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Session

Communication Diagram

Checklist

Explain Communication Diagram

Example of Communication Diagram

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Communication

Diagram

Communication diagrams are used to denote interaction between objects. They follow the

same rule as to what sequence diagram does. Communication diagram helps us to shows

interactions in a modular level. In my opinion it’s better to use sequence diagram (whose syntax

is known by everyone) rather than using communication diagrams (which is not so popular).

However communication diagrams are the best when it comes to represent links between

objects. There are no special syntax for constructing communication diagram but there are

couple things to remember when using communication diagram.

I have constructed a communication diagram for a software update process. There are three

objects – Software Update, Local Update and Install. Software update object gets triggered

when there is a need for update. Software update then checks for any local update is available.

If local updates are available Install object instance is created and update is installed.

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Figure 1: Software Update - Communication Diagram

Participants in Interaction : Objects that are part of interaction

Link Type : Represents relationship between objects.

<<Create>>, <<destroy>>, <<links>> are some of the

predefined stereotype used as link type.

Message : Messages informs us how objects are interacting between

each other

Sequence Number : Sequence Number (1.0, 1.1, 1.2, and 2.0) denote sequence

in which the objects interact. We can track the flow of the

system using these sequence numbers

Note: There is a UML standard format for specifying

sequence number kindly refer to that for correct

numbering.

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Review

Communication diagram are used to represent links between objects

They help us to understand how objects interact with each other in a

System