Explanation

Component diagrams show the structure of components, including classifiers that specify components, and artifacts that implement them.

They can also be used to show the high level structure of the Implementation Model in terms of Implementation Subsystems, and relationships between Implementation Elements.

Use

The most important use of the component diagram in RUP is to show the high level structure of the Implementation Model. Specifically:

• Implementation Subsystems and their import dependencies. See Guideline: Import Dependency in Implementation.
• The Implementation Subsystems organized in layers.

A secondary use of the component diagram is to show:

• Source code files and their compilation dependencies. See Guideline: Compilation Dependency in Implementation.
• Application files and their run-time dependencies.
• Derivation relationships between source code files and the files that result from compiling or linking.
• Implement dependencies between implementation elements and the design elements that they implement. See Guideline: Manifest Dependency.

Note that the RUP emphasizes the use of the Component Diagram for modeling Implementation Subsystems, significant Implementation Elements, and their relationships. However, a component diagram that shows UML components and the classifiers that specify those components, can also be used in the Design Model, using the UML component to represent Artifact: Design Subsystem. See Guideline: Design Subsystem for more on this topic.