Context

Models have a usefulness and meaning that derive from the way they are constructed, not just from the content. A modeling language must go beyond the expressive capabilities and formal rules provided by its structure and conventions. Patterns of substance are concerned with model meaning and shape about how to be correct when using the UML in a creative way. They describe how to ensure that your UML models are valid, efficiently expressive, useful, and meaningful. They should provide information in an appropriate form, not just empty graphical rhetoric or confusing symbolic bombast.

Just as speaking correctly means more than following the rules of grammar, using the UML (or any modeling language) requires a creativity that must itself be correct. However, creativity is constrained but not usually in any ways that are obvious. Patterns provide a way of explaining how to be correctly creative.

This chapter harnesses the power of modeling idioms and heuristics to provide a starting point. Patterns of substance describe the informal and practical possibilities of representing useful information with the UML. They extend the rules rationalizing the use of the UML.