[OO Design Foundation] Steps to Creating Well Designed Software - 5. Sequence Diagram

• Is about which objects are involved, and what messages are sent between them

 

Example - Note creation app button

• Uses MVC architecture, and needs the following:
  • The view instance that represents the button
  • The controller instance that intercepts an event triggered by a button, and runs it's own function
• Here,
  • 1. The view displays data and receives user input
    • 'onCreateNote' is the event that connects between 'create button' (view) and controller
  • 2. The controller
    • a. Triggers actions based on events received from its views and processes the data to be displayed
    • b. Triggers the creation of Note instance
      
      
  • 3. The user fills the note's details and presses the 'save' button
    • 'onSaveNote' is the event that connects between 'save button' (view) and controller
    • This triggers two actions "saving to local persistance", and "uploading the new note to the cloud"
      
      
      

Note

• Destruction occurance is a message occurance which represents the destruction of an instance described by the lifeline

 

References

• UML Sequence Diagrams - https://www.uml-diagrams.org/sequence-diagrams.html 
• UML and Object-Oriented Design Foundations - https://www.udemy.com/course/uml-and-object-oriented-design-foundations/