Overview

The following is a summary of the steps you perform to use sequence diagrams to describe the interactions between objects:

1. Create a sequence diagram under the Use-Case Realization
2. Place the participating objects and actors in the sequence diagram
3. Describe the messages between the objects
4. Describe what an object does when it receives a message

For more details about sequence diagrams, see:

• Sequence Diagrams (Overview) topic in the Rational Rose online help.

• Chapter 4, Introduction to Diagrams and Chapter 9, Interaction Diagrams and Specifications in the Using Rational Rose manual.

1. Create a sequence diagram under the Use-Case Realization

When you create a sequence diagram for a use case realization, consider naming the diagram "<use-case name> - <flow type>". This naming convention simplifies future tracing of objects to the use-case realization that they participate in. Also, use the documentation window to enter a brief description of the scenario that the sequence diagram depicts.

2. Place the participating objects and actors in the sequence 
diagram

One of the primary elements of a sequence diagram is an object. An object has state, behavior, and identity. The structure and behavior of similar objects are defined in their common class. Each object in a diagram indicates some instance of a class. An object that is not named is referred to as a class instance. In this step, you:

• Drag and drop actors onto the sequence diagram.

• Add objects to the diagram and identify the classes to which the objects belong.

3. Describe the messages between the objects

A message represents the communication between actors and objects, indicating that an action will follow. It carries information from the source focus of control to the destination focus of control. In a sequence diagram a message icon represents exactly one message. When you create a message, use the documentation field in the Message Specification to describe the message.

4. Describe what an object does when it receives a message

To enhance a message, you can attach a script to it. Use the Text Box symbol in the sequence diagram toolbar.