Apache Struts 2 Documentation > Home > Overview > Whiteboard > AJAX Validation - points for discussion
Added by cameronbraid, last edited by Ted Husted on Jun 05, 2006  (view change)

Ajax Validation

Validation servlet vs Interceptor

  • Using a validation servlet requires the app developer to map any servlet filters for any action that is to be validated to the validation servlet as well.
  • Using a validation interceptor executes the validation within the context of any mapped servlet filters, as well as within the context of the action.

Custom Ajax code or Third Party Library

  • The DOJO Toolkit promises to be a very flexible and powerful toolkit, however they are only in the beginning stages. A lot of the code is coming from other dhtml toolkit projects that are very mature.
  • We only require a fairly simple xmlhttp layer a the moment. Dojo have released their dojo.io.bind package http://dojotoolkit.org/intro_to_dojo_io.html which should be sufficient for us, however I think we can produce our own XmlHTTP code for now.
  • I have implemented some custom xmlhttp / javascript code http://www.drivelater.com.au - do a search. It works in IE and FireFox.

JavaScript API

  • In WW CVS /src/webapp/validationServlet.js contains a sample ValidationServlet client javascript class. It handles the communication with the validation servlet, and exposes callbacks for handling the errors. NOTE : I think we can re-work this a bit. I currently have lots of onWhatever callbacks. I think we should just have onErrors, and let the template designer do what they want with the Errors object.
    • Sample Usage
      var validation = new ValidationServlet('/validationServlet/client.js');
      validation.onErrors = function(inputObject, errors) {
      	// clear old errors
      	// display new errors
      }
    • The errors param for the onErrors callback is a javascript object that has this structure
      class Errors {
      	String[] actionErrors;
      	Map<String, String[]> fieldErrors; // fieldName is the key
      }
  • See this in action in WW cvs head
     
    /src/java/templates/xhtml/validation.vm
    /src/webapp/validationServlet.js
    /src/webapp/javascript-input.jsp
    
  • Cloves' provided example API :
    function addActionErrors(messages); // should messages be an array?!
    function addFieldErrors(fieldName, messages); // should messages be an array?!
    function clearActionErrors();
    function clearFieldErrors(fieldName);
    function clearErrors(formName);

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