UML Component Diagrams Reference

The major elements of UML component diagram - component, provided interface, required interface, port, connectors.

Notation	Description
Component
WeatherServices component	Component is notated by a classifier symbol with «component» keyword. This notation was introduced in UML 2.0.

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UserServices component | Optionally, a component icon that is similar to the UML 1.4 icon can be used in the upper right corner of the component rectangle. If the icon symbol is shown, the keyword «component» may be omitted.

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External view of User Services component - it provides IUserServices interface and requires IOrderServices interface. | External view or black box component notation - showing a listing of the properties of a component - the interfaces and/or individual operations and attributes listed in the compartments of a component box.

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CustomerEJB Component in UML 1.x notation | For backward compatibility reasons, the UML 1.x notation with protruding rectangles may still be used in UML 2.5.

| | Provided Interface | | |
Weather Services component provides (implements) Weather Forecast interface. | A provided interface is the one that is either
- realized directly by the component itself, or
- realized by one of the classifiers realizing component, or
- is provided by a public port of the component.

| | Required Interface | | |
User Services component requires IOrderServices interface. | A required interface is either
- designated by usage dependency from the component itself, or
- designated by usage dependency from one of the classifiers realizing component, or
- is required by a public port of the component.

| | Component Realization | | |
Component UserService realized by UserServlet and UserDAO. | A component realization is notated in the same way as the realization dependency i.e., as a general dashed line from implementing classifiers to realized component having hollow triangle as an arrowhead.

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White box view of User Services component - it is realized by UserServlet and UserDAO and manifested by UserService.jar artifact. | Internal classifiers that realize the behavior of a component may be listed in the additional «realizations» compartment - internal, or white box view of a Component. Compartments may also be used to display a listing of any parts and connectors, or any implementing artifacts.

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Component UserService realized by UserServlet and UserDAO. | Internal classifiers that realize the behavior of a component may be displayed nested within the component shape.

| | Delegation Connector | | |
Delegation connector from the delegating port to the UserServlet part. | A delegation connector is a connector that links the external contract of a component (as specified by its ports) to the realization of that behavior. It represents the forwarding of events (operation requests and events): a signal that arrives at a port that has a delegation connector to one or more parts or ports on parts will be passed on to those targets for handling.
A delegation connector is notated as a connector from the delegating port to the handling port or part. | |
Delegation connector from the delegating port to the simple port of SearchEngine. | If the delegation is handled by a simple port, then the delegation connector may optionally be shown connected to the single lollipop of the realizing component. | |
Delegation connector from the simple port of Authentication component to the delegating port. | If the delegation is handled by a simple port, then the delegation connector may optionally be shown connected to the single socket of the component that requires the interface. | | Assembly Connector | | |
Assembly connector between ports of Authentication and Customers components. | An assembly connector is a connector between two or more parts or ports on parts that defines that one or more parts provide the services that other parts use.
Assembly connector is notated as a connector between two or more parts or ports on parts. | |
Assembly connector between simple ports of Authentication and Customers components. | When an assembly connector connects simple ports (ports that provide or require a single interface), it may be notated by a “ball-and-socket” connection between a provided interface and a required interface. | |
Assembly connector that assembles three parts. | Where multiple components have simple ports that provide or require the same interface, a single symbol representing the interface can be shown, and lines from the components can be drawn to that symbol. This presentation option is applicable whether the interface is shown using “ball-and-socket” notation, or just using a required or provided interface symbol. |

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