UML Diagrams

This is a Use Case diagram

The use case diagram captures an external view of the system being modelled and thus helps to reveal the system boundaries and serves as a basis for range estimates

It consists of 3 parts:

Actor - User System Boundary - the boundaries of the system, the program itself. UseCase - the usage scenario line with an open arrow - include (pay attention to directions) - right to left (mandatory to include in the scenario), right to left - extend (optionally extends)

the diagram always needs a document that verbally describes the project

It is a sequence of related transactions between a participant (usually a user in a specific role, but also another system) and the system during a mutual dialogue

The main purpose is to capture the actors who interact with the system and the relationships between the services and those to whom they are provided, in both visual and textual form

This is a sequence diagram A sequence diagram shows us how objects in the application or classes in the code interact with each other captures the temporally ordered sequence of messages sent between objects most often shows the interaction of several sample objects within a single use case

It consists of two types of objects: Actor - Stickman symbol Object - Rectangle. Objects are placed in sequential order from right to left The individual processes or objects involved in the described use case are placed at the top of the diagram Lines (lifelines) run downwards from them to show the passage of time Between the lines, horizontal arrows of different types are drawn to represent messages sent between objects, solid arrows indicate a call, dashed arrows indicate a response, and oblong rectangles on the vertical lines indicate the time it took to process a given message or wait for a response Don't forget the alternative messages (rectangle where the situation is 2 scenarios)

This is a state diagram. A state diagram is a way of graphically writing the evolution of a system that has a finite number of states

Such a system can be a finite automaton (state automaton) or other similar systems that express the states of a certain object and the transitions (transition function) between them.

The diagram provides a set of elements to describe the behaviour of a system that is expressed by a transition of states and is controlled by an external input.

This is a class diagram