1 Workflow Management Systems : Functions, architecture, and products. Wil van der Aalst Eindhoven University of Technology Faculty of Technology Management Department of Information and Technology P.O. Box MB Eindhoven The Netherlands

2 Focus on "classical" workflow management systems, but... Four types of "workflow-like" systems: 1.Information systems with hard-coded workflows (process& organization specific). 2.Custom-made information systems with generic workflow support (organization specific). 3.Generic software with embedded workflow functionality (e.g., the workflow components of ERP, CRM, PDM, etc. systems). 4.Generic software focusing on workflow functionality (e.g., Staffware, MQSeries Workflow, FLOWer, COSA, Oracle BPEL, Filenet, etc.).

3 Basic idea Separation of control and execution. workflow management system application control (process logistics) execution (task oriented)

4 WfMC Reference model

5 Data inside a WFS

6 Interfaces Published in Handbook Demo’s Weak!

7 Potential problem workflow engine DBMS in-basket (worklist) applications serverclient

8 The ACID-properties, known from transaction processing, should hold. Atomicity (atomic, "everything or nothing", rollback if necessary) Consistency (a completed task results in a proper state of the system) Isolation (tasks do not affected each other, even if they are executed in parallel) Durability (the result of a completed task may not get lost; commit tasks)

9 Users of a WFS

10 Examples of systems COSA (demo) Staffware FLOWer …

11 Staffware Leading workflow management system (typically 25 percent of the global “pure” workflow market). Staffware PLC is headquartered in Maidenhead UK and has offices in 19 countries. Focus on performance and reliability rather than functionality (e.g., infinite scalability, fault tolerance, etc.) In the remainder, we present a small case study that is used to: –introduce the design tool and modeling language of Staffware, –show the management/administrator tools of Staffware, –demonstrate the end-user’s view of Staffware, and –show the need for analysis.

12 WfMC reference model

13 A small case study: Double Check (DC) Processing of insurance claims involving registration, two checks, and a payment of rejection Five tasks: –register (register insurance claim) –checkA (check insurance policy) –checkB (check damage reported) –pay (pay for the damage) –reject (inform customer about rejection) Registration is followed by two checks which can be handled in parallel. Each of the checks results in “OK” or “not OK”. If both are OK, pay otherwise reject. Three roles: register (for task register), checks (for both checks), and pay/reject (for final tasks). register checkA checkB pay reject

14 Staffware: The designer’s view

15 Building blocks startstop step (i.e., task) event step automatic step wait (i.e., AND-join) condition (i.e., XOR- split) complex router (OR-join/AND-split)

16

17 Basic semantics of a step OR-join AND-split Same for complex routers, conditions (input: OR, output: each branch is AND), other types of steps, etc.

18 Advanced semantics time-out construct withdraw construct

19 Defining the process Double Check (DC)

20 Adding a step

21 Defining a step

22 Defining a step (2)

23 Defining forms and case variables

24 Building a sequence

25 Another step definition

26 Another form definition

27 Adding a set in parallel

28 Another step definition

29 Synchronizing two flows

30 Another step definition

31 Defining conditions

32 The alternative route

33 Another step definition

34 Managing users/groups Monitoring and managing processes and cases Staffware: The manager/administrator’s view

35 Managing users

36 Managing groups

37 Making backups

38 Managing Staffware tables

39 Managing processes and cases

40 Monitoring individual cases

41 Managing Staffware lists

42 Managing nodes

43 Releasing changes

44 The end-user’s view

45 Selecting and executing the first step

46 Executing one of the two parallel steps

47 Executing the other one

48 Executing the final step

49 Audit trail

50 Analysis of Staffware processes 6 runs (8 sequences) are possible!

51 Example audit trails Both OK One not OK

52 Example audit trails (2) Both not OK (seq) Both not OK (par)

53 Analysis using Woflan

54 Improved process

55 Possible scenario’s

56 Analysis using Woflan

57 Exercises Staffware

58 Translate to notation of book/course

59 Translate to notation of book/course

60 Model in Staffware

61 Model in Staffware

62 Model in Staffware

63 Some more examples...

64 Four types of "workflow-like" systems: 1.Information systems with hard-coded workflows (process& organization specific). 2.Custom-made information systems with generic workflow support (organization specific). 3.Generic software with embedded workflow functionality (e.g., the workflow components of ERP, CRM, PDM, etc. systems). 4.Generic software focusing on workflow functionality Oracle BPEL (Oracle) Staffware (TIBCO) COSA (COSA GmbH) FLOWer (Pallas Athena) SAP Business Workflow/Webflow (SAP AG)

65 Oracle BPEL (Oracle) Staffware (TIBCO) COSA (COSA GmbH) FLOWer (Pallas Athena) SAP Business Workflow/Webflow (SAP AG)

66 COSA (COSA GmbH)

67 COSA: Control flow perspective Based on Petri nets Lots of functionality

68 COSA: Resource perspective One of the most powerful tools on the market. Multiple dimensions and rules.

69

70 Oracle BPEL (Oracle)

71 Oracle: Control flow perspective Based on BPEL

72 BPEL(4WS) – Business Process Execution Language for Web Services Compromise between IBM and Microsoft. Merges WSFL and XLANG. Two styles of working: graph based and structured. Expressive but complex language. Support by many vendors: IBM Websphere, Oracle BPEL, and at least 16 more products. In April 2003, BEA Systems, IBM, Microsoft, SAP AG and Siebel Systems submitted BPEL4WS 1.1 to OASIS. Version 2.0 will have subtle but significant differences. Two flavors: executable and abstract (non-executable)

73 Constructs Primitive activities invoke, invoking an operation on some web service; receive, waiting for a message from an external source; reply, replying to an external source; wait, waiting for some time; assign, copying data from one place to another; throw, indicating errors in the execution; terminate, terminating the entire service instance; and empty, doing nothing. Structured activities sequence, for defining an execution order; switch, for conditional routing; while, for looping; pick, for race conditions based on timing or external triggers; flow, for parallel routing; and scope, for grouping activities to be treated by the same fault-handler. Activities can be nested. Can be connect though links.

74 Oracle: Resource perspective Not part of BPEL (cf. BPEL4people). Oracle specific task implementations. Close to programming. See Pattern-based Evaluation of Oracle-BPEL (v ), N.A. Mulyar, 2005.

75 SAP Business Workflow/Webflow (SAP AG)

76 SAP: Control flow perspective Two views: native view and EPC view. Block structured. e.g. sequence:

77 Routing elements

78 parallel routing three types of choices

79 join can hove a condition and/or lower bound two types of loops

80 SAP: Resource perspective Organizational units have positions that may or may not be occupied. Positions may be associated to multiple jobs (kind of role). You can assign a task to –an organizational unit, if it is to apply to all subordinate positions –a job, if it is to apply to all positions described by the job –a position, if it is to apply to those persons (employees) or users who hold the position –a person (employee), if it is to apply to this person

81 Logging in SAP Workflow

82 FLOWer (Pallas Athena)

83 FLOWer: Control flow perspective Block structured (similar to BPEL) but with excellent support for multiple instances. Can be generated from Protos. Case handling principle.

84 Partly block structured: choices, loops, etc. require an additional level

85 FLOWer: Resource perspective Three roles for step in the process (execute, redo, skip). Hierarchies can be defined independent of process. Various was to view/distribute work.

86 Forms

87