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Workflow Management Systems: Functions, architecture, and products.

Wil van der Aalst

Eindhoven University of TechnologyFaculty of Technology ManagementDepartment of Information and TechnologyP.O. Box 513 5600 MB EindhovenThe Netherlandsw.m.p.v.d.aalst@tm.tue.nl

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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.).

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Basic idea

• Separation of control and execution.

workflowmanagement

system

application

control (process logistics)

execution(task oriented)

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WfMC Reference model

Process Definition Tools

Administration & Monitoring

Tools

Interface 1

Interface 4Interface 5

Workflow Enactment Service

Workflow API and Interchange formats

Other WorkflowEnactment Service(s)

WorkflowClient

Applications

Interface 3Interface 2

WorkflowEngine(s)

WorkflowEngine(s)

InvokedApplications

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Data inside a WFS

procesdefinition

tool

resourceclassification

tool

analysis

tool

procesdefinitions

resourceclassifications

analysisdata

workflow

engine(s)

registration

generator

operationalcontroldata

historicaldata

internaldata

Logisticalcontroldata

otherworkflowsystems

customizedin-basket

standardin-basket

automaticalapplications

interactiveapplications

applicationdata

operational

tool

triggers

control

tool/report

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Interfaces

ProcessDefinition Tools

Administration& Monitoring

Tools

Interface 1

Interface 4Interface 5 Workflow Enactment Service Other WorkflowEnactment Service(s)

WorkflowClient

Applications

Interface 3Interface 2

WorkflowEngine(s)

WorkflowEngine(s)

InvokedApplications

Published in Handbook

Demo’s

Weak!

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Potential problem

workflowmanagement

system

application

In-basket application

server

client

database

Interface 3

workflowengine

DBMS

in-basket(worklist)

applications

server client

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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)

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Users of a WFS

workflowmanagement

systeem

administrator

process analist

workflowdesigner

end-user

manager

applicationdesigner/

programmer

databasedesigner/

programmer

applications

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Examples of systems

• COSA (demo)

• Staffware

• FLOWer

• …

Commercial Workflow Systems

1980 1985 1990 1995 2000

Exotica I - III

FlowMark MQSeries Workflow

jFlow

Staffware

Pavone

Onestone Domino Workflow

BEA PI

CARNOT

ViewStar

Digital Proc.Flo. AltaVista Proc.Flow

ActionWorkflow

SNI WorkParty

AdminFlow ChangengineWorkManager

OpenPM FlowJ et

Verve Versata

Action Coordinator

ActionWorks MetroDaVinci

FileNet WorkFlo Visual WorkFlo

FileNet Ensemble

Panagon WorkFlo

Xerox InConcert TIB/InConcert

Plexus FloWare BancTec FloWare

NCR ProcessIT

Netscape PM

MS2 Accelerate

Teamware Flow

Fujitsu iFlow

Beyond BeyondMail

DST AWD

IABG ProMInanD

DEC LinkWorks

COSA BaaN Ley COSA

Fujitsu Regatta

Pegasus

LEU

Banyan BeyondMail

Olivetti X_Workflow

Oracle WorkflowDigital Objectflow

ImagePlus FMS/FAF

VisualInfo

DST AWD

Continuum

Recognition Int.

WANGSIGMAEastman

WANG WorkfloweiStream

Lucent Mosaix

BlueCrossBlueShield

J CALS

iPlanet

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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.

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WfMC reference model

Process Definition Tools

Administration & Monitoring

Tools

Interface 1

Interface 4Interface 5

Workflow Enactment Service

Workflow API and Interchange formats

Other WorkflowEnactment Service(s)

WorkflowClient

Applications

Interface 3Interface 2

WorkflowEngine(s)

WorkflowEngine(s)

InvokedApplications

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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

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Staffware: The designer’s view

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Building blocks

start stop

step (i.e., task)

event step

automatic step

wait (i.e., AND-join)

condition (i.e., XOR-split)

complex router (OR-join/AND-split)

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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.

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Advanced semantics

time-out construct

withdraw construct

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Defining the process Double Check (DC)

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Adding a step

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Defining a step

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Defining a step (2)

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Defining forms and case variables

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Building a sequence

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Another step definition

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Another form definition

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Adding a set in parallel

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Another step definition

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Synchronizing two flows

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Another step definition

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Defining conditions

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The alternative route

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Another step definition

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Managing users/groups

Monitoring and managing

processes and cases

Staffware: The manager/administrator’s view

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Managing users

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Managing groups

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Making backups

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Managing Staffware tables

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Managing processes and cases

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Monitoring individual cases

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Managing Staffware lists

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Managing nodes

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Releasing changes

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The end-user’s view

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Selecting and executing the first step

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Executing one of the two parallel steps

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Executing the other one

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Executing the final step

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Audit trail

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Analysis of Staffware processes

6 runs (8 sequences) are possible!

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Example audit trails

Both OK One not OK

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Example audit trails (2)

Both not OK (seq) Both not OK (par)

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Analysis using Woflan

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Improved process

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Possible scenario’s

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Analysis using Woflan

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Exercises Staffware

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Translate to notation of book/course

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Translate to notation of book/course

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Model in Staffware

register c2 start search c 3 communicate

end

contact_ cust

c 5

c 6

c 7

book

insurance1?

insurance2?

c 9

c 10

c4

c 8

insurance1

insurance2

c 11

c 12

AND_ split AND_join c 13 send_documents c 14

cancel

start_ trip

c15

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Model in Staffware

start register

send_bill

receive_payment

archive

ship_goodscheck_availability

replenish

update

reminder

end

c1

c2

c3

c4

c5

c6

c7

c8

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Model in Staffware

start register

send_bill

receive_payment

archive

ship_goodscheck_availability

replenish

update

reminder

end

c1

c2

c3

c4

c5

c6

c7

c8

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Some more examples ...

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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)

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explicitlystructured

implicitlystructured

ad-hocstructured

unstructured

data-driven process-driven

ad-hoc workflow

groupware

productionworkflow

case handling

Oracle BPEL (Oracle)

Staffware (TIBCO)

COSA (COSA GmbH)

FLOWer (Pallas Athena)

SAP Business Workflow/Webflow

(SAP AG)

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COSA (COSA GmbH)

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COSA: Control flow perspective

• Based on Petri nets

• Lots of functionality

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COSA: Resource perspective

• One of the most powerful tools on the market.

• Multiple dimensions and rules.

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Oracle BPEL (Oracle)

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Oracle: Control flow perspective

• Based on BPEL

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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)

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ConstructsPrimitive 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.

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Oracle: Resource perspective

• Not part of BPEL (cf. BPEL4people).• Oracle specific task implementations.• Close to programming.

See Pattern-based Evaluation of Oracle-BPEL (v.10.1.2), N.A. Mulyar, 2005.

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SAP Business Workflow/Webflow (SAP AG)

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SAP: Control flow perspective

• Two views: native view and EPC view.

• Block structured.

e.g. sequence:

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Routing elements

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parallel routing

three types of choices

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join can hove a condition and/or lower bound

two types of loops

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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

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Logging in SAP Workflow

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FLOWer (Pallas Athena)

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FLOWer: Control flow perspective

• Block structured (similar to BPEL) but with excellent support for multiple instances.

• Can be generated from Protos.

• Case handling principle.

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

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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.

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Forms

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