Building a New Pattern

The need for a pattern can be detected in any of several ways. It may become clear that with a small amount of information (requirements) an entire component or application can be implemented with little or no invention. The coding of a collection of classes or components may become tedious. It might appear that writing a particular kind of application has become more science than art.

Each of these symptoms indicates that a pattern can be developed with the Design Pattern Toolkit (DPTK) and used to quickly generate instances of the subject application given only a few application requirements. This section describes the process by which a pattern developer can take one or more instances (exemplars) of an application that embody the alleged pattern and then define the model, view and controller components of a DPTK pattern.

It is extremely important that the pattern developer starts with an existing exemplar. Just as OO analysis and design require a set of stable and correct business requirements so to does pattern analysis and design require at least one stable and correct exemplar. There are other requirements on the exemplars we use to build a pattern, but those will be discussed later. We will assume here that a stable, correct and appropriate exemplar is being used as the basis for the development of a DPTK pattern.

This section gives a tool-independant overview of the Design Pattern Toolkit pattern authoring methodology. You can author transformations "by hand from scratch" (see "Simple Bean Pattern") or you can use the new "Exemplar Analysis" tooling to model your transformation and then generate most of the tranformation templates (see "Using Exemplar Analysis Tooling").


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