Programming Jakarta Struts, Second Edition

Using the DynaActionForm Class

Using the ActionForm class has many advantages over performing the functionality yourself in the Action class or some set of helper utility classes. Because the behavior the ActionForm class provides is needed in nearly every web application and often many times in the same application, using the framework to perform the work can really reduce the development time and your frustration level. However, there are a few very important downsides to using ActionForms.

The biggest problem with using ActionForms is the sheer number of classes that it can add to a project. Even if you share ActionForm definitions across many pages, the additional classes make it more difficult to manage and maintain a project. This is why some developers create a single ActionForm and implement the properties for all of the HTML forms within it. The problem with this approach, of course, is that combining the fields into one class makes it a point of contention on a project that has more than just a few developers.

Another major liability is the requirement to define the properties in the ActionForm that need to be captured from the HTML form. If a property is added or removed from the HTML form, the ActionForm class may need to be modified and recompiled.

For these reasons, a new type of ActionForm, which is dynamic in nature and allows you to avoid having to create concrete ActionForm classes for your application, was added to the framework. The dynamic ActionForm is implemented ...