Programming Jakarta Struts, Second Edition

Using an ActionForm with the Validator

You can’t use the standard Struts ActionForm class with the Validator. Instead, you need to use a subclass of the ActionForm class that is specifically designed to work with the Validator framework. There are two root subclasses to select from, depending on whether you are planning to use dynamic ActionForms. Figure 11-1 shows the ActionForm and its descendants, to help you visualize the hierarchy.

Figure 11-1. The ActionForm class hierarchy

If you are using dynamic ActionForms, you should use the DynaValidatorForm branch of the hierarchy. If you are using standard ActionForms, you can use the ValidatorForm or one of its descendants instead.

Tip

Whether you use dynamic or regular ActionForms, the manner in which you configure the Validator is the same. Just be sure that whichever ActionForm subclass you choose, you configure the form-bean section of the Struts configuration file using the fully qualified class name. See “The form-beans element” in Chapter 4 for more details.

Dynamic or standard is only the first decision that you have to make when choosing the proper ActionForm subclass. Notice that in both the dynamic and standard branch of the ActionForm hierarchy in Figure 11-1, there are two versions of ValidatorForm. The parent class is called ValidatorForm, or DynaValidatorForm for the dynamic branch.

Each of these has a subclass that ...