Composite Structure Diagram

A Composite Structure diagram reflects the internal collaboration of Classes, Interfaces or Components (and their Properties) to describe a functionality. Composite Structure diagrams are similar to Class diagrams, except that they model a specific usage of the structure. Class diagrams model a static view of Class structures, including their attributes and behaviors. A Composite Structure diagram is used to express run-time architectures, usage patterns and the participating elements' relationships, which might not be reflected by static diagrams.

In a Composite Structure diagram, Classes are accessed as Parts or run-time instances fulfilling a particular role. These Parts can have multiplicity, if the role filled by the Class requires multiple instances. Ports defined by a Part's Class should be represented in the composite structure, maintaining that all connecting Parts provide the required interfaces specified by the Port. There is extensive flexibility, and an ensuing complexity, that come with modeling composite structures. To optimize your modeling, consider building Collaborations to represent reusable patterns responding to your design issues.

Example Diagram

The following diagram shows a Collaboration used in Composite Structure diagrams to model common patterns. This particular example shows a relationship for performing an installation.

The following diagram uses the Install Collaboration in a Collaboration Occurrence, and applies it to the UtilLoad Class via a «represents» relationship. This indicates that the classifier UtilLoad uses the collaboration pattern within its implementation.

For further examples of Composite Structure diagrams, see the Toolbox elements listed below.

Toolbox Elements and Connectors

Select Composite Structure diagram elements and connectors from the Composite pages of the Toolbox.

Enterprise Architect also supports a stereotyped Collaboration to represent a Business Use Case Realization in business modeling.

OMG UML Specification

The OMG UML specification (UML Superstructure Specification, v2.1.1, p. 193) states:

A composite structure diagram depicts the internal structure of a classifier, as well as the use of a collaboration in a collaboration use.