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Lost/Found Element Creation

In this section, you will describe the concept of the lost/found element and see how to create lost/found element in the Sequence diagram.
This section includes the following contents:

Concept
Create lost/found element

1. Concept

A found message is a message where the receiving event occurrence is known, but there is no (known) sending event occurrence. We interpret this to be because the origin of the message is outside the scope of the description. This may for example be noise or other activity that we do not want to describe in detail. The semantics is simply the trace (receiveEvent)
A lost message is a message where the sending event occurrence is known, but there is no receiving event occurrence. We interpret this to be because the message never reached its destination. The semantics is simply the trace (sendEvent).

2. Create lost/found element

To create a lost/found element directly in your sequence diagram, click the icon Add a Return in the toolbar and drag and drop this element inside the Sequence diagram.

Click on the Add a link Return to connect the Return with the LifeLine.

Add a name in the Label field and slect one option (e.g. Return or Throw Exception)

Here is the new Return creation which is used in the create lost/found element concept.

Please note that the Return (e.g. lost/found element) is only a graphical element and could not be saved in the UML Superstructure Model because this element doesn't exist in UML 2.2.