ex6_25.txt

j2ee core design patterns

Example 6.25 Validation support in Request Context Object
// Base RequestContext class provides validation scaffolding
public class RequestContext {
  public RequestContext (ServletRequest request) {
    setRequest(request);
  }

  public ValidatorResults validate() throws ValidatorException {
    try {
      InputStream inputStream =
          Thread.currentThread().getContextClassLoader().
          getResourceAsStream(getValidationResourceName());
      // Create an instance of ValidatorResources to initialize from an
      // xml file
      ValidatorResources resources = new ValidatorResources();
      ValidatorResourcesInitializer.initialize(resources, inputStream);

      // Construct validator based onloaded resources and form name
      Validator validator = new Validator(resources,
          getValidationFormName());

      // add the name bean to the validator as a resource
      // for the validations to be performed on.
      validator.addResource(Validator.BEAN_KEY, this);

      // Validation
      ValidatorResults validatorResultsAggregate = null;
      validatorResultsAggregate = validator.validate();

      // Perform generic validation error handling, if any
      return validatorResultsAggregate;
    } catch (IOException e) {
      // Handle Exception
    }
    return null;
  }

  . . .

  public void setRequest(ServletRequest request) {
    this.request = request;
  }

  private ServletRequest request;
}