Composition

Composition is a specific type of Association used when a Class is a collection or container of other Classes, but the relationship is such that if the Class that functions as the container is destroyed, the Classes representing the contents are destroyed as well.

In the Business Object Modeler, Composition is represented as a filled diamond shape connected to the containing Class.

Compositions can be bi-directional, or can be navigable only in one direction. When you create a composition in Business Object Modeler, by default its navigability is from the source class to the target class.

Note: Bi-directional compositions are not supported in BPM.