Message (Sequence Diagram)

d_message

 

Sequence diagrams depict work flow or activity over time using Messages passed from element to element. These Messages correspond in the software model to Class operations and behavior. When you display a Sequence diagram, the Diagram Toolbox automatically switches to the Interaction Toolbox pages, containing the Message icon.

Access     Click on the Message icon, click on the source object and drag the cursor to the target object
(If the Message Properties dialog does not display, right-click on the Message and on the Message Properties menu option)

Create a Message on a Sequence diagram

Field/Option/Button

Action

See also

Message

Type the Message name.

If the Message flow is towards a Class element (dropped in from a Class diagram) or a Lifeline element having a classifier, and the destination Class has defined operations, you can click on the drop-down arrow and select an appropriate operation name; the Message then reflects the destination Class operations.

You can also include operations that the element's classifier has inherited, in the list. To do this, select the Show Inherited Methods checkbox (below).
 

 

Class Element

Lifeline

Operations

If the available operations on the destination Class are not appropriate, click on this button and define a new operation in the destination element, using the Operations dialog.

If you create a Message without making reference to the target Class operations, no new operation is added to the target Class.

 

General Properties of Operations

Parameters

Type any parameters that the Message has, as a comma-separated list.

 

 

Argument(s)

(Optional) Type the actual value that corresponds to each parameter, as a comma-separated list.

 

 

 

Return Value

If the Message has a return value or type, specify it in this field.

 

 

Show Inherited Methods

Select this checkbox to include operations that the destination element's classifier has inherited, in the drop-down list of operations available in the Message field.

Clear the checkbox to show only operations from the classifier itself.

 

 

Assign to

If the Message flow is from a Class element or Lifeline element with classifier that has defined attributes, click on the drop-down arrow and select an appropriate attribute name.

The Message reflects the attributes from the source Class; you cannot add further attributes to the source Class here - if no appropriate attribute is listed, open the Class element Properties dialog and add the required attribute.

Otherwise, optionally type the name of the object to assign the message flow to.

 

 

Stereotype

(Optional) Type or select a stereotype for the connector (this is displayed on the diagram, if entered).

 

 

Alias

(Optional) Type an alias for the name of the Message.

On the diagram, the alias displays if the Use Alias if Available checkbox is selected on the Diagram tab of the Diagram Properties dialog.

The Alias displays instead of or as well as the Message name, depending on the setting selected in the Alias Usage panel of the Diagram Behavior page of the Options dialog.

 

 

Diagram Behavior Options

Condition

Type any conditions that must be true in order for the Message to be sent.

 

 

Constraint

Type any constraints that might exist on when the Message is sent.

 

 

Is Iteration

Select the checkbox to indicate that the Message will iterate until the specified condition takes the value false. The condition statement on the diagram is prefixed by an asterisk (*).

Clear the checkbox to indicate that the Message will only be sent once within the process cycle, if the specified condition is true.

 

 

Start New Group

(For Communication diagram Messages). Select this checkbox to reset the Message (and all subsequent Messages) to a separate group with a new initial number.

 

Re-Order Messages

Synch

Click on the drop-down arrow and select Synchronous or Asynchronous as appropriate.

The value Synchronous disables the Kind field (below), synchronous Messages are always Calls.

 

 

Call

 

 

Asynchronous Signal Message

Kind

This field is enabled when the Synch field is set to Asynchronous.

Click on the drop-down arrow and select either Call or Signal, as appropriate.

 

Lifecycle

Select New to create a new element at the end of the Message, or Delete to terminate the message flow at the end of the Message.

If neither case applies, set the field to <none>.

 

 

Is Return

If the Message you have created is a return message, select this checkbox.

 

 

Notes

(Optional) Type any explanatory notes, formatted if you prefer.

 

 

OK

Click on this button to save the Message definition.

You can change the timing details of a message on the Timing Details dialog, and emphasize the sequence of closely-ordered messages using General Ordering
To toggle the numbering of messages on a Sequence diagram, select or deselect the Show Sequence Numbering checkbox on the Options dialog

 

 
Change the Timing Details

General Ordering

Sequence diagrams

Cancel

Click on this button to close the dialog without saving any data you have entered.

 

 

Toolbox icon

c_Message

Notes

You can also use the Message connector as an Information Flow, and realize information flows on the Message
 

Learn more