Summary

In this chapter, we explained how to specify how themes should be composed. We described a new kind of relationship called a composition relationship that is an extension to UML. We saw how, with a composition relationship, you can decide what themes should be composed; what design elements in the themes match each other and should be integrated; how themes should be integrated; how to resolve conflicts between matching elements; and how to bind base design elements to templates in crosscutting themes. Of course, a composed design will have all the scattering and tangling properties that Theme/UML is designed to avoid, but designers need only work with the individual themes, which are cleanly modularized. In the next chapter, we look at how to move forward to implementation with the theme designs.