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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 ion 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^{Image Removed} 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^{Image Removed} - do a search. It works in IE and FireFox.

Should webwork provide a static resource loader

• We need to provide a developer friendly way of exposing webwork static resources - primarily javascript files

• 1. User could copy them into a folder
     • This either requires a separate zip download or packaging these files within the jar
     • This is a bad idea because it is error prone when the user upgrades

• Provide a resource loading servlet that serves the resources from the webwork jar
  requires a servlet definition and mapping in web.xml
• could use a webwork.properties setting for the servlet prefix to allow user to 'mount' the static resources under a different prefix
  this makes jar upgrades easy and transparent
I have a prototype of this working in one of my apps - however it is restricted to mounting a single package on a single prefix. No support for multiple mappings. No Format

i.e.  mount com.opensymphony.webwork.static at /webwork 
request /webwork/validationAjax.js 
loads  com.opensymphony.webwork.static.validationAjax.js

• Get the validationServlet to serve the javascript code. Use '/validationServlet/client.js' as the url

• 1. Any other ideas ?

Supported Browsers

• We need to define what browsers we will support.

JavaScript API

• In webwork 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

    Code Block
    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

    Code Block
    class Errors { String[] actionErrors; Map<String, String[]> fieldErrors; // fieldName is the key }

• See this in action in webwork WW cvs head

  No Format
  /src/java/templates/xhtml/validation.vm /src/webapp/validationServlet.js /src/webapp/javascript-input.jsp

• Cloves' provided example API :

  Code Block
  function addActionErrors(messages); // should messages be an array?! function addErroraddFieldErrors(fieldName, messages); // should messages be an array?! function clearActionErrors(); function clearErrorclearFieldErrors(fieldName); function clearErrors(formName);

New

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Theme

• We need to develop a new slick looking template based on css that has full client side javascript support.
• We could mix some ideas from
  • http://www.themaninblue.com/experiment/InForm/margin.htm^{Image Removed}
  • http://www.baekdal.com/articles/Usability/usable-XMLHttpRequest/^{Image Removed}