10th 11th July 2003

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Smart OrganizationsWorkflow TechnologiesWeb
Services

• Gökçe Banu Laleci
• METU

HERMES IST-2000-26429
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What is Workflow Management?
HERMES IST-2000-26429
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Workflow

• Workflows are activities involving the
  coordinated execution of
• multiple tasks performed by different processing
  entities,
• mostly in distributed heterogeneous environments
• which are very common in enterprises of even
  moderate complexity

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Workflow

• A workflow system can be defined as a collection
  of processing steps (also termed as tasks or
  activities) organized to accomplish some business
  process
• A task may represent a manual operation by a
  human or a computerazible task to execute legacy
  applications, access databases, control
  instrumentation, sense events in the external
  world, or even affect physical changes

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Workflow

• In addition to the collection of tasks, a
  workflow defines the order of task invocation or
  condition(s) under which tasks must be invoked
  (i.e. control-flow) and data-flow between these
  tasks

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Workflow Process

• The automation of a business process, in whole or
  part, during which documents, information, or
  tasks are passed from one participant to another
  for acting, according to a set of procedural
  rules. WfMC
• Workflow is about defining and executing a series
  of tasks in the course of executing a business
  process. Concordium97
• Workflow is the process by which individual tasks
  come together to complete a transaction - a
  clearly defined business process - within an
  enterprise. ActionTech95

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The major components of a workflow system

• Process Definition Tools
• Workflow Enactment Service
• Administration and Monitoring tools
• Workflow Client Applications
• Invoked Applications

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A Workflow Reference Model
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The Workflow Enactment Software

• The workflow enactment software
• interprets the process description and
• controls the instantiation of processes and
• sequencing of activities,
• adding work items to the user work lists and
• invoking application tools as
• necessary.
• This is done through one or more co-operating
  workflow management engines, which manage(s) the
  execution of individual instances of the various
  processes.

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The Workflow Enactment Software

• The workflow enactment service maintains internal
  control data either centralised or distributed
  across a set of workflow engines
• workflow control data includes
• the internal state information associated with
  the various process and activity instances under
  execution
• checkpointing and recovery/restart information
  used by the workflow engines to co-ordinate and
  recover from failure conditions

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Workflow Engine

• A software service or "engine" that provides the
  run time execution environment for a workflow
  instance
• Typically such software provides facilities to
  handle
• interpretation of the process definition
• control of process instances - creation,
  activation, suspension, termination, etc
• navigation between process activities, which may
  involve sequential or parallel operations,
  deadline scheduling, interpretation of workflow
  relevant data, etc

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Workflow Engine

• sign-on and sign-off of specific participants
• identification of work items for user attention
  and an interface to support user interactions
• maintenance of workflow control data and workflow
  relevant data, passing workflow relevant data
  to/from applications or users
• an interface to invoke external applications and
  link any workflow relevant data
• supervisory actions for control, administration
  and audit purposes

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Workflow Engine

• A workflow engine can control the execution of a
  set of process, or sub-process, instances with a
  defined scope - determined by the range of object
  types, and their attributes, which it can
  interpret within the process definition(s)
• In an enactment service consisting of multiple
  workflow engines, there is a partitioning of
  process execution across the constituent engines

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Process Definition Tools

• A process definition tool should be able to
  express the data and control flow within a
  process as well as the activities and the roles
  involved
• The WfMC has identified a set of six primitives
  with which it is possible to describe flows and
  hence construct a workflow specification
• With these primitives it is possible to model any
  workflow that is likely to occur
• These primitives are AND-split, AND-join,
  OR-split, OR-join and repeatable task.

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Workflow Client Applications

• In the workflow model interaction occurs between
  the client application and the workflow engine
  through a well defined interface embracing the
  concept of a worklist - the queue of work items
  assigned to a particular user (or, possibly,
  group of common users) by the workflow engine
• At the simplest level the worklist is accessible
  to the workflow engine for the purposes of
  assigning work items and to the worklist handler
  for the purpose of retrieving work items for
  presentation to the user for processing

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Activity/Task/Step

• An activity is
• a collection of events,
• a set of logically related operations or
• a bounded computation
• that can be made to occur by a single logical
  actor (e.g., by a person with a given role) or a
  processing entity (information system, resource
  manager).
• Example review a damage claim assessment, fill
  out a complaint form, perform a database
  transaction

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Work Item

• A message that represents work to be performed.
• A work item is used to manipulate (e.g. relay,
  store, schedule) work for the purpose of doing it
  later or elsewhere. Example a fax asking about
  the damage claim assessment that should have been
  there 3 days ago.

Data Item
An object that represents information, which is
needed to perform some activity. Example a
photograph of the damage, taken on location.
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Worklist

• A list of work items retrieved from a workflow
  management system.
• A worklist is used by an actor as a to-do list.

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Invoked Applications

• A Workflow Management System should be able to
  invoke applications
• The invoked application may be local to the
  workflow engine, co-resident on the same platform
  or located on a separate, network accessible
  heterogeneous platform the process definition
  should contain sufficient application type and
  addressing information (specific to the needs of
  the workflow engine) to invoke the application

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Administrative and Monitoring Tools

• Within a workflow system there are a number of
  supervisory functions which are normally
  provided.
• These functions may enable supervisors
• to alter work allocation rules,
• to identify participants for specific
  organisational roles within a process,
• to track alerts for missed deadlines or other
  forms of event,
• to trace the history of a particular process
  instance,
• to enquire about work throughput or other
  statistics, etc.

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Workflow Management

• Workflow Management (WFM) is the automated
  coordination, control, and communication of work,
  both of people and computers, in the context of
  organizational processes, through the execution
  of software in a network of computers whose order
  of execution is controlled by a computerized
  representation of the business processes.
• Joosten

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Workflow Management System

• A system that defines, creates and manages the
  execution of workflows through the use of
  software, running on one or more workflow
  engines, which is able to interpret the process
  definition, interact with workflow participants
  and, where required, invoke the use of IT tools
  and applications. WfMC
• A set of tools providing support for process
  definition, workflow enactment, and
  administration and monitoring of workflow process.

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Workflow Management System

• A Workflow Management System (abbreviated WFMS)
  is a technological system in which workflow
  processes are defined, performed, managed, and
  monitored through the execution of software whose
  order of events is driven by a process
  definition.

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Who is WFMC?

• Non-profit organisation founded 1993
• Mission is to promote the use of workflow through
  establishment of standards for
• software terminology
• interoperability
• connectivity
• Over 100 members

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WFMC interfaces

• specifications for process definition data
  interchange
• interfaces to support interoperability b/w
  different workflow systems
• interfaces to support interaction with a variety
  of IT application types
• interfaces to support interaction with user
  interface desktop functions
• interfaces to provide system monitoring and
  metric functions to facilitate the management of
  composite workflow application environments

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Benefits of Workflow Technology

• Organize, schedule, control and monitor process
• Help understand/improve process (analysis,
  simulate, reengineering)
• Reduce paper work
• Support on-line data entry where data originates
  support data exchange and transactions across
  independent enterprises (EDI)
• In most general form, workflow technology can be
  used to support programming-in-the-large

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Web Services
HERMES IST-2000-26429
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Web Services is a new model for using the Web to

• Automatically initiate processes via the Web
  using programs
• Method for describing, publishing initiating
  processes dynamically in a distributed
  environment
• Not necessarily using a Web browser
• Actually, the Web is not required?
• The content- oriented Web is now complimented by
  the service-oriented Web

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Web Services

• If you can imagine a way of electronically
  delivering something
• Of value to a customer
• That will solve a problem, or
• Provide some usefulness
• Then you have a viable example of a Web service

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Some Use Examples

• A service to accept purchase orders (B2B)
• A service for completing tax forms (B2C)
• An insurance policy service to insure the
  products being shipped
• A financing service to ensure payment according
  to vendor terms
• A health-care service to access health-care
  records

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Web Services

• Web services encapsulate business functions
• Check credit card number
• Payment processing
• Stock quotes
• Request for quote, bid processes
• They can be used to compose business processes
• Travel planning
• Health care

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What is a Web Service?

• To put it simply, a Web service is nothing but a
  server that listens for and replies with SOAP
  generally via HTTP

• A Web Service is an interface that describes
• a collection of operations
• that are network accessible
• through standardized XML messaging

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Benefits of a Web service

• Includes
• Decoupling of service interfaces from the
  implementation
• Enabling dynamic service binding
• Providing interoperability among different
  platforms

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These Benefits Derive From

• XML based standards
• Simple Object Access Protocol (SOAP)
• Web Services Description Language (WSDL)
• HTML user-to-machine
• XML/SOAP machine-to-machine

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Web Services

• Existing applications can be wrapped as Web
  services
• Client and Service can use different platforms
  and programming languages
• Services can be composed to make composite
  services

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Web Services

• A Business function made available via Internet
  by a service provider, and accessible by clients
  that could be human users or software
  applications
• World Wide Web Consortiums Web service
  definition
• A software application
• Identified by a URI
• Its interfaces and binding are capable of being
  defined, described and discovered by XML
  artifacts and
• Supports direct interactions with other software
  applications
• Using XML based messages via Internet-based
  protocols

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Web Service Model
Service Registry (ebXML or UDDI) - Web service
descriptions
Discover service
Publish service
Service Consumer
Service Provider - Web service - Service
Description in WSDL
Invoke service through SOAP
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Web Services

• The Web Services Reference Model
• Service Provider
• Service Registry
• Service Consumer
• Major Standards
• WSDL (Web Services Description Language)
• SOAP (Simple Object Access Protocol)
• UDDI (Universal Description, Discovery and
  Integration) registries
• ebXML (Electronic Business XML)

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Why Web Services?

• For B2B interactions, applications need to talk
  to each other on the Web Interoperability is
  needed
• A change in an application should not effect the
  apps it is talking to
• Web services provide these through WSDL and SOAP
• However, the current practice of generating WSDL
  from the code is incorrect because when the code
  changes so does the WSDL
• Yet WSDL is your established public contract with
  the outside world

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Web Services Realities

• Web services are not very efficient
• Dynamic discovery is essential
• Web services infrastructure is easy
• What is difficult is defining domain specific
  ontologies for service discovery

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Web Service Description
Web Service Description
defines
Web Service
Service Consumer
uses
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WSDL Structure
Service
Where to access it
Port (e.g. http//host/svc)
Port
How to access it
Binding (e.g. SOAP, JMS, direct call)
Binding
Operation An Exchange of Messages between a
service Requestor and a Service provider
Abstract definition of the service (set
of Operations)
Abstract interface
portType
operation(s)
inMesage
outMessage
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XML Messaging SOAP

• The current standard for XML Messaging is Simple
  Object Access protocol (SOAP)
• Applications typically communicate with Web
  services via SOAP messaging
• Typically HTTP is used as RPC transport
• XML is used as RPC encoding scheme

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Why SOAP?

• There are a number of wire protocols for RPC
• Internet Inter ORB Protocol for Common Object
  Request Broker Architecture (CORBA)
• Java Remote Method Protocol (JRMP) for Java
  Remote Method Invocation (RMI)
• The key difference between SOAP and these
  protocols are the way they encode data

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Why SOAP?

• Data encoding in RPC involves converting the data
  (integers, character strings or complex objects)
  to be sent to the remote computer executing the
  procedure
• SOAP uses XML for this purpose since it is
  textual, whereas IIOP and JRMP are binary
  protocols
• Using XML for data encoding makes SOAP very user
  friendly for firewalls and for debugging purposes
• Furthermore, the need for specialized software
  such as a CORBA compliant ORB (for IIOP) is not
  needed

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Service Composition Travel Service Example
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How to define Public Processes through Web
Services Web Service Composition

• We had WSFL (Web Services Flow Language) from IBM
  and XLANG from Microsoft
• IBM and Microsoft have agreed to replace them
  with BPEL4WS
• BPEL4WS Business Process Execution Language for
  Web Services

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Business Process Execution Language for Web
Services (BPEL4WS)

• Specifications proposed by IBM, Microsoft, BEA
• Unifies XLANG, WSFL
• XML-based workflow definition language
• Describe business processes that both provide and
  consume web services
• Implemented as an interaction with a web service

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Business Process Execution Language for Web
Services (BPEL4WS)

• BPEL4WS is Complemented by
• WS Coordination specification
• Allows to web services involved in a process to
  share information that links them
• WS Transaction specification
• Allows to monitor the success/failure of each
  coordinated activity
• Reliably cancel the business process
• Involves compensating activities

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Business Process Execution Language for Web
Services (BPEL4WS)

• Business process defines
• Potential execution order of operations (web
  services)
• Data shared between the web services
• Partners involved in business process
• Joint exception handling for collection of web
  services
• Long running transactions between web services

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Thank you for your attention!