Sequence Diagram - Message Notation

This section describes the Message Notation used in a UML Sequence Diagram. A Message Notation represents a particular communication between objects participating a communication interchange.

A Message Notation is a graphical notation used in a UML Sequence Diagram to represent a particular communication between objects participating a communication interchange.

A Message Notation is drawn as a straight line with an arrow pointing to the lifeline which receives the message. The style of the line and arrow have 3 variations depending on whether or not the message is synchronous message:

A Message Notation should be draw from the lifeline of the sender to the lifeline of the receiver. If the sender or receiver is unknown or simply outside of the scope of the diagram, a small solid circle should used:

A Message Notation may have a label to provide message name and arguments. An order may support 2 message calls: A synchronous message call of GetOrder(id) and an asynchronous call of CancelOrder(id). These message calls can be drawn as Message Notations in a UML sequence diagram as shown below:
UML Notation Shape - Message

Last update: 2014.

Table of Contents

 About This UML Tutorial Book

 Introduction of UML (Unified Model Language)

 UML Class Diagram and Notations

 UML Activity Diagram and Notations

UML Sequence Diagram and Notations

 What Is a Sequence Diagram?

 Sequence Diagram - Lifeline Notation

Sequence Diagram - Message Notation

 Sequence Diagram - Execution Specification Notation

 Sequence Diagram - Frame Notation

 UML State Machine Diagram and Notations

 UML Use Case Diagram and Notations

 MS Visio 2010 - UML Drawing Tool

 References

 PDF Printing Version