A Rigorous Semantics for BPMN 2.0 Process Diagrams (eBook)

The authors are experienced industrial researchers in the field of computer science and software engineering, with experience in business process modelling and formal methods in particular. They have been working in a joint team from the Software Competence Center Hagenberg (SCCH) and the Institute for Application Oriented Knowledge Processing (FAW) of the Johannes Kepler University Linz (JKU), both in Austria.

Preface 6
Contents 8
1 Introduction 12
1.1 Motivation 13
1.2 Intended Readership and Relevance 18
1.3 Outline 19
2 State of the Art 20
2.1 An Overview of Business Process Modelling Techniques 20
2.2 Formal Representations of BPMN 22
2.3 Suitability of BPMN for Business Process Modelling 24
3 Modelling Semantics with Abstract State Machines 28
3.1 General Features of the ASM Method 29
3.2 The ASM Notation Used in This Book 33
3.2.1 Rules 33
3.2.2 Derived Functions 35
3.2.3 Local Constants and Variables and New DataElements 35
3.2.4 Assertions 36
3.2.5 Types of Functions and Universes 36
3.2.6 Signatures of Functions and Rules 37
3.2.7 Boolean Expressions 37
3.2.8 Set Expressions 38
3.2.9 Naming Conventions 38
4 A Rigorous Semantics for BPMN 2.0 Process Diagrams 40
4.1 Process Diagrams 41
4.2 Framework 44
4.2.1 Initialisation and Top-Level Process Management 44
4.2.2 Workflow Transition Interpreter 45
4.2.2.1 Token Concept 46
4.2.3 Flow Nodes 47
4.2.3.1 Node Transition 49
4.2.3.2 Instance Transition 51
4.2.3.3 Process vs. Activity 51
4.3 Control Flow 53
4.3.1 Producing Tokens 54
4.3.2 Consuming Tokens 54
4.4 Instantiation, Deletion, and Interruption 55
4.4.1 Creating Instances 55
4.4.2 Deleting Instances 56
4.4.3 Interrupting Activities 57
4.5 Activities 60
4.5.1 Send Tasks and Receive Tasks 62
4.5.2 Common Semantics of Activities 63
4.5.3 Tasks 67
4.5.4 Sub-processes 71
4.5.5 Event Sub-processes 74
4.5.6 Transaction Sub-processes 75
4.5.7 Ad Hoc Sub-processes 78
4.5.8 Compensation 80
4.5.8.1 Rules Concerning Compensation 81
4.5.8.2 Functions Concerning Compensation 82
4.5.9 Call Activities 82
4.5.10 Loop Activities 84
4.5.10.1 Standard Loop 88
4.5.10.2 Sequential Multi-instance Loop 90
4.5.10.3 Parallel Multi-instance Loop 92
4.6 Gateways 94
4.6.1 Parallel Gateways 97
4.6.2 Exclusive Gateways 99
4.6.3 Inclusive Gateways 101
4.6.4 Complex Gateways 107
4.6.5 Event-Based Gateways 113
4.7 Events 117
4.7.1 Event Transition 119
4.7.2 Catching Events 119
4.7.3 Start Events 124
4.7.4 Start Events of Top-Level Processes 126
4.7.5 Start Events of Embedded Sub-processes 133
4.7.6 Start Events of Event Sub-processes 134
4.7.7 Boundary Start Events 139
4.7.8 Intermediate Catching Events 142
4.7.9 Catching Link Events 145
4.7.10 Intermediate Boundary Events 147
4.7.11 Throwing Events 151
4.7.12 End Events 154
4.7.13 Intermediate Throwing Events 155
4.7.14 Throw a Compensation Event 156
4.7.14.1 Throw an Exception 158
4.8 Data 159
4.9 Miscellaneous 161
4.9.1 Scope 161
4.9.2 Message Flow 161
4.9.3 Swimlanes 162
4.9.4 Artefacts 163
4.9.5 Conversation 163
4.9.6 Correlation 163
4.9.7 Choreography 163
5 How the Semantic Model Can Be Used 164
5.1 Validation and Verification 165
5.2 Validation 166
5.3 Verification 169
6 A Discussion of BPMN 2.0 171
6.1 General Remarks on BPMN 172
6.2 Deviations Between Our Model and the BPMN 2.0 Standard 175
6.2.1 Conflicting Provisions in the Standard 175
6.2.2 Superfluous Elements 176
6.3 Suggestions for Further Improvements 177
6.3.1 Potential for Semantic Simplification 177
6.3.2 Process Instantiation by Mixed-Behaviour Elements 178
6.3.3 Other Mixed-Behaviour Elements and Further Possible Simplifications 181
6.3.4 Object-Oriented vs. Subject-Oriented Approaches 182
6.3.5 Modelling Issues Currently not Covered by BPMN 183
7 Towards a Workflow Engine by Stepwise Refinement 184
7.1 Workflow Interpreter (WI) 184
7.2 Context 186
7.2.1 Static Context 186
7.2.2 Root Context 187
7.2.3 Sub-context 187
7.3 Notifications 188
7.4 Implicit Notifications 190
7.5 Message and Signal Pool 191
7.6 Event Publication 192
7.7 Event Propagation 193
7.8 Deployment Manager and Deployments 194
7.8.1 Deployments 194
7.8.2 Deployment Manager 195
7.9 Instance Manager 196
7.10 Further Refinements 198
8 Discussion of the Proposed Specification and Outlook 199
8.1 Deontic BPMN 200
8.2 A Layered Approach for Actor Modelling 201
8.3 Integration of User Interaction Modelling 202
8.4 Towards an Enhanced Communication Concept 203
8.5 Integration of Data Modelling 204
8.6 Towards an eP2 Architecture 205
A The Signature of the Ground Model 206
A.1 Auxiliary Functions and Constructs Used 206
A.2 Basic Functions (Signature) 208
A.2.1 Primitive Types 208
A.2.2 Universes 209
A.2.2.1 Regarding Flow Nodes and Connecting Objects 210
A.2.2.2 Regarding Lifecycle States 211
A.2.2.3 Regarding Event Triggers 212
A.2.3 Static Functions 214
A.2.3.1 Regarding Processes 214
A.2.3.2 Regarding Flow Nodes 215
A.2.3.3 Regarding Event Definitions 219
A.2.3.4 Regarding Connecting Objects 219
A.2.3.5 Regarding Data 220
A.2.4 Shared Functions 220
A.2.5 Monitored Functions 221
A.2.6 Controlled Functions 222
A.2.6.1 Regarding Instances 222
A.2.6.2 Regarding Flow Nodes 223
A.2.6.3 Regarding Connecting Objects 223
A.2.6.4 Regarding Tokens 224
A.2.6.5 Regarding Event Triggers 224
B List of Acronyms 225
C BPMN Symbols 227
References 229
Index 238