Introduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of

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1 Introduction to Software Engineering (2+1 SWS) Winter Term 2009 / 2010 Dr. Michael Eichberg Vertretungsprofessur Software Engineering Department of Computer Science Technische Universität Darmstadt

2 Dr. Michael Eichberg Fachgebiet Software Engineering Department of Computer Science Technische Universität Darmstadt Introduction to Software Engineering UML Interaction Diagrams

3 UML Interaction Diagrams 3 Interaction diagrams are used to visualize the interaction via messages between objects; they are used for dynamic object modeling. Repetition

4 The UML offers four types of interaction diagrams. UML Interaction Diagrams 4 Sequence diagrams (which use a fence format) Communication diagrams (which use a graph or network format) Timing diagrams (not discussed any further) Interaction overview diagrams (not discussed any further) do1 Repetition :A 1: do2 2: do3 myb:b

5 Dr. Michael Eichberg Fachgebiet Software Engineering Department of Computer Science Technische Universität Darmstadt Introduction to Software Engineering UML Communication Diagrams

6 Links and Messages in Communication Diagrams UML Communication Diagrams A link is a connection path between two objects (it is an instance of an association) A link indicates some form of navigation and visibility between the objects is possible. 6 Each message between objects is represented with a message expression and a small arrow indicating the direction of the message Sequence numbers are added to show the sequential order of messages in the current thread of control; the starting message is often not numbered. makepayment :Register 1: makepayment(cashtendered) 2: gettaxes 2.1. getdate :Sale

7 Links and Messages in Communication Diagrams UML Communication Diagrams 7 Modeling self messages makepayment :Register 1: verify

8 Alternative Notations for Modeling Instance Creation Create message, with optional initializing parameters. This will normally be interpreted as a constructor call. UML Communication Diagrams 8 :Register 1: create(cashier) :Sale :Register 1: create(cashier) :Sale{new} :Register «create» 1: make(cashier) :Sale If an unobvious creation message name is used, the message may be stereotyped for clarity.

9 Message Number Sequencing The initial message ist not numbered to make the numbering easier to comprehend. UML Communication Diagrams 9 second message third message i_msg 1: j_msg :A :B first message 2: n_msg 1.1: k_msg 2.1: l_msg :C fifth message forth message 2.2: m_msg :D sixth message

10 Modeling Conditional Messages UML Communication Diagrams 10 :E 2: msg6 Small letters are sometimes used to mark methods that are executed in parallel. msg 1a [test1]: msg2 :A :B 1b [not test1]: msg4 1a.1: msg3 :D 1b.1: msg5 :C The message is only sent if the condition evaluates to true. The condition is written in square brackets. In case of modeling mutually exclusive message conditional path letters are prepended.

11 Iterating (Convention only; this is not official UML.) UML Communication Diagrams 11 t = gettotal :Sale 1*[i=1..n]:st = getsubtotal lineitems[i] : SalesLineItem * [...] indicates iteration.

12 Messages to Class Objects UML Communication Diagrams 12 makepayment :Sale 1: locs = getavailablelocales «metaclass» Calendar e.g. to format the date as either 3/2/2009 or

13 Example of an UML like Communication Diagram UML Communication Diagrams : create "Main Program" ppi:processpointcutinterpreter create sc_pcd:pointcut create 0.1: create 0.2: create if_pcd:pointcut create and_pcd:pointcut pi:processinterpreter seci:securityinterpreter 1.0: create ([pi,seci,ppi]) 2.0: "aspect"(params:map,asbody:closure) 1.3.1: declarejoinpoint ( class:string, method:string, jpreifier:closure ) 3.0: "process"(params:map,processbody:closure) Not valid UML! 1.3: setmetaclass (ccc) 1.1: setmetaclass (ccc) ccc:cccombiner 3.1: "process"(params,processbody:closure) 1.2: setmetaclass (ccc) 2.1: create(params:map) 2.2:setDelegate(ccc) 2.3: call standard method call calls using the MOP : "service_call"(«context: regex: String») : "if_pcd"(«context: ifbody:closure») : "&"(«Context: service_call_pcd, if_pcd») a:aspect : addadvice(and_pcd,advbody) : setdelegate(ccc) advbody:closure asbody:closure 2.3.1: invokemethod("service_call", «Context: regex: String») 2.3.2: invokemethod("if_pcd", «Context: ifbody:closure») 2.3.3: invokemethod("&", «Context: sc_pcd, if_pcd») 2.3.4: invokemethod("around", «Context: and_pcd, advbody:closure»)

14 Dr. Michael Eichberg Fachgebiet Software Engineering Department of Computer Science Technische Universität Darmstadt Introduction to Software Engineering UML Communication vs. UML Interaction Diagrams

15 Strengths and Weaknesses Interaction Diagrams UML Interaction Diagrams 15 Type Strengths Weaknesses Sequence Diagram clearly shows sequence or time ordering of messages large set of detailed notation options - forced to extend to the right when adding new objects; consumes horizontal space Communication Diagram space economical - flexibility to add new objects in two dimensions - more difficult to see sequence of messages - fewer notation options

16 Strengths and Weaknesses Interaction Diagrams UML Interaction Diagrams 16 Type Strengths Weaknesses Sequence clearly shows sequence or time ordering of messages large set of detailed notation options - forced to extend to the right when adding new objects; consumes horizontal space UML tools often emphasize sequence diagrams, because of their greater notational power. Communication space economical - flexibility to add new objects in two dimensions - more difficult to see sequence of messages - fewer notation options