Component Diagrams

Owned by Computer Science Department
Last updated: Jul 18, 2023
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A component diagram in UML (Unified Modeling Language) is a type of static structure diagram that shows how a software system is split up into components and how these components interact with each other. It provides a high-level view of the structure and organization of the software components.

Components can be anything that is part of a system and resides within it. This can include software components like databases, user interfaces, middleware systems, business logic, and more.

Here's a breakdown of the main components in a UML component diagram:

  1. Component: A component represents a modular part of a system. It encapsulates its contents and whose manifestation is replaceable within its environment. In UML diagrams, components are depicted as rectangles with two smaller rectangles on the left side.

  2. Interface: An interface is a specification of behavior. Other components in the system can interact with a component through its interfaces. Interfaces in UML component diagrams are depicted by a circle (also known as a "lollipop" symbol) or a half-circle attached to the component.

  3. Dependency: A dependency relationship between two components means that if one component changes, the other component may also need to be changed. Dependency is represented by a dashed arrow.

  4. Assembly Connector: An assembly connector is a type of connector that links a component's provided interface to another component's required interface. It's typically represented by a line with a filled circle at one end and an open arrowhead at the other.

  5. Delegation Connector: Delegation connectors show that a component is using an internal component to provide or require an interface. It's represented as a line with an open arrowhead.

  6. Package: Packages are used to group related elements such as components. A package is represented as a large rectangle with a small tab attached to the top.

Component diagrams help to visualize the high-level organization and structure of the software system. It's a great tool to use when you want to understand the high-level architecture of a software system.