Transcript Communication diagrams - School of Engineering and Information

ZEIT2301
Design of Information Systems
Interaction Design:
Communication Diagrams
School of Engineering and Information Technology
UNSW@ADFA
Dr Kathryn Merrick
Topic 07: Interaction Design
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Objectives
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To understand the notation, rules and style guidelines for creating
communication diagrams (previously known as collaboration
diagrams)
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To understand one technique for identifying potential interactions
between objects is a CRUD analysis.
Reference: Text Ch 7
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Communication Diagrams
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Communication diagram – is a behavioural diagram that shows
message passing relationships between objects & actors.
It is equivalent to a sequence diagram, but
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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.
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Communication Diagrams
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Elements of a communication diagram:
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Actors & objects
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Associations & messages – messages are labels on
associations
 Sequence – messages are assigned a sequence number
 Conditions - messages can be conditional
Session 2, 2010
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Communication Diagram Syntax
Session 2, 2010
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Communication Diagram
Session 2, 2010
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Communication Diagram - Rent
Movie
:Rented Items
7 print invoice()
1 find_customer()
3 enter_movie()
5 rent(movie)
6 add(customer, movies)
8 generateRentalTotal()
Object
2 search(CustId)
:Check-out
Manager
:Customer
:Employee
4 searchBarcode()
:Inventory
Message
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CRUD: an analysis technique
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One technique for identifying potential interactions between objects is
a CRUD analysis.
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CRUD stands
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C: create
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R: read (or reference)
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U: update
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D: delete
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What object creates,
reads, updates,
deletes another
object?
Use a CRUD matrix …
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Sample CRUD Matrix
An object of the receptionist class needs to be able to Create,
Read, Update and Delete objects of the Patient class.
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Summary
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Behavioural Modelling
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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
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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.
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