Tutorials : Applying Design Patterns to Your Struts Validation Framework:

Applying Design Patterns to Your Struts Validation Framework

by James (Jun B.) You

In today's Web applications, friendly user input validations with obvious graphic alert images and warning messages have become standard. These input validation rules are defined based on business needs, which filter out any bad data input by users. This not only increases system stability, but also improves user experience. How can you add this type of validation to your Web application?

The popular Java Web MVC framework, Apache Struts, provides an ideal solution for validating form input. This article will show you how to use it through solving a practical validation scenario. You'll see two different implementation solutions: the first uses the traditional procedural programming method; the second demonstrates the object-oriented approach by way of Struts customized validation plug-in integration.

Hopefully, this comparison will show you how object-oriented design principles and design patterns-specifically, the strategy, factory, and singleton patterns, can be applied to Struts' customized form validation.

The Various Validation Scenarios

Suppose you have a company named ABC Wireless Inc., which provides its customers with a wireless service. When the customers enroll in their service, they provide a personal identity or credential. This private, sensitive data is securely stored in an Oracle database server through Oracle's efficient data encryption API.

The self-registration form provided by ABC Wireless Inc. needs to validate customers based on their personal identity numbers, which were created when the customer first registered. The personal identity or credential could be one of the following:

  • ABC PIN (Personal Identity Number)
  • Social Assistance No.
  • Driver License
  • Treaty Status No.
  • Immigration No.
  • Veteran ID
  • Health Card No.
  • Old Age Security No.
  • Birth Certificate No.
  • Passport No.

 

  • Refugee Claimant No.

  .... more and more (might be Credit Card Number)

Each personal identity has its own validation rules: minimum length, maximum length, and data format pattern. Nowadays, you can changed (removed/added/modified) these dynamically. Listing 1 shows detailed validation rules.

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