbitrary contexts

Classes of control-flow patterns

Branching Patterns

capture branching scenarios in processes.

• parallel—— AND Split
• Multi-choice —— OR Split
• exclusive choice —— XOR Split
• deferred choice （to user and/or environment） —— XOR Split
• Thread Split —— thread of control is split into multiple concurrent threads in same branch

Synchronisation Patterns

describe synchronization scenarios arising in processes
wait!

AND-join variants

• Synchronisation
• Generalised AND-Join
• Structured partial join
• Blocking partial join
• Cancelling partial join

OR-join variants

• Structured synchronising merge
• Local synchronising merge
• General synchronising merge

XOR and thread join

• Simple merge
• Multi-merge
• Thread merge

Repetition Patterns

describe various ways in which repetition may be specified

• Structured loop
• Arbitrary cycles
• Recursion

Multiple Instance(MI) Patterns

delineate situations with multiple threads of execution in a workflow which relate to the same activity.

• MI without Synchronisation
• MI with a priori Design Time Knowledge
• MI with a priori Runtime Knowledge
• MI without a priori Runtime Knowledge
• Static Partial Join for MI
• Cancelling Partial Join for MI
• Dynamic Partial Join for MI

Concurrency Patterns

reflect situations where restrictions are imposed on the extent of concurrent control-flow in a process instance

• Sequence
• Interleaved routing
• Critical section
• Milestone

Trigger Patterns

catalogue the different triggering mechanisms appearing in a process context

• Transient trigger
• Persistent Trigger

Cancellation and Completion Patterns

categorise the various cancellation scenarios that may be relevant for a workflow specification

• Cancel task
• Cancel case
• Cancel region
• Cancel MI task
• Complete MI task

Termination Patterns

address the issue of when the execution of a workflow is considered to be finished

• Implicit termination
• Explicit termination

---

verification

soundness

• Option to complete
  Any executing instance of the YAWL net must eventually terminate.
• **Proper completion **
  At the moment of termination there must be precisely one token in the end condition and all other conditions are empty.
• **No dead tasks **
  Any task can be executed for some case.

Relaxed soundness

For every task, some proper completing case must exist

Weak soundness

Weak option to complete
——It is possible to complete a case.