Link with confirmation

 

This is  a component that adds confirmation to a regular EventLink. It does this by using the TapestryExt.js library introduced in my previous post to trigger a link after intercepting and cancelling it first. It works both with and without zones.

It is used excactly like an EventLink, with an additional “message” parameter, to display in confirmation box.

For now, I only implemented a standard javascript confirm box. But it shouldn’t be too hard extending this with more fancy interaction with DHTML.

I’m not completely comfortable with the techniques used here. Some of it looks a lot like a hack in my opinion, especially the part about intercepting/cancelling a zone listener and re-adding it afterwards using copy-paste from tapestry.js.

ConfirmLink.java:

/**
 * Displays a javascript confirmation box before actually triggering the link.
 * 
 * @author Inge
 *
 */
@IncludeJavaScriptLibrary({"TapestryExt.js, "ConfirmLink.js"})
public class ConfirmLink implements ClientElement {    
  @Environmental
  private RenderSupport renderSupport;  
  
  @Parameter("literal:Do you really want to delete?")
  private String message;
  @Component(publishParameters="event,zone,context", inheritInformalParameters=true)
  private EventLink confirmLink;
  
  void afterRender() {
    String url = confirmLink.getLink().toRedirectURI();
    renderSupport.addScript("new ConfirmLink('%s', '%s', '%s')", confirmLink.getClientId(), url, message);
  }
  
  public String getClientId() {
    return confirmLink.getClientId();
  }
}
 

ConfirmLink.js

var ConfirmLink = Class.create({
  initialize: function(element, url, message) {
    this.element = $(element);
    this.url = url;
    this.message = message;
    this.initListeners = this.initListeners.bind(this);
    this.initListeners.defer();
    // Makes it run after Tapestry:init to be able to delete
    // zone listener added by Tapestry and start listening for
    // our modded version instead.    
  },
  onclick: function(event) {
    Event.stop(event);
    if (confirm(this.message)) {
      TapestryExt.triggerLink(this.element, this.url);
    }
  },
  initListeners: function() {
    this.element.stopObserving('click'); // Remove zone update, will be re-added later by TapestryExt.js.
    this.element.observe('click', this.onclick.bindAsEventListener(this));
  }
});

Missing javascript

I think there are some important things missing from Tapestry.js to release the full potential of Tapetsry 5 and AJAX. I have started working on a javascript class, TapestryExt, that extends the functionality of Tapestry.js.

My wish is to see all of this and more built in to tapestry.

 

/**
 * Commonly needed functions that are absent in the default Tapestry js lib.
 */
var TapestryExt = {
  /**
   * If the specified form listens for the Tapestry.FORM_PROCESS_SUBMIT_EVENT event
   * (all forms with a zone specified do), it will AJAX-submit and update its zone after.
   */
  submitZoneForm : function(element) {    
    element = $(element)
    if (!element) {
      Tapestry.error('Could not find form to trigger AJAX submit on');
      return;
    }
    element.fire(Tapestry.FORM_PROCESS_SUBMIT_EVENT);
  },
  /**
   * Trigger any link, zone or not. 
   * 
   * If no url is provided, the href attribute of element will be used.
   */
  triggerLink : function(element, url) {
    element = $(element);
    if (!url) {
      url = element.href;
    }    
    if (!url) {
      Tapestry.error('Unable to find url to trigger on element ' + element.id);
    }
    var zoneObject = Tapestry.findZoneManager(element);
    if (zoneObject) {    
      zoneObject.updateFromURL(url);
    }
    else {
      // Regular link
      // Note: this will skip all event observers on this link!
      window.location.href = url;
    }
  }  
}

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 );
	}
}

Open a page in a popup window

This mixin can be applied to any element that has an onclick event. It opens the specified page in a new window. There is room for more parameters here for styling the window, and possibly for using other events than onclick as a trigger.

Usage:

<input type=”button” value=”View shopping cart” t:mixins=”popupPageLink” page=”cart/view” context=”cartId”/>

Java:

import org.apache.tapestry5.BindingConstants;
import org.apache.tapestry5.ClientElement;
import org.apache.tapestry5.ComponentResources;
import org.apache.tapestry5.Link;
import org.apache.tapestry5.RenderSupport;
import org.apache.tapestry5.annotations.Environmental;
import org.apache.tapestry5.annotations.IncludeJavaScriptLibrary;
import org.apache.tapestry5.annotations.InjectContainer;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.ioc.annotations.Inject;
@IncludeJavaScriptLibrary("PopupPageLink.js")
public class PopupPageLink {
  @Inject
  private ComponentResources resources;
  @Environmental
  private RenderSupport renderSupport;
  @InjectContainer
  private ClientElement container;
  @Parameter(required = true, defaultPrefix = BindingConstants.LITERAL)
  private String page;
  
  @Parameter(defaultPrefix = BindingConstants.LITERAL, value="800")
  private String width;
  
  @Parameter(defaultPrefix = BindingConstants.LITERAL, value="600")
  private String height;
  @Parameter
  private Object[] context;
  void afterRender() {
    Link link = resources.createPageLink(page, true, context);
    renderSupport.addScript("new PopupPageLink('%s', '%s', %s, %s);", container.getClientId(), link, width, height);
  }
}

Javascript:

var PopupPageLink = Class.create();
PopupPageLink.prototype = {
	initialize: function(id, link, width, height) {
		this.element = $(id);
		this.link = link;
		this.width = width;
		this.height = height;
		Event.observe(this.element, 'click', this.onclick.bindAsEventListener(this));
	},
	onclick: function() {
		var	name = 'dialogWindow';
		var win = window.open(this.link,name,'width=' + this.width + ',height=' + this.height + ',resizable=yes,scrollbars=yes,menubar=no,screenX=0,screenY=0,left=0,top=0' );
	    win.focus();
	}
}

Enforce max length on textareas and textfields

This is a mixin that can be used to enforce the maximum content length of any textarea or text input. It uses javascript to chop off any character that exceeds the given maxlength.

Usage:

<textarea t:type="textarea" t:mixins="maxlength" max="100"></textarea>

MaxLength.java

/**
 * Enforces maxlength on a textfield or a textarea
 * 
 * @author Inge
 *
 */
@IncludeJavaScriptLibrary("MaxLength.js")
public class MaxLength {
  
  @InjectContainer
  private ClientElement container;
  
  @Parameter(required=true)
  private int max;
  
  @Parameter("true")
  private boolean displayCounter;
  
  @Environmental
  private RenderSupport renderSupport;
  
  void afterRender(MarkupWriter writer) {
    String id = container.getClientId();
    String counterId = id + "-counter";
    writer.element("div", "id", counterId + "-container");
    if (!displayCounter) {
      writer.attributes("style", "display: none");
    }
    writer.element("input", "type", "text", "id", counterId, "disabled", "disabled", "size", "3");    
    writer.end();
    writer.end();
    renderSupport.addScript("new MaxLength('%s', '%s', %s)", id, counterId, max);
  }
}

 MaxLenght.js

var MaxLength = Class.create();
MaxLength.prototype = {
	initialize: function(id, counterId, max) {
		this.max = max;
		this.element = $(id);
		this.element.observe('keyup', this.keyup.bindAsEventListener(this));
		this.counterElement = $(counterId);
		this.updateCounter();		
	},
	keyup: function(event) {
		if (this.element.value.length > this.max) {
			this.element.value = this.element.value.substring(0, this.max);
		}
		this.updateCounter();
	},
	updateCounter: function() {
		var currentLength = this.element.value.length;
		this.counterElement.value = (this.max - currentLength);
	}
}