Check all mixin

This is a VERY simple mixin that turns a regular checkbox into a controller checkbox. It's a nice example of how easy it is to create these elegant little mixins and components in Tapestry 5!

Example: <input type="checkkbox" t:type="any" t:mixins="checkall" t:controlledClass="element-selected"/>

CheckAll.java

/**
 * Mixin for checkboxes that should control the checked state of a group of other checkboxes. All the controlled checkboxes need to
 * have the CSS class specified in the controlledClass parameter. 
 * 
 * @author Inge
 *
 */
public class CheckAll {

  /**
   * The controller checkbox that this mixin applies to.
   */
  @InjectContainer
  private ClientElement container;

  @Environmental
  private RenderSupport renderSupport;

  /**
   * The CSS class that all controlled checkboxes must have to be controlled by the master checkbox.
   */
  @Parameter(required = true, defaultPrefix = BindingConstants.LITERAL)
  private String controlledClass;

  void afterRender() {
    renderSupport.addScript("new CheckAll('%s', '%s')", container.getClientId(), controlledClass);
  }
}

CheckAll.js

var CheckAll = Class.create( {
 initialize : function(controllerId, controlledClass) {
  this.controller = $(controllerId);
  this.controlledClass = controlledClass;
  this.controller.observe('change', this.toggle.bindAsEventListener(this));
 },
 toggle: function() {
  var checked = this.controller.checked;
  var controlledCheckboxes = $$('input.' + this.controlledClass);
  controlledCheckboxes.each(function(checkbox) {
   checkbox.checked = checked;
  });
 }
});

New and better (?) ZoneUpdater

I recently sat down and did some evaluation of the ZoneUpdater code. I found that it is a bit hard to configure and debug, so I decided to do a little refactoring to trade some flexibility for readability and usability.

I also wanted to add a missing feature, the ability to update a zone simply by calling a javascript function. This is a nice way of "object orienting" different features/sections on a page, by giving different sections their own client API that they can communicate with.

Most important changes:
- Removed support for specifying another listening element than the container
- Cleaner code
- Request parameter instead of encoding parameter into link context.
- Generates a javascript variable to easy zone update through javascript.

I also wanted to add an internal listener that triggers the actual event with context, so the page/component listener doesn't have to inject the Request and do request.getParameter("param"). Didn't succeed so far.

Anyway, here's the modified code. No code formatting this time, but it should be short enough to be readable. Enjoy :)

ZoneUpdater.java

@IncludeJavaScriptLibrary( { "ZoneUpdater.js" })
public class ZoneUpdater {

  @Inject
  private ComponentResources resources;

  @Environmental
  private RenderSupport renderSupport;

  /**
   * The event to listen for on the client. If not specified, zone update can only be triggered manually through calling updateZone on the JS object.
   */
  @Parameter(defaultPrefix = BindingConstants.LITERAL)
  private String clientEvent;

  /**
   * The event to listen for in your component class
   */
  @Parameter(defaultPrefix = BindingConstants.LITERAL, required = true)
  private String event;

  @Parameter(defaultPrefix = BindingConstants.LITERAL, value = "default")
  private String prefix;

  /**
   * The element we attach ourselves to
   */
  @InjectContainer
  private ClientElement element;

  @Parameter
  private Object[] context;

  /**
   * The zone to be updated by us.
   */
  @Parameter(defaultPrefix = BindingConstants.LITERAL, required = true)
  private String zone;

  void afterRender() {
    String url = resources.createEventLink(event, context).toAbsoluteURI();
    String elementId = element.getClientId();
    JSONObject spec = new JSONObject();
    spec.put("url", url);
    spec.put("elementId", elementId);
    spec.put("event", clientEvent);
    spec.put("zone", zone);

    renderSupport.addScript("%sZoneUpdater = new ZoneUpdater(%s)", prefix, spec.toString());
  }
}

ZoneUpdater.js

var ZoneUpdater = Class.create({
 initialize: function(spec) {
  this.element = $(spec.elementId);  
  this.url = spec.url;
  $T(this.element).zoneId = spec.zone;   
  if (spec.event) {
   this.event = spec.event;
   this.element.observe(this.event, this.updateZone.bindAsEventListener(this));
  }
 }, 
 updateZone: function() {
     var zoneManager = Tapestry.findZoneManager(this.element);
     if ( !zoneManager ) return;
     
     var updatedUrl = this.url;
     if (this.element.value) {
      var param = this.element.value;
      if (param) {
       updatedUrl = addParameter('param', param, updatedUrl); // You need to provide your own function for this...
      }
     }          
     zoneManager.updateFromURL(updatedUrl);  
 }
});