Task-Oriented, Policy Driven Business Requirements for Web ...

Task-Oriented, Policy Driven Business Requirements for Web ...

Task-Oriented Business Requirements Elicitation for Web Services Stephen Gorton IST-FET IST-2005-16004 Department of Computer Science, University of Leicester, University Road, Leicester LE1 7RH Web Service Architecture Composition often the top layer; R eeq q u iu r ei m tse n t s R r een m Composition and orchestration still a blur! Exportable service Software service Software Composite Composite service service Little regard for a more abstract requirements layer.

service service service service UDDI, WSDL, etc. UDDI, WSDL, etc. HTTP, HTTPS, SMTP, etc. HTTP, HTTPS, SMTP, etc. BCTCS 05/04/06 Task-Oriented, Policy Driven Business Req uirements for Web Services 2 Current Solutions 1 Approach 1: Composition as Requirements BPEL: DAML-S Code snippets taken from Milanovic and Malek: Current Solutions for Web Service Composition. IEEE Internet Computing, Nov/Dec 04 BCTCS 05/04/06

Task-Oriented, Policy Driven Business Req uirements for Web Services 3 Current Solutions 2 Approach 2: Specialised Requirements Language BPMN: B A + + C UML: B A C BCTCS 05/04/06 Task-Oriented, Policy Driven Business Req uirements for Web Services 4 Wedding Example Business goal g = plan wedding; Broken down into objectives (composite tasks): ct1 = plan pre-wedding celebrations;

ct2 = plan preparations; ct3 = plan legalities; ct4 = plan ceremony; ct5 = plan post-ceremony celebrations; ct6 = plan honeymoon. Tasks are arranged according to result timeline, not according to execution timeline! e.g. ceremony and post-ceremony celebrations often planned in parallel. Policies: The entire event should not cost more than 10k; The ceremony and post-ceremony celebrations should be on the same day; The honeymoon should be booked through a known and trusted travel agency. BCTCS 05/04/06

Task-Oriented, Policy Driven Business Req uirements for Web Services 5 Booking the Honeymoon 1 Flows: start Control runs from start to finish; Solid lines indicate control flow routes; A task is executed when control reaches it; Control proceeds when the task has finished. t1 t2 Flow Split: FS: in -> OUT; Control proceeds down each output simultaneously; No limit on number of output

flows; Parallel split workflow pattern t3 2 t4 Conditional Merge: CM: IN -> out; Forces synchronisation; Mandatory and optional flows; Specifies minimum number of flows; Discriminator workflow pattern. BCTCS 05/04/06 t5 t6 t7 2 Task-Oriented, Policy Driven Business Req uirements for Web Services 6

Booking the Honeymoon 2 Strict Preference: SP: in -> out; Input is a set of pairs {t, n} t is a task; n is a priority rating; t8 New workflow pattern. Flow Merge: FM: IN -> out; Incoming set of control flows contains only one active flow; No synchronisation issue; (Multiple) Merge workflow pattern. t9 t11 t10

t12 p1 c1 Random Choice: RC: in -> out; All tasks invoked; When a first gets to a commit, all others are cancelled; New workflow pattern. BCTCS 05/04/06 Task-Oriented, Policy Driven Business Req uirements for Web Services end 7 Other Notation Flow Junction Operator:

fx FJ: in -> {out1, out2}; Left output is primary; Output flow chosen according to a test; Exclusive choice workflow pattern. test fx.1 fx.2 Bounded cycles allowed: For both composite and atomic tasks; Can be modelled with flow junction and flow merge. (since we only allow one control flow input, a flow merge function should be used). BCTCS 05/04/06 ti n Task-Oriented, Policy Driven Business Req uirements for Web Services 8

Summary Current notations not appropriate: UML has some merits but does not support many workflow patterns; BPMN is the nearest to a complete solution; None allow for the expression of all requirements. A simple graphical notation: Describing process flows; Scope for core and non-core (non-functional) requirements; Offers the context in which policies are used. Further work: Workflow patterns (data and resource patterns); Policies and policy framework at the business level; A workbench. BCTCS 05/04/06 Task-Oriented, Policy Driven Business Req uirements for Web Services 9 Thank you. Any Questions? BCTCS 05/04/06 Task-Oriented, Policy Driven Business Req uirements for Web Services 10

Recently Viewed Presentations

  • 核融合発電の早期実現について

    核融合発電の早期実現について

    Our possible target for 1st commercial plant: COEn<1.5 In the LDNE21 model, the break even COE at the introduction year is assumed and the COE will be reduced by a rate of 2.3%/y for the initial 25 years. The maximum...
  • Informal tú commands - Sra. Bernal

    Informal tú commands - Sra. Bernal

    Informal Commands Hablar Habla s Los Irregulares venir = ven decir = di salir = sal hacer = haz tener = ten ir = ve poner = pon ser = sé (mantener= mantén) Ven di sal haz ten ve pon...
  • A Brief Introduction to Configuration Management Guozheng Ge

    A Brief Introduction to Configuration Management Guozheng Ge

    A Brief Introduction to Configuration Management Guozheng Ge ([email protected]) Computer Science Dept., UC Santa Cruz*
  • The Color Wheel

    The Color Wheel

    To the human eye, orange is a very hot color, so it gives the sensation of heat. Nevertheless, orange is not as aggressive as red. Orange increases oxygen supply to the brain, produces an invigorating effect, and stimulates mental activity....
  • Chapter 2 part #4 Operator

    Chapter 2 part #4 Operator

    Division Example. Exampleof division issues: 10 / 3 gives 3. 10.0 / 3 gives 3.33333. As we can see, if we divide two integers we get an integer result. if one or both operands is a floating-point value we get...
  • Gastrointestinal System - Weebly

    Gastrointestinal System - Weebly

    Cardiovascular System. Sinoatrial (SA) Node: upper portion of right atrium; called the "pacemaker" of the heart as it has the ability to initiate the heartbeat without external nerve stimulation
  • 2014 AFSA Tax Clinic Training - Eric Fong

    2014 AFSA Tax Clinic Training - Eric Fong

    The only line that your client will probably care about. ... You can also find this ONLINE on the NSLSC website. Union/Professional Dues (Deduction) Union dues normally already recorded on T4. ... 2014 AFSA Tax Clinic Training Last modified by:
  • 30 For years, Oxford Tutorial College has been

    30 For years, Oxford Tutorial College has been

    30+ years in education with a focus on teaching, managing and looking after students' well being and safety. ... One-stop 'hub' for students. ... University of Leeds . University of Surrey. University of East Anglia. University of Birmingham. University of...