Design. Furthermore, it is natural to discover and change some requirements during the design and implementation work of the early iterations.

Transcription

1 Design

2 Design Iteratively Do the Right Thing, Do the Thing Right. The requirements and object-oriented analysis has focused on learning to do the right thing By contrast, the design work will stress do the thing right; that is, skillfully designing a solution to satisfy the requirements for this iteration. Furthermore, it is natural to discover and change some requirements during the design and implementation work of the early iterations.

3 During Design Logical solution based on the object-oriented paradigm is developed. Heart is the creation of interaction diagrams, which illustrate how objects collaborate to fulfill the requirements. Dynamic object modeling. Creation of interaction diagrams requires the application of principles for assigning responsibilities Design patterns. After or in parallel with drawing interaction diagrams, (design) class diagrams can be drawn. These summarize the definition of the software classes (and interfaces) that are to be implemented in software.

4 Sequence and Communication Diagrams The term interaction diagram is a generalization of two more specialized UML diagram types. sequence diagrams communication diagrams Both can be used to express similar message interactions.

5 Sequence diagrams illustrate interactions in a fence format, in which each new object is added to the right. : A myb : B doone dotwo dothree

6 What might this represent in code? public class A { private B myb = new B(); } public void doone() { myb.dotwo(); myb.dothree(); } //

7 Comunication diagrams illustrate object interactions in a graph or network format, in which objects can be placed anywhere on the diagram doone : A 1: dotwo 2: dothree myb : B

8 Type Strengths Weaknesses Sequence Collaboration clearly show sequence or time ordering of messages simple notation space economical flexibility to add new objects in two dimensions forced to extend to the right when adding new objects; consumes horizontal space difficult to see the sequence of messages more complex notation

9 Sequence Diagram: POS Example : Register : Sale makepayment (cashtendered ) makepayment (cashtendered ) create(cashtendered ) : Payment

10 Communication Diagram: POS Example direction of message makepayment(cashtendered) :Register 1: makepayment(cashtendered) :Sale 1.1: create(cashtendered) :Payment

11 In Rational Rose Create an actor in the use case view and drag it in the sequence diagram. There can t be links from nowhere. Enable Focus of Control. Tools->Options-> For create message drag the arrow to inside Payment.

12 In Rational Rose Create an actor in the use case view and drag it in the communication diagram. There can t be links from nowhere. Disable the default collaboration diagram numbering. Tools->Options->

13 Visual Paradigm for UML

14 Terminology lifeline box representing an unnamed instance of class Sale lifeline box representing a named instance lifeline box representing the class Font, or more precisely, that Font is an instance of class Class an instance of a metaclass :Sale s1 : Sale «metaclass» Font lifeline box representing an instance of an ArrayList class, parameterized (templatized) to hold Sale objects lifeline box representing one instance of class Sale, selected from the sales ArrayList <Sale> collection sales: ArrayList<Sale> sales[ i ] : Sale related example

15 Messages: Left-Right, Right-Left Messages can also go from right to left.

16 Two ways to return values

17 Messages to self or this

18 Frames: Loop To add a loop condition: Right click on the frame From the Pop-up menu choose manage operands Add a constraint such as more items

19 Frames: Conditional Messages

20 Frames: Conditional Messages (UML 1 style)

21 Frames: Mutually Exclusive Conditional Messages

22 Iteration Over a Collection Or we can leave things more implicit like here.

23 How to Relate Interaction Diagrams Select the Interaction use frame Right click and open the specifications. Specify that it refers to another interaction diagram. Close the specifications. Double click on the ref frame. It will open another (empty) diagram. Draw there the authenticate user part. Name this new diagram AuthenticateUser

24 Messages to Classes to Invoke Static (or class) Methods

25 Polymorphic Messages Payment is an abstract superclass, with concrete subclasses that implement the polymorphic authorize operation Payment {abstract} authorize() {abstract}... CreditPayment authorize()... DebitPayment authorize()... polymorphic message object in role of abstract superclass :Register :Payment {abstract} dox authorize stop at this point don t show any further details for this message :DebitPayment :Foo :CreditPayment :Bar authorize doa authorize dox dob separate diagrams for each polymorphic concrete case

26 Communication diagram Examples

27 Links 1: makepayment(cashtendered) 2: foo : Register :Sale 2.1: bar link line msg1 1: msg2 2: msg3 3: msg4 : Register :Sale 3.1: msg5 all messages flow on the same link

28 Messages to self or this msg1 : Register 1: clear

29 Creation Three ways to show creation in a communication diagram create message, with optional initializing parameters. This will normally be interpreted as a constructor call. 1: create(cashier) : Register :Sale 1: create(cashier) : Register :Sale {new} «create» 1: make(cashier) : Register :Sale if an unobvious creation message name is used, the message may be stereotyped for clarity

30 Message Number Sequencing first second third msg : A 1: msg : B 1.1: msg 2.1: msg 2: msg : C fourth 2.2: msg fifth sixth : D

31 Conditional Messages message1 conditional message, with test 1 [ color = red ] : calculate : Foo : Bar unconditional after either msg2 or msg4 : E 1a and 1b are mutually exclusive conditional paths 2: msg6 msg1 1a [test1] : msg2 : A : B 1b [not test1] : msg4 1a.1: msg3 : D 1b.1: msg5 : C

32 Looping runsimulation : Simulator 1 * [ i = 1..n ]: num = nextint : Random iteration is indicated with a * and an optional iteration clause following the sequence number

33 Iteration Over a Collection t = gettotal : Sale 1 * [i = 1..n]: st = getsubtotal lineitems[i]: SalesLineItem this iteration and recurrence clause indicates we are looping across each element of the lineitems collection. This lifeline box represents one instance from a collection of many SalesLineItem objects. lineitems[i] is the expression to select one element from the collection of many SalesLineItems; the i value comes from the message clause. t = gettotal : Sale 1 *: st = getsubtotal lineitems[i]: SalesLineItem Less precise, but usually good enough to imply iteration across the collection members

34 Messages to Classes to Invoke Static (or class) Methods dox message to class, or a static method call : Foo 1: locs = getavailablelocales «metaclass» Calendar

35 Polymorphic Messages polymorphic message stop at this point don t show any further details for this message dox :Register authorize :Payment {abstract} object in role of abstract superclass authorize authorize :DebitPayment doa dob :Foo :CreditPayment dox :Bar separate diagrams for each polymorphic concrete case