Unified Modelling Language

Unified Modeling Language (UML) is a modelling language for software engineering.

UML has been adopted as a standard by the Object Management Group (OMG) and International Standard Organization (ISO).

Object Contraint Language (OCL) defines the rules for model elements.

In its latest version as of 2023, UML 2.5 consist of two elements:

UML Specification 2.5
OCL 2.4

List of UML Diagram Types

Non-exhaustive list of UML diagram types:

Structural
- Class
- Component
- Composite structure
- Deployment
- Object
- Package
- Profile
Behavioral
- General
  - Activity
  - Use case
- Interaction
  - Sequence
  - Communication
  - Interaction overview
  - Timing

Structural

Class Diagram

You can read this post about class diagrams.

Component Diagram

Component diagram are recognized easily by the connectors.

Package Diagram

A package diagram is at a higher level of a class diagram, and focuses on how software components are structured within each package and how they interact together.

Behavioral

General behavioral Diagrams

I define general behavioral diagrams that does not belong to any specific subset of behavioral diagrams

Use Case Diagram

Use Case diagram is a graphical depiction of a user’s possible interactions with a system.

It is usually done at the earliest stages of design.

Activity Diagram

An activity diagram represents a workflow.

A condition nodes is represented by a diamond with a text that represent the condition.

It represents the actions. It does not represent the actor or agent performing the action.

A merge node is a control node that brings together multiple incoming alternate flows to accept single outgoing flow. There is no joining of tokens. It is represented by a diamond. Merge should not be used to synchronize concurrent flows.

A join node is a control node that has multiple incoming edges and one outgoing edge and is used to synchronize incoming concurrent flows. It is represented by a black filled rectangle. Join nodes are introduced to support parallelism in activities.

A swimlane diagram would be an activity diagram where the processes and decisions can be grouped in lanes.

Interaction Diagrams

Interaction diagrams are a subset of behavioral diagrams.

Sequence diagram

A sequence diagram displays the actors and the actions taken by them.

They are easily recognized because its actor maintains a vertical line.

Communication diagrams

A communication diagram combines information present in Class, Sequence, and Use Case diagrams.

External references

Wikipedia community; “Unified Modelling Language“; Wikipedia