title: Validation in GWT+GAE-based application
body: <p>Is there any standard approach to input data validation and error displaying in GWT+GAE-based application?</p>
  
  <p>Eclipse plugin generates GWT project with shared.FieldVerifier class, which provides static method for values validation:</p>
  
  <pre><code>public static boolean isValidName(String name) {
      if (name == null) {
          return false;
      }
      return name.length() &gt; 3;
  }
  </code></pre>
  
  <p>isValidName() method is then called on input data in client-side code and server-side code, and if something is wrong, error logics is executed. BTW, I suppose, this approach (set of static validation methods, specific error displaying logics in each case) may be not very scalable.</p>
  
  <p>Also, I found <a href="http://code.google.com/p/gwt-validation/" rel="nofollow">gwt-validation project on code.google.com</a>, but I did not investigate it yet.</p>
  
  <p>Could you please recommend any standard approaches / libraries, which can help to handle validation and error displaying? Is gwt-validation library a standard?</p>