Simple OnEvent mixin

This mixin is heavily based on Chenillekit OnEvent. I found that CK’s mixin had a different and too specific focus to fit my needs. I wanted to write an event mixin that does nothing but trigger an event. This is what I came up with, I believe the result is quite easy to understand, and should work as a nice foundation for other similar components and mixins.

Usage:

<input type=”button” value=”Answer yes” t:type=”any” t:id=”yesButton” t:mixins=”onEvent” t:event=”click” callback=”updateStatus”/>

Object onClickFromYesButton() {

return “Positive”; // Arguments for javascript function “updateStatus”

}

OnEvent.java

@IncludeJavaScriptLibrary("OnEvent.js")
public class OnEvent {
  @Parameter(required = true, defaultPrefix = BindingConstants.LITERAL)
  private String event;
  @Parameter
  private Object[] context;
  @Environmental
  private RenderSupport renderSupport;
  @InjectContainer
  private ClientElement container;
  @Parameter(defaultPrefix = BindingConstants.LITERAL)
  private String callback;
  @Inject
  private ComponentResources componentResources;
  void afterRender() {
    Link link = componentResources.createEventLink(event, context);
    String script = "new OnEvent('%s', '%s', '%s', '%s')";
    renderSupport.addScript(script, container.getClientId(), event, link.toRedirectURI(), callback);
  }
}

OnEvent.js

var OnEvent = Class.create({
    initialize: function(elementId, event, url, callback)
    {
        if (!$(elementId))
            throw(elementId + " doesn't exist!");
        this.element = $(elementId);
        this.callback = callback;
        this.url = url;
        this.element.observe(event, this.eventHandler.bindAsEventListener(this));
    },
    eventHandler: function(event)
    {
        new Ajax.Request(this.url, {
            method: 'get',
			onFailure: function(t)
            {
                alert('Error communication with the server: ' + t.responseText.stripTags());
            },
            onException: function(t, exception)
            {
                alert('Error communication with the server: ' + exception.message);
            },
            onSuccess: function(t)
            {
                if (this.callback)
				{
					var funcToEval = this.callback + "(" + t.responseText + ")";
					eval(funcToEval);
				}
			}.bind(this)
        });
    }
});

Update a zone on any client side event

 

Usage:

<input type=”text” t:type=”textField” value=”myValue” t:mixins=”zoneUpdater” zone=”searchResultZone” event=”performSearch” clientEvent=”onkeyup”/>

Then all you have to do is providing a listener method for the performSearch-event in your component/page class.

There is some room for improvement here in terms of more flexibility on event link context and other things. But it works.

There might be improvements in the Tapestry js library to make it easier to obtain and trigger zones. This code was developed with T 5.0.18.

 

ZoneUpdater.java

@IncludeJavaScriptLibrary("ZoneUpdater.js")
public class ZoneUpdater {
  public static final String PLACEHOLDER = "XXX";
  @Inject
  private ComponentResources resources;
  @Environmental
  private RenderSupport renderSupport;
  @Parameter(defaultPrefix = BindingConstants.LITERAL)
  private String clientEvent;
  @Parameter(defaultPrefix = BindingConstants.LITERAL, required = true)
  private String event;
  @InjectContainer
  private ClientElement element;
  @Parameter
  private Object[] context;
  @Parameter(defaultPrefix = BindingConstants.LITERAL)
  // To enable popups to fire events on this document, enter "document" here.
  private String listeningElement;
  @Parameter(defaultPrefix = BindingConstants.LITERAL, required = true)
  private String zone;
  protected Link createLink(Object[] context) {
    if (context == null) {
      context = new Object[1];
    }
    context = ArrayUtils.add(context, PLACEHOLDER); // To be replaced by javascript
    return resources.createEventLink(event, context);
  }
  void afterRender() {
    String link = createLink(context).toAbsoluteURI();
    String elementId = element.getClientId();
    if (clientEvent == null) {
      clientEvent = event;
    }
    if (listeningElement == null) {
      listeningElement = "$('" + elementId + "')";
    }
    renderSupport.addScript("new ZoneUpdater('%s', %s, '%s', '%s', '%s', '%s')", elementId, listeningElement, clientEvent, link, zone, PLACEHOLDER);
  }
}
 

ZoneUpdater.js

var ZoneUpdater = Class.create();
ZoneUpdater.prototype = {
	initialize: function(zoneElementId, listeningElement, event, link, zone, placeholder) {
		this.zoneElement = $(zoneElementId);
		this.event = event;
		this.link = link;
		this.placeholder = placeholder;		
		$T(this.zoneElement).zoneId = zone;			
		listeningElement.observe(this.event, this.updateZone.bindAsEventListener(this));
	},	
	updateZone: function(event) {
	    var zoneObject = Tapestry.findZoneManager(this.zoneElement);
	    if ( !zoneObject ) return;
	    var param;
	    if (this.zoneElement.value) {
	    	param = this.zoneElement.value;
	    }
	    if (!param) param = ' ';
	    param = this.encodeForUrl(param);
	    var updatedLink = this.link.gsub(this.placeholder, param);
	    zoneObject.updateFromURL(updatedLink);		
	},
	encodeForUrl: function(string) {
		/**
		 * See equanda.js for updated version of this
		 */
		string = string.replace(/\r\n/g,"\n");
	    var res = "";
	    for (var n = 0; n < string.length; n++)
	    {
	        var c = string.charCodeAt( n );
	        if ( '$' == string.charAt( n ) )
	        {
	            res += '$$';
	        }
	        else if ( this.inRange( c, "AZ" ) || this.inRange( c, "az" ) || this.inRange( c, "09" ) || this.inRange( c, ".." ) )
	        {
	            res += string.charAt( n )
	        }
	        else
	        {
	            var tmp = c.toString(16);
	            while ( tmp.length < 4 ) tmp = "0" + tmp;
	            res += '$' + tmp;
	        }
	    }
	    return res;
	},
	inRange: function(code, range) {
		return code >= range.charCodeAt( 0 ) &&  code <= range.charCodeAt( 1 );
	}
}