1 / 29

Dynamic Modeling

Dynamic Modeling. Dynamic Modeling with UML. Interaction diagram Dynamic behavior of a set of objects arranged in time sequence Interaction between objects State Chart diagram A state machine that describes the response of a given class to the receipt of outside stimuli

tirzah
Download Presentation

Dynamic Modeling

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Dynamic Modeling

  2. Dynamic Modeling with UML • Interaction diagram • Dynamic behavior of a set of objects arranged in time sequence • Interaction between objects • State Chart diagram • A state machine that describes the response of a given class to the receipt of outside stimuli • Behavior of a single object

  3. Sequence Diagram • From flow of events in use case, go to sequence diagram • Graphical description of objects in use case • Classes have already been found, but finds new classes • Each event passes a message between a sender object and a receiver object

  4. Example • Establish connection between smart card and onboard computer • Establish connection between onboard computer and sensor for seat • Get current seat position and store on smart card

  5. Sequence Diagram for “Get SeatPosition” Seat Onboard Computer Smart Card • 1. Establish connection between smart card and onboard computer • 2. Establish connection between onboard computer and sensor for seat • 3. Get current seat position and store on smart card Establish Connection Establish Connection Accept Connection Accept Connection Get SeatPosition “500,575,300” time

  6. Heuristics for Sequence Diagrams • Layout: • 1st column: Should correspond to the actor who initiated the use case • 2nd column: Should be a boundary object • 3rd column: Should be the control object that manages the rest of the use case • Creation: • Control objects are created at the initiation of a use case • Boundary objects are created by control objects

  7. Access: • Entity objects are accessed by control and boundary objects, • Entity objects should never call boundary or control objects: This makes it easier to share entity objects across use cases and makes entity objects resilient against technology-induced changes in boundary objects.

  8. Is this a good Sequence Diagram? Seat Onboard Computer Smart Card • First column is not the actor • It is not clear where the boundary object is • It is not clear where the control object is Establish Connection Establish Connection Accept Connection Accept Connection Get SeatPosition “500,575,300”

  9. :Tournament :Arena :League Boundary League Owner newTournament (league) :Announce «new» Tournament Control checkMax Tournament() setName(name) setMaxPlayers (maxp) create Tournament (name, maxp) commit() createTournament (name, maxp) «new» :Tournament An ARENA Sequence Diagram : Create Tournament

  10. Impact on ARENA’s Object Model • Let’s assume, before we formulated the previous sequence diagram, ARENA’s object model contained the objects • League Owner, Arena, League, Tournament, Match and Player • The Sequence Diagram identified new Classes • Tournament Boundary, Announce_Tournament_Control

  11. League Owner League 1 * Attributes Attributes Operations Operations Tournament Attributes Operations Player Match * * Attributes Attributes Operations Operations

  12. Tournament_ Boundary Announce_ Tournament_ Control Attributes Operations Attributes Operations League Owner League 1 * Attributes Attributes Operations Operations Tournament Attributes Operations Player Match * * Attributes Attributes Operations Operations

  13. Impact on ARENA’s Object Model (ctd) • The Sequence Diagram also supplied us with a lot of new events • newTournament(league) • setName(name) • setMaxPlayers(max) • Commit • checkMaxTournaments() • createTournament

  14. Question: Who owns these events? • Answer: For each object that receives an event there is a public operation in the associated class. • The name of the operation is usually the name of the event.

  15. :Tournament :Arena :League Boundary League Owner newTournament (league) :Announce «new» Tournament Control checkMax Tournament() setName(name) setMaxPlayers (maxp) create Tournament (name, maxp) commit() «new» :Tournament Example from the Sequence Diagram createTournament is a (public) operation owned by Announce_Tournament_Control createTournament (name, maxp)

  16. Tournament_ Boundary Attributes Operations League Owner League 1 * Attributes Attributes Operations Operations Tournament Announce_ Tournament_ Control Attributes Operations Attributes createTournament (name, maxp) Player Match * * Attributes Attributes Operations Operations

  17. What else can we get out of sequence diagrams? • Sequence diagrams are derived from the use cases. We therefore see the structure of the use cases. • The structure of the sequence diagram helps us to determine how decentralized the system is. • We distinguish two structures for sequence diagrams: Fork and Stair Diagrams (Ivar Jacobsen)

  18. Fork Diagram • Much of the dynamic behavior is placed in a single object, ususally the control object. It knows all the other objects and often uses them for direct questions and commands.

  19. Stair Diagram • The dynamic behavior is distributed. Each object delegates some responsibility to other objects. Each object knows only a few of the other objects and knows which objects can help with a specific behavior.

  20. Fork or Stair? • Which of these diagram types should be chosen? • Object-oriented fans claim that the stair structure is better • The more the responsibility is spread out, the better • However, this is not always true. Better heuristics:

  21. Decentralized control structure • The operations have a strong connection • The operations will always be performed in the same order • Centralized control structure (better support of change) • The operations can change order • New operations can be inserted as a result of new requirements

  22. UML Statechart Diagram Notation Event trigger With parameters State1 State2 Event1(attr) [condition]/action do/Activity Guard condition entry /action exit/action Also: internal transition and deferred events

  23. Notation based on work by Harel • Added are a few object-oriented modifications • A UML statechart diagram can be mapped into a finite state machine

  24. Statechart Diagrams • Graph whose nodes are states and whose directed arcs are transitions labeled by event names. • We distinguish between two types of operations in statecharts: • Activity: Operation that takes time to complete • associated with states • Action: Instantaneous operation • associated with events • associated with states (reduces drawing complexity): Entry, Exit, Internal Action

  25. A statechart diagram relates events and states for one class • An object model with a set of objects has a set of state diagrams

  26. State • An abstraction of the attributes of a class • State is the aggregation of several attributes a class • Basically an equivalence class of all those attribute values and links that do no need to be distinguished as far as the control structure of the system is concerned • Example: State of a bank • A bank is either solvent or insolvent • State has duration

  27. coins_in(amount) / set balance Collect Money Idle coins_in(amount) / add to balance cancel / refund coins [item empty] [select(item)] [change<0] do: test item and compute change [change>0] [change=0] do: dispense item do: make change Example of a StateChart Diagram

  28. Headlight Off power power on off On Toy Car: Dynamic Model Wheel Forward power power off on Stationary Stationary power power on off Backward

  29. State Chart Diagram vs Sequence Diagram • State chart diagrams help to identify: • Changes to an individual object over time • Sequence diagrams help to identify • The temporal relationship of between objects over time • Sequence of operations as a response to one or more events

More Related