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ZEIT2301 Design of Information Systems Interaction Design: Communication Diagrams. School of Engineering and Information Technology UNSW@ADFA Dr Kathryn Merrick. Topic 07: Interaction Design. Objectives
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ZEIT2301Design of Information SystemsInteraction Design: Communication Diagrams School of Engineering and Information Technology UNSW@ADFA Dr Kathryn Merrick
Topic 07: Interaction Design • Objectives • To understand the notation, rules and style guidelines for creating communication diagrams (previously known as collaboration diagrams) • To understand one technique for identifying potential interactions between objects is a CRUD analysis. Reference: Text Ch 7
Communication Diagrams Communication diagram – is a behavioural diagram that shows message passing relationships between objects & actors. It is equivalent to a sequence diagram, but Communication diagram - emphasizes the flow of messages through a set of objects, Sequence diagram – emphasizes the time ordering of messages The analyst/designer may choose either or both. 3
Communication Diagrams Elements of a communication diagram: Actors & objects Associations & messages– messages are labels on associations Sequence – messages are assigned a sequence number Conditions - messages can be conditional Session 2, 2010 4
Communication Diagram Syntax Session 2, 2010 5
Communication Diagram Session 2, 2010 6
Communication Diagram - Rent Movie :Rented Items Object 1 find_customer() 6 add(customer, movies) 3 enter_movie() 8 generateRentalTotal() 5 rent(movie) 2 search(CustId) :Check-out Manager :Customer 7 print invoice() :Employee 4 searchBarcode() :Inventory Message 7
CRUD: an analysis technique One technique for identifying potential interactions between objects is a CRUD analysis. CRUDstands C: create R: read (or reference) U: update D: delete Use a CRUD matrix … What object creates, reads, updates, deletes another object? What object creates, reads, updates, deletes another object? 8
Sample CRUD Matrix An object of the receptionist class needs to be able to Create, Read, Update and Delete objects of the Patient class. 9
Summary Behavioural Modelling State Machine diagrams – shows the different states that an object of a single class passes through during its life in response to events. Can also be used at a higher level to explore the complex behaviour of a system or component, particularly real-time systems. Interaction Diagrams Sequence diagram – illustrates the objects that participate in a use case and the messages that pass between them. Emphasis on the time ordering of messages sent. Communication diagram – equivalent to sequence diagrams (i.e. objects & messages), but emphasis on the flow of control between objects. 10