What is activation in sequence diagram?

Used in a sequence diagram, an activation shows the time period during which an object or actor is performing an action. On an object lifeline, the activation rectangle sits on top of the lifeline. Align the top of the rectangle with the initiation time and the bottom with the completion time.

What are the three key parts of UML sequence diagrams?

Interaction Fragment

  • occurrence.
  • execution.
  • state invariant.
  • combined fragment.
  • interaction use.

What is lifeline in UML sequence diagram?

In UML diagrams, such as sequence or communication diagrams, lifelines represent the objects that participate in an interaction. For example, in a banking scenario, lifelines can represent objects such as a bank system or customer. Each instance in an interaction is represented by a lifeline.

What are the key components in a sequence diagram?

Basic Sequence Diagram Notations

  • Class Roles or Participants. Class roles describe the way an object will behave in context.
  • Activation or Execution Occurrence.
  • Messages.
  • Lifelines.
  • Synchronous Message.
  • Asynchronous Message.
  • Reply or Return Message.
  • Self Message.

What are the elements used in sequence diagram?

A sequence diagram shows, as parallel vertical lines (lifelines), different processes or objects that live simultaneously, and, as horizontal arrows, the messages exchanged between them, in the order in which they occur. This allows the specification of simple runtime scenarios in a graphical manner.

What are the three different types of message arrows?

Explanation: Three different types of message arrows are- Synchronous, Asynchronous, Synchronous with instance creation.

How do you use Alt fragments in sequence diagrams?

Select Alt. Press on the blank area of the diagram and drag to cover the Person and ATM Machine lifeline. Draw a message from ATM Machine lifeline to Person lifeline in the upper compartment of the alternative combined fragment. Name it as Ask for password.

What is activation in UML sequence diagram?

Activation – UML Sequence Diagram Element Activation Activation elements in the UML Sequence Diagram are boxes on the lifelines. These are also called the method-invocation boxes, and indicate that an object is responding to a message. It starts when the message is received and ends when the object is done handling the message.

What are the major elements of UML sequence diagram?

Major elements of UML sequence diagram. Lifeline is a named element which represents an individual participant in the interaction. While parts and structural features may have multiplicity greater than 1, lifelines represent only one interacting entity.

How to simplify the sequence diagram?

Large and complex sequence diagrams could be simplified with interaction uses. It is also common reusing some interaction between several other interactions. The interaction use is shown as a combined fragmentwith operator ref. Use Login interaction to authenticate user and assign result back to the user attribute of Site Controller.

What are messages in the sequence diagram?

The messages depict the interaction between the objects and are represented by arrows. They are in the sequential order on the lifeline. The core of the sequence diagram is formed by messages and lifelines. Following are types of messages enlisted below: