Interaction Diagrams
PB007 Software Engineering I
Bruno Rossi
05. 12. 2016
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Interaction Diagrams
Interaction diagrams model the cooperation of classes/objects/actors for
the implementation of use cases (or parts of them).
We distinguish 4 main types, each of which gives a view of a different
aspect of the interaction:
1. Sequence diagrams capture the communication between
classes/objects with an emphasis on the temporal sequence when passing
messages.
2. Communication diagrams capture communication with an emphasis
on relationships between classes/objects.
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Interaction Diagrams II
3. Timing diagrams model time constraints of the interactions of objects
in real time.
4. Interaction overview diagrams are a special case of activity
diagrams, which show a top view of the connections between the complex
sub-interactions.
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Sequence diagram
Sequence diagrams show the interaction as a time-ordered sequences of
messages between objects/classes/actors.
Basic elements:
Actors, classes, objects
Lifelines
Activations (focus of control)
Messages
Combined Fragments
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Sequence diagram - Example
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Sequence diagram - Example II
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Sequence diagram - Combined Fragments
Combined fragments divide the sequence diagram in more areas with
different behavior.
Each combined fragment is marked with an oper´ator, one or more
operands, and condition(s).
The most important operators are:
opt (option) - has one operand, which is triggered only if the defined
condition is met
alt (alternatives) - the operand whose condition is evaluated to true
will be launched.
loop - repeated execution of the operand
break - operand is executed if it meets any conditions and terminates
the execution cycle
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Sequence diagram - Combined Fragments II
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Sequence diagram - Combined Fragments III
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Communication Diagram
Communication Diagrams capture the interactions of objects/classes
that communicate with each other.
The basic elements:
Actors, classes, objects
connections (links)
Messages
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Communication Diagram - Example
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Communication Diagram - Iterations
Iterations are expressed in communication diagram using the iteration
expression.
Syntax: * [loop min, max [condition]]
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Communication Diagram - Branching
Branching in the communication diagram is obtained by adding guarding
conditions to communications. The message is sent only in case that the
condition evaluates to true.
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Tasks
Open the use case model and the classes and for each use case look
at the objects that are involved in the various functionalities
Select the 5 most interesting (sufficiently complex) use cases
Model 2 of them (the simpler ones) by means of a communication
diagram
Model the remaining 3 by means of sequence diagrams
When modelling the interaction diagrams, update the class diagram
with operations that might be necessary
Upload the PDF report into folder (Week 10).
Deadline: Saturday, 10.12.16 23:59
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Customization of PDF Reports
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