Some Comments on Process

If you are the person who plans and tracks the activities for your development project, you will want to know who does the individual theme design, who specifies the compositions, and when it should all happen. You will also want to know how complicated the composition specifications are likely to get and what can be done to minimize potential complexity.

The designs for the individual base themes are straightforward and require standard object-oriented design skills. Indeed, it is probably easier to design a single base theme than standard object-oriented projects, as the designer has to consider only a single concern. The complexity of the design is relative to the complexity of that single concern. Therefore, it is likely that a relatively junior designer could design an individual base theme. Crosscutting themes are a little more complicated and may require a designer with a little more experience. Again, however, this designer has less to worry about with a single concern.

As for when these can happenin theory, separated themes can be designed separately, since they have been selected to be independent.

However, this brings us to the question relating to the complexity of the composition specification. The more independent theme design teams are, the more likely there will be significant differences in structure and naming within the designs, and therefore the more complicated composition will be. We advise that where the design themes share a lot of concepts, the designers should meet at the start and agree on general policies, such as naming conventions and similar issues. For example, if the design problem has a notion of containers and components, then perhaps each theme that encounters these should design them with the Composite pattern. As another example, perhaps every design theme in the Crystal Game that has the notion of a player should name the corresponding class Player, and so on. You need to find a balance between, on the one hand, avoiding a situation in which everyone designs all the themes at once in this initial meeting and, on the other hand, reaping the benefits of concurrent team design where each team can design each theme separately.

So, who should specify the composition? The composer needs an overall understanding of the system and is therefore likely to be a more senior, experienced designer or software architect. This person must be able to make decisions relating to the resolution of conflicts and understand the impact of combining potentially multiple crosscutting themes with multiple base themes. With the Theme/UML approach, fewer people of this level are required than might be the case with standard object-oriented design, as it is only at the composition stage that the overall picture requires understanding. It is likely that the composer will need to examine the output of the composition process to ensure that the overall structure and behavior of the game integrate correctly and to rework theme designs or composition specifications if necessary.