UML Sequence Diagrams

Transcription

1 UML Sequence Diagrams Prof. Dr. Eric Dubuis Berner Biel Course "UML and Design Patterns" of module "Software Engineering and Design", version October 2008 BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 1 of 11

2 Session's Goals You'll learn: Syntax of UML sequence diagrams (mostly, some details are omitted) How to express the behavior of a system of objects To apply UML sequence diagrams BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 2 of 11

3 Readings [Fowler]: UML Distilled, Martin Fowler, third ed., Addison-Wesley, ISBN [Jeckle]: UML 2 glasklar, Mario Jeckle et al., 2. Auflage, Hanser Verlag, ISBN See also: [UML-Home]: [UML-Specification]: The readings are not cited in the text that follows. BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 3 of 11

4 Basics The family of UML interaction diagrams includes: sequence diagrams communication diagrams timing diagrams interaction overview diagrams Interaction diagrams describe how groups of objects collaborate. These notes are on UML sequence diagrams. BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 4 of 11

5 An Example anorder:order message anorderline :OrderLine participants aproduct: Product acustomer: Customer calculateprice initial message getquantity getproduct call event life line name / type of participant send event aproduct getpricingdetails time calculatebaseprice calculatediscounts self call action sequence getdiscounts BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 5 of 11

6 Message Types The arrows in UML sequence diagrams carry significant meaning: synchronous message: : Caller : Callee blocked asynchronous message: : Sender : Receiver reply: sender continues BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 6 of 11

7 The Example Modified anorder:order anorderline :OrderLine aproduct: Product acustomer: Customer calculateprice calculateprice getprice(quantity: int) free (unbound) parameter getdiscountedvalue(anorder) bound parameter (~ value) getbasevalue price discountedvalue BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 7 of 11

8 Creating and Deleting Participants ahandler querydatabase creation call execution of constructor (not UML 2) aquery Command creation call querydatabase aquery Statement getresults close object destruction BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 8 of 11

9 Loops Note: Sequence diagrams are not particularly good in expressing loops and conditionals. calculateprice anorder:order anorderline :OrderLine aproduct: Product operator loop guard [for each line item] calculateprice getprice(quantity: int) fragment BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 9 of 11

10 Branching anorder:order careful: Distributor regular: Distributor :Messenger dispatch operator guard alt [value > 100] dispatch guard [else] dispatch combined fragment operator guard opt [needs confirmation] confirm fragment BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 10 of 11

11 Operators of Interaction Frames Operator alt opt par loop critical neg ref sd Meaning Alternative multiple fragments; only one whose condition is true will execute. Optional; the fragment executes only if the given condition is true. Equivalent to an alt with only one fragment. Parallel; each fragment is run in parallel. Loop; the fragment may execute multiple time, and the guard indicates the basis of the iteration. Critical region; the fragment can have only one thread at a time. Negative; the fragment shows an invalid interaction. Reference; refers to an interaction defined in another diagram. The frame is drawn to cover the lifelines involved in the interaction. You can define parameters and a return value. Sequence diagram; used to surround an entire sequence diagram. BFH/TI/Software Engineering and Design/UML and Design Patterns/UML Sequence Diagrams/October 2008/Prof. Dr. E. Dubuis Page 11 of 11