Csse3002 Tuesday 2 For process modelling, Jeff the ninja - PowerPoint PPT Presentation

Csse3002 Tuesday 2 For process modelling, Jeff the ninja recommends... Little-JIL

Overview  What is Little-JIL?  Jared  Why use Little-JIL?  Douglas  Interrupt if you have a question

What is Little-JIL?  Research at UMass  Process modelling language  Co-ordination of agents  Formal semantics  Graphical representation

Process modelling language  Some formal languages are object-based  UML, B  create abstract data types & methods  “what is an X, and what can you do with it?”  Little-JIL is process-based  break complex algorithms into pieces  “how do you do X, and who is involved?”

Co-ordination of agents  Co-ordination of agents  scheduling of tasks  communication between agents

Little-JIL process model  Composed of s teps  Steps are executed by agents  Steps have badges which labels are attached to

Example

Example agent:Jared Pass Csse3002

Example agent:Jared Step name Agent executing Pass Csse3002 the step

Example agent:Jared Pass Csse3002

Example agent:Jared Pass Csse3002 Do assignment 3 Do essay

Example Steps executed in parallel agent:Jared Pass Csse3002 Do assignment 3 Do essay

Example agent:Jared Pass Csse3002 Do assignment 3 Do essay

Example agent:Jared Pass Csse3002 Do essay Do assignment 3

Example agent:Jared Pass Csse3002 Do essay Do assignment 3 agent:Douglas agent:Lawrence Choose topic Write content

Example agent:Jared Pass Csse3002 Sequential execution (left to right) Do essay Do assignment 3 Steps assigned to different agents agent:Douglas agent:Lawrence Choose topic Write content

Example agent:Jared Pass Csse3002 Do essay Do assignment 3 agent:Douglas agent:Lawrence Choose topic Write content

Example agent:Jared Pass Csse3002 Do assignment 3 agent:Douglas agent:Lawrence Do essay Choose topic Write content

Example agent:Jared Pass Csse3002 Do assignment 3 agent:Douglas agent:Lawrence Do essay Choose topic Write content Cheat Do it properly

Example agent:Jared Pass Csse3002 Choose Do assignment 3 agent:Douglas agent:Lawrence Do essay Choose topic Write content Cheat Do it properly

Example agent:Jared Pass Csse3002 Do assignment 3 agent:Douglas agent:Lawrence Do essay Choose topic Write content Cheat Do it properly

Example agent:Jared Pass Csse3002 Do essay Do assignment 3 agent:Lawrence agent:Douglas Choose topic Write content Do it properly Cheat

Example agent:Jared Pass Csse3002 Do essay Do assignment 3 agent:Lawrence agent:Douglas Choose topic Write content Do it properly Cheat Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Do essay Do assignment 3 agent:Lawrence agent:Douglas Choose topic Write content Do it properly Cheat T ry (execute sequentially until one succeeds) Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Do assignment 3 Do essay agent:Douglas agent:Lawrence Choose topic Write content Cheat Do it properly Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Do assignment 3 Do essay agent:Douglas agent:Lawrence chosenT opic Choose topic Write content Value passed between steps Cheat Do it properly Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Do assignment 3 Do essay agent:Douglas agent:Lawrence chosenT opic Choose topic Write content Cheat Do it properly Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Do assignment 3 Do essay agent:Douglas agent:Lawrence chosenT opic Exception declared Choose topic Write content x CantT akeItAnymore Cheat Do it properly Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Exception rethrown Do assignment 3 Do essay agent:Douglas agent:Lawrence chosenT opic Choose topic Write content ↑CantT akeItAnymore x CantT akeItAnymore Cheat Do it properly Copy from friend Bribe David Carrington

Example agent:Jared Pass Csse3002 Exception handled StudyArtsAtGriffith Do assignment 3 Do essay agent:Douglas agent:Lawrence chosenT opic Choose topic Write content ↑CantT akeItAnymore x CantT akeItAnymore Cheat Do it properly Copy from friend Bribe David Carrington

Little-JIL features  Co-ordination of agents  scheduling of tasks  communication between agents

Little-JIL features  Co-ordination of agents  Already covered  Step sequencing  parallel  sequential  choose  try  Parameter passing  Exception handling

Little-JIL features  Co-ordination of agents  Not yet covered  step repetition  conditional execution  deadlines  pre-conditions & post-conditions  resource acquisition  communication between groups of agents  multi-way  synchronous & asynchronous

Little-JIL features  Co-ordination of agents  Is this useful?

Why?  Why use Little-JIL?  Why use a process modelling language?

Design goals  Simplicity  Expressiveness  Precision  Flexibility

Simplicity  Graphical  No data types, data definition, calculation...

Expressiveness  ‘A picture is worth a thousand words’ - Ole Canadian Proverb* *Not actually Canadian

Expressiveness  ‘A picture is worth a thousand words’ agent:ThirstyPerson Get drink NotCold IsCold Get coke Get milk

Precision  Strict syntax & semantics

Flexibility  Any process can be described

Little-JIL’s limitations  Assumes agent knowledge  Is this valid?  Doesn’t get requirements  Doesn’t run testing  Doesn’t write code  So what’s the use??

Possible uses  Modelling The Software Process TM  Specification for system-wide process flows

Modelling the software process  Gantt chart & PERT chart & Little-JIL  Concurrency  Dependencies  Time  Little-JIL  Better sequencing (choice & try)  Exceptions  Communication

Software specification  Combines good aspects of  UML activity/collaboration/sequence diagrams  Multi-agent  Communication  Flowcharts  Sequencing of steps  Decisions

Software specification (cont)

Software specification (cont) agent:User Add action item ✓ MaxItemsExceeded ↲ InvalidName x MaxItemsExceeded x InvalidName Clear form Enter information

Software specification (cont)  Problems  No data  No calculation

Conclusion  Can Little JIL help?  Yes  Good replacement for UML sequence, activity and collaboration diagrams  Good for explaining processes within software engineering  But  Relies on human interpretation  No data types  Relies on agent ability

References  Sutton, Lerner, & Osterweil “Experience using the JIL process programming language to specify design processes” (1997)  Sutton & Osterweil “The design of a next- generation process language” (1997)  Cass, Lerner, et al “Little-JIL/Juliette: a process definition language and interpreter” (2000)  LASER process working group “Little-JIL 1.5 language report” (2006)

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