UML - RJAE5/2143-OOP GitHub Wiki

Universal Modeling Language (UML)

The industry standardized visual language used for modeling and designing software systems is known as UML. It provides a set of diagram types to represent different aspects of a system, including its structure, behavior, and interactions. UML helps developers, analysts, and more communicate system designs clearly and effectively throughout the development lifecycle.

Structural Diagrams

Structural diagrams mainly focus on how a system is at any one point during the runtime of a program, representing its components and how they interact with one another.

Class Diagram
- Represents the system's classes, attributes, methods, and other relationships.
Object Diagram
- Shows instances of objects and their relationships at a particular point in time.
Component Diagram
- Illustrates the physical components of a system and their interactions.
Deployment Diagram
- Displays the hardware architecture and how software components are deployed on it.
Package Diagram
- Organizes the system into packages to show dependencies between groups of classes.

Class Diagram Example

The following image illustrates a Team class which is related to a Player class.

Behavioral Diagram

Behavioral diagrams often describe the dynamic interactions of a system, including processes, and state changes over time.

Use Case Diagram
- Depicts the functional requirements of the system from an end-user perspective.
Sequence Diagram
- Shows the sequence of messages exchanged between objects to carry out a particular functionality.
Activity Diagram
- Models the flow of control and data within a system or process, often used for workflows.
State Diagram
- Represents the states of an object and the transitions between them in response to events.
Communication Diagram
- Similar to sequence diagrams but focuses on the objects involved and their interactions.

Sequence Diagram Example

The following image depicts a sequence diagram of the process of retrieving a balance within a certain bank account given an inheritance chain.

Interaction Diagrams

Interaction diagrams emphasize the communication and interaction between components or objects.

Interaction Overview Diagram
- Combines activity and sequence diagrams to show the flow of control and interactions.
Timing Diagram
- Focuses on the timing constraints of the interactions between components over a period of time.

Interaction Overview Diagram Example

The following interaction overview diagram shows the process of reserving a hotel room and all potential outcomes/loops.

Implementation Diagrams

Implementation diagrams focus on the details of how system components will be implemented and deployed

Component Diagram
- Shows the organization of software components and their dependencies.
Deployment Diagram
- Represents the system's physical deployment on hardware and the relationships between the components.

Deployment Diagram Example

The following deployment diagram represents the overall deployment of a Book Club Web App.

Important Notes

UML provides a standardized way of communicating expectations and outcomes for software.
There is a large variety of UML diagrams for almost every particular need.
In OOP, UML can help visualize the complex interactions that occur between objects.