Modern business process automation: YAWL and its support environment

Modern Business Process Automation

Arthur H. M. ter Hofstede • Wil M. P. van der Aalst

Michael Adams • Nick Russell

Editors

Modern

Business Process

Automation

YAWL and its Support Environment

123

Editors

Arthur H. M. ter Hofstede

Queensland University of

Technology

School of Information Systems

Fac. Information Technology

GPO Box 2434, level 5,

126 Margaret Street,

Brisbane QLD 4001

Australia

[email protected]

Wil M. P. van der Aalst

Eindhoven University of

Technology

Dept. Mathematics &

Computer Science

Den Dolech 2

5600 MB Eindhoven

Netherlands

[email protected]

Michael Adams

Queensland University of

Technology

School of Information Systems

Fac. Information Technology

GPO Box 2434, level 5,

126 Margaret Street,

Brisbane QLD 4001

Australia

[email protected]

Nick Russell

Eindhoven University of

Technology

Fac. Technology Management

Den Dolech 2

5600 MB Eindhoven

Netherlands

[email protected]

ISBN 978-3-642-03120-5 e-ISBN 978-3-642-03121-2

DOI 10.1007/978-3-642-03121-2

Springer Heidelberg Dordrecht London New York

Library of Congress Control Number: 2009931714

ACM Computing Classification (1998): J.1, H.4

c Springer-Verlag Berlin Heidelberg 2010

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Preface

The field of Business Process Management (BPM) is marred by a seemingly end￾less sequence of (proposed) industry standards. Contrary to other fields (e.g., civil

or electronic engineering), these standards are not the result of a widely supported

consolidation of well-understood and well-established concepts and practices. In the

BPM domain, it is frequently the case that BPM vendors opportunistically become

involved in the creation of proposed standards to exert or maintain their influence

and interests in the field. Despite the initial fervor associated with such standardiza￾tion activities, it is no less frequent that vendors either choose to drop their support

for standards that they earlier championed on an opportunistic basis or elect only to

partially support them in their commercial offerings.

Moreover, the results of the standardization processes themselves are a concern.

BPM standards tend to deal with complex concepts, yet they are never properly

defined and all-too-often not informed by established research. The result is a

plethora of languages and tools, with no consensus on concepts and their implemen￾tation. They also fail to provide clear direction in the way in which BPM standards

should evolve.

One can also observe a dichotomy between the “business” side of BPM and its

“technical” side. While it is clear that the application of BPM will fail if not placed

in a proper business context, it is equally clear that its application will go nowhere

if it remains merely a motivational exercise with schemas of business processes

hanging on the wall gathering dust.

An important observation that can be made about the state-of-the-art in BPM

relates to tool support. Tool support has evolved considerably in the past decade,

both in terms of the breadth of functionality that is provided and in terms of the

range and capabilities of the vendors who are involved. However, because of the

lack of effective standardization and direction in the field, BPM technology is not

widely used. Commercial BPM tools are rarely used in small and medium-sized

enterprises because of their prohibitive total cost of ownership. Acquisition costs

tend to be high, and ongoing operational support and maintenance commitments

can be even higher. One factor in this is that the closed nature of these products

means that their customization to specific client requirements may be difficult or

even impossible to achieve, and only the biggest users may be able to influence

their future feature set. Another issue is the scarcity of knowledge about individual

v

vi Preface

BPM offerings and the fact that product knowledge does not generalize. This means

that it remains difficult for end users to really leverage the capabilities of their BPM

investment.

So where does this leave those interested in the field of BPM? First, it is unwise

to become too aligned with or invest too heavily in particular standards, tools, or

technologies. These all come and go. It is imperative that the conceptual, formal,

and technological foundations of BPM are thoroughly understood. Only this way

can one survive the onslaught of “the latest and greatest” in BPM and not have the

wool pulled over one’s eyes by vendors, training organizations, and other interested

parties. Second, it is important to not only develop an understanding of the business

context of BPM and its main drivers but also of the fundamentals of business pro￾cess automation. To automate processes, it is vital to have a correct understanding of

the operation of the business processes. This can be obtained by process mining and

advanced simulation techniques. Measurable benefits can be realized by business

process automation if the right set of patterns is supported. Finally, the (increased)

uptake of Linux and other open-source products in the past decade has provided real

momentum for the open-source movement. This has also influenced the BPM land￾scape, and where once there was no alternative to commercial, closed-source, and

expensive solutions, such alternatives have now become viable in many instances.

The markedly lower acquisition costs and the ability to modify the software to suit

one’s own needs cannot be ignored as factors in software selection processes and

make the use of BPM technology an attractive proposition for a much wider range

of potential users, including those in small and medium-sized enterprises for whom

it was previously cost-prohibitive.

The book in front of you is the culmination of more than ten years of research

and development conducted at universities in different parts of the world. It aims

to provide the reader with a deep insight into fundamental concepts and tech￾niques that are core to understanding BPM and its application. The focus is not

on business/motivational aspects, though these aspects are not ignored.

The book is primarily intended as a textbook for undergraduate and postgrad￾uate students in the field of workflow, or BPM more broadly. However, it is also

eminently suitable as a reference for BPM researchers and professionals as it cov￾ers a wide range of BPM-related topics in a highly accessible yet thorough way.

Exercises to deepen the reader’s knowledge are provided throughout and the chap￾ter notes at the end of many chapters provide the reader with references to further

work in the area. The book uses YAWL (Yet Another Workflow Language), a powerful

language based on the well-known workflow patterns, and its open-source support

environment, to explain advanced concepts and their realization.

This book is an edited work and would not have been possible without the con￾tributions of a wide range of experts in the field. They take the reader through

the fundamentals of business process modeling and automation, various aspects of

flexibility, a number of current industry standards, and advanced topics such as inte￾gration, verification, mining, and configuration. In addition, implementation aspects

relevant to modern BPM environments are addressed in depth and applications of

BPM in the domains of health and screen business are discussed.

Preface vii

We feel privileged to have worked with many enthusiastic, committed, and

knowledgeable people over the years. In addition to the authors of the various chap￾ters in this book, we wish to thank the following people for their contributions

to the YAWL initiative: Lindsay Bradford, Carmen Bratosin, Ross Brown, Francesco

Cardi, Evan Chen, David Edmond, Tore Fjellheim, Matt Flaherty, Mike

Fowler, Andrew Hastie, Saphira Heijens, Sean Kneipp, Jan-Christian Kuhr,

Giancarlo La Medica, Massimiliano de Leoni, Alfredo Nantes, Ignatius Ong, Helen

Paik, Jessica Prestedge, Guy Redding, Dan Simkins, Alex Streit, David Truffet,

S´ebastien Vicente, and Kenneth Wang.

We also gratefully acknowledge support from the Australian Research Coun￾cil, the ARC Centre of Excellence for Creative Industries and Innovation, and the

Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO).

We sincerely hope that this book provides a valuable resource to the reader in the

years to come.

Brisbane, Australia Arthur ter Hofstede

Eindhoven, the Netherlands Wil van der Aalst

Brisbane, Australia Michael Adams

Eindhoven, the Netherlands Nick Russell

Contents

Part I Introduction

1 Introduction ................................................................... 3

Wil van der Aalst, Michael Adams, Arthur ter Hofstede, and

Nick Russell

1.1 Overview .............................................................. 3

1.2 On the Role of Models in BPM ...................................... 5

1.3 BPM Standard Approaches........................................... 7

1.4 The Workflow Patterns Initiative ..................................... 8

1.5 Petri Nets and Workflow Nets ........................................ 10

1.6 The Emergence of YAWL ............................................ 10

1.7 A Brief Overview of YAWL.......................................... 11

1.8 Positioning of YAWL ................................................. 14

1.9 Overview of the Book ................................................ 16

Part II Concepts

2 The Language: Rationale and Fundamentals ............................. 23

Nick Russell and Arthur ter Hofstede

2.1 Introduction ........................................................... 23

2.2 Workflow Patterns .................................................... 25

2.3 Formal Foundation .................................................... 50

2.4 Control-flow ........................................................... 57

2.5 Data .................................................................... 64

2.6 Resources.............................................................. 71

2.7 Syntax ................................................................. 87

2.8 Working Example ..................................................... 92

2.9 Conclusion ............................................................ 97

3 Advanced Synchronization ..................................................103

Moe Wynn, Wil van der Aalst, and Arthur ter Hofstede

3.1 Introduction ...........................................................103

3.2 The OR-Join Semantics...............................................104

ix

x Contents

3.3 Motivation .............................................................108

3.4 Operationalizing the OR-Join ........................................112

3.5 Conclusion ............................................................116

Part III Flexibility and Change

4 Dynamic Workflow ...........................................................123

Michael Adams

4.1 Introduction ...........................................................123

4.2 YAWL and Dynamic Workflow ......................................124

4.3 Worklets: Theoretical Basis ..........................................125

4.4 Conceptualization of Worklets .......................................128

4.5 Context, Rules, and Worklet Selection...............................129

4.6 The Selection Process.................................................134

4.7 Service Interface ......................................................136

4.8 Secondary Data Sources ..............................................139

4.9 Conclusion ............................................................140

5 Exception Handling ..........................................................147

Michael Adams and Nick Russell

5.1 Overview ..............................................................147

5.2 A General Framework for Exception Handling .....................148

5.3 YAWLeX: A Graphical Exception Handling Language ............154

5.4 Exception Handling in YAWL .......................................158

5.5 Epilogue ...............................................................170

6 Declarative Workflow ........................................................175

Maja Pesic, Helen Schonenberg, and Wil van der Aalst

6.1 Introduction ...........................................................175

6.2 Constraint-based Workflow Specification ...........................179

6.3 Enactment of Constraint Model Instances ...........................190

6.4 Dynamic Instance Change ............................................194

6.5 Conclusions ...........................................................196

Part IV The Core System

7 The Architecture ..............................................................205

Michael Adams, Marlon Dumas, and Marcello La Rosa

7.1 Architectural and Implementation Considerations ..................205

7.2 A Three-Tier View of the YAWL System............................206

7.3 YAWL Services and Interfaces .......................................209

7.4 Summary ..............................................................218

Contents xi

8 The Design Environment ....................................................221

Stephan Clemens, Marcello La Rosa, and Arthur ter Hofstede

8.1 Introduction ...........................................................221

8.2 Setting up the Process Control Logic ................................222

8.3 Defining Data Aspects ................................................227

8.4 Assigning Human Resources to the Process .........................231

8.5 Error Reporting .......................................................234

8.6 Specification File .....................................................236

8.7 Summary ..............................................................238

9 The Runtime Environment ..................................................241

Michael Adams

9.1 Introduction ...........................................................241

9.2 Basic Operations ......................................................241

9.3 Internal Architecture ..................................................243

9.4 The Life-Cycle of a Case .............................................246

9.5 The Life-Cycle of a Work item .......................................249

9.6 Persistence.............................................................252

9.7 Logging................................................................254

9.8 Summary ..............................................................257

Part V Services

10 The Resource Service.........................................................261

Michael Adams

10.1 Introduction ...........................................................261

10.2 Functional Overview..................................................261

10.3 Organizational Model.................................................265

10.4 Architecture ...........................................................269

10.5 Initial Distribution ....................................................278

10.6 Privileges ..............................................................281

10.7 The Worklist ..........................................................284

10.8 Conclusion ............................................................288

11 The Worklet Service ..........................................................291

Michael Adams

11.1 Introduction ...........................................................291

11.2 Service Overview .....................................................291

11.3 Service Oriented Architecture ........................................293

11.4 Worklet Service Architecture.........................................295

11.5 Service Installation and Configuration ...............................298

11.6 Worklet Process Definition ...........................................301

11.7 Exlet Process Definition ..............................................306

11.8 Ripple-Down Rule Sets ...............................................312

11.9 Extending the Available Conditionals ...............................314

11.10 The Rules Editor ......................................................315

xii Contents

12 The Declare Service ..........................................................327

Maja Pesic, Helen Schonenberg, and Wil van der Aalst

12.1 Introduction ...........................................................327

12.2 Service Architecture ..................................................328

12.3 Constraint Templates .................................................330

12.4 Constraint Workflow Models .........................................330

12.5 Verification of Constraint Models ....................................333

12.6 Execution of Constraint Model Instances............................333

12.7 Optional Constraints ..................................................336

12.8 Dynamic Instance Change ............................................337

12.9 Decompositions of YAWL and Declarative Workflows .............339

12.10 Conclusions ...........................................................341

Part VI Positioning

13 The Business Process Modeling Notation ..................................347

Gero Decker, Remco Dijkman, Marlon Dumas,

and Luciano Garc´ıa-Ba˜nuelos

13.1 Introduction ...........................................................347

13.2 BPMN .................................................................348

13.3 Mapping BPMN to YAWL ...........................................355

13.4 Tool Support ..........................................................364

13.5 Summary ..............................................................365

14 EPCs ...........................................................................369

Jan Mendling

14.1 Introduction ...........................................................369

14.2 Event-Driven Process Chains.........................................370

14.3 Pattern Comparison of YAWL and EPCs ............................372

14.4 Mapping EPCs to YAWL .............................................373

14.5 Mapping YAWL to EPCs .............................................374

14.6 Transformation by Synthesis .........................................379

14.7 Conclusion ............................................................381

15 The Business Process Execution Language ................................385

Chun Ouyang, Marlon Dumas, and Petia Wohed

15.1 Introduction ...........................................................385

15.2 Overview of BPEL through the YAWL Prism.......................387

15.3 Workflow Patterns Support ...........................................394

15.4 Epilogue ...............................................................398

16 Open Source Workflow Systems ............................................401

Petia Wohed, Birger Andersson, and Paul Johannesson

16.1 Introduction ...........................................................401

16.2 OpenWFEru: Ruote ...................................................401

Contents xiii

16.3 jBPM ..................................................................411

16.4 Enhydra Shark ........................................................422

16.5 Epilogue ...............................................................431

Part VII Advanced Topics

17 Process Mining and Simulation .............................................437

Moe Wynn and Anne Rozinat and Wil van der Aalst and

Arthur ter Hofstede, and Colin Fidge

17.1 Introduction ...........................................................437

17.2 Payment Process ......................................................437

17.3 Process Mining and YAWL...........................................438

17.4 Process Simulation and YAWL.......................................443

17.5 Conclusion ............................................................454

18 Process Configuration ........................................................459

Florian Gottschalk and Marcello La Rosa

18.1 Introduction ...........................................................459

18.2 How Does Process Configuration Work? ............................460

18.3 Configuring YAWL Models ..........................................462

18.4 Steering Process Configuration Through Questionnaires ...........468

18.5 Applying Configuration Decisions to YAWL Models...............474

18.6 Tool Support ..........................................................480

18.7 Summary ..............................................................483

19 Process Integration ...........................................................489

Lachlan Aldred

19.1 Introduction ...........................................................489

19.2 Coupling Dimensions .................................................495

19.3 Batch Messaging ......................................................501

19.4 Seeking Feedback: Bidirectional Interactions .......................502

19.5 Composed Interactions ...............................................504

19.6 Event-based Process Patterns.........................................506

19.7 Transformations .......................................................507

19.8 Process Discovery.....................................................508

19.9 Conclusion ............................................................509

20 Verification ....................................................................513

Eric Verbeek and Moe Wynn

20.1 Introduction ...........................................................513

20.2 Preliminaries ..........................................................514

20.3 Soundness of YAWL Models .........................................517

20.4 Soundness-Preserving Reduction Rules .............................521

20.5 Structural Invariant Properties........................................533

xiv Contents

20.6 Tools ...................................................................534

20.7 Concluding Remarks..................................................536

Part VIII Case Studies

21 YAWL4Healthcare............................................................543

Ronny Mans and Wil van der Aalst and Nick Russell and

Arnold Moleman and Piet Bakker, and Monique Jaspers

21.1 Introduction ...........................................................543

21.2 Healthcare Processes..................................................545

21.3 Gynecological Oncology .............................................547

21.4 Realization ............................................................553

21.5 Conclusions ...........................................................561

22 YAWL4Film ...................................................................567

Chun Ouyang

22.1 Introduction ...........................................................567

22.2 Overview of Film Production Processes .............................568

22.3 YAWL4Film Design and Implementation ...........................570

22.4 YAWL4Film Deployment ............................................578

22.5 Pilot Applications: Rope Burn and Family Man .....................584

22.6 Epilogue ...............................................................585

Exercises .......................................................................585

Part IX Epilogue

23 Epilogue .......................................................................591

Wil van der Aalst, Michael Adams, Arthur ter Hofstede, and

Nick Russell

23.1 Overview ..............................................................591

23.2 Positioning of YAWL .................................................593

23.3 Analysis ...............................................................594

23.4 Next Steps .............................................................596

Part X Appendices

A The Order Fulfillment Process Model......................................599

Marcello La Rosa, Stephan Clemens, and Arthur ter Hofstede

A.1 Introduction ...........................................................599

A.2 Overall Process........................................................599

A.3 Ordering ...............................................................603

A.4 Carrier Appointment ..................................................604

A.5 Payment ...............................................................607

A.6 Freight in Transit......................................................608

A.7 Freight Delivered .....................................................609

Contents xv

A.8 Showcased YAWL features ...........................................610

A.9 Setup ...................................................................612

B Mathematical Notation.......................................................613

Nick Russell

C The Original Workflow Patterns............................................615

Nick Russell

References...........................................................................617

Index .................................................................................635

Cited Author Index ................................................................665

Acronyms ...........................................................................671

Useful Websites.....................................................................675

Contributors

W.M.P. (Wil) van der Aalst Eindhoven University of Technology, Eindhoven,

the Netherlands

M. (Michael) Adams Queensland University of Technology, Brisbane, Australia

L. (Lachlan) Aldred Queensland University of Technology, Brisbane, Australia

B. (Birger) Andersson Stockholm University and The Royal Institute of

Technology, Stockholm, Sweden

P.J.M. (Piet) Bakker Academic Medical Center, Amsterdam, the Netherlands

S. (Stephan) Clemens Queensland University of Technology, Brisbane, Australia

G. (Gero) Decker University of Potsdam, Berlin, Germany

R.M. (Remco) Dijkman Eindhoven University of Technology, Eindhoven,

the Netherlands

M. (Marlon) Dumas University of Tartu, Tartu, Estonia

C.J. (Colin) Fidge Queensland University of Technology, Brisbane, Australia

L. (Luciano) Garc´ıa-Banuelos ˜ Universidad Aut´onoma de Tlaxcala, Tlaxcala,

Mexico

F. (Florian) Gottschalk Eindhoven University of Technology, Eindhoven,

the Netherlands

A.H.M. (Arthur) ter Hofstede Queensland University of Technology, Brisbane,

Australia

M.W.M. (Monique) Jaspers University of Amsterdam, Amsterdam,

the Netherlands

P. (Paul) Johannesson Stockholm University and The Royal Institute of

Technology, Stockholm, Sweden

M. (Marcello) La Rosa Queensland University of Technology, Brisbane,

Australia

xvii