Fundamentals of UML Diagrams

A diagram is the graphical presentation of a set of elements. UML has a lot of different diagrams. Read this section, and make sure you can differentiate between different diagrams.

3. Using the <> relationship

3.3. Collaboration Diagram

A collaboration diagram is an interaction diagram that emphasizes the structural organization of the objects that send and receive messages. Collaboration diagrams express both the context of a group of objects and the interaction between these objects. It focuses upon the relationships between the objects. They are very useful for visualizing the way several objects collaborate to get a job done and for comparing a dynamic model with a static model. When creating collaboration diagrams, patterns are used to justify relationships. Patterns are best principles for assigning responsibilities to objects. Figure 2.10 shows an example of a collaboration diagram.

Figure 2.10: Example of a Collaboration Diagram

Note for Sequence and Collaboration Diagrams

  • Interaction diagrams require use cases, system operation contracts, and domain (class or conceptual) model to already exist
  • Sequence diagrams and collaboration diagrams are isomorphic, meaning that you can take one and transform it into the other. 
  • Collaboration and sequence diagrams describe the same information, and can be transformed into one another without difficulty. 
  • The choice between the two depends upon what the designer wants to make visually apparent.