View Full Version : Ext GWT vs Gwt-Ext

21 Apr 2008, 1:20 AM
Hi all,

I'm using ExtJS since the beginning and today I found some (nice) surprises: the new web site, new examples, etc. that, as usual, looks great.

Then I found also a new product: Ext GWT, that is a GWT Java wrapper that use ExtJS
to create the UI.

I have one big question: why you selected this product (Ext GWT) instead of GWT-Ext (http://gwt-ext.com/) ???

I have nothing, personally, against Ext GWT but just looking at the examples (http://www.gwt-ext.com/demo/) you will IMMEDIATELY see the difference: Gwt-Ext is much more complete than Ext GWT.

Furthermore using Gwt-Ext you will get:
- GWT wrapper for ExtJS user extenions (http://gwt-ext.com/demo-ux/)
- Supports for charts (using Yahoo Chart API, http://gwt-ext.com/demo-charts/)
- Supports for muktiple maps API (Google Map, Yahoo Map, etc. - http://www.gwt-ext.com/demo-maps/)

I would like to know if there is a special reason (or constraint) that let you decide to go for ExtGWT vs Gwt-Ext.


21 Apr 2008, 5:11 AM
Ext GWT is not a wrapper over Ext JS. Ext GWT is a Java implementation that does not use any external javascript and fully leverages the GWT API. Ext GWT does share the same look and styles as Ext JS and the API is similar in many places. In GWT-EXT, the components make calls to the underlying Ext JS code which is executing just like any other Ext JS application, where in Ext GWT, the components are written in Java. Consider events, with GWT-EXT, the events are fired and managed by the Ext javascript code, while Ext GWT uses the GWT event model. Also, consider debugging, with GWT-EXT you cannot step through all the code as it runs "under the covers" in javascript. As soon as the Java code calls javascript you lose the ability to control and trace execution. With Ext GWT, the code is in Java, so you can debug your application just like any other Java application.

There is a difference between the number of widgets int Ext GWT and GWT-EXT. This gap is decreasing as many more widgets are on the way. Also, keep in mind there are many Ext GWT features that are not in Ext JS or GWT-EXT, such as its viewer and mvc code. Ext GWT uses GWT 1.5 and takes advantage of Java 1.5 using generics, enumerations, varargs, etc.

21 Apr 2008, 9:23 AM
Ok get your point.

How we can ensure that the behavior of 'similar' widgets is consistent in the 2 systems?
Example: Window created using ExtJS code and ExtGWT code?

To me the fact that Gwt-Ext is using ExtJS are real implementation is not a major issue:

- I cannot debug JS code: of course. The same if I buy a commercial Java library without
the source code...

- If ExtJS team product a new release I can benefit automatically of bug fixing, performance
improvements and new features

- I can benefit of the great documentation of ExtJS (that to me is better than the 'simple'
JavaDoc documentation.

Of course this is just my point of view.


21 Apr 2008, 10:08 AM
I think to me, as a simple user of mygwt/gxt and gwt-ext, an important factor comes down to the ability to easily extend the gxt widgets in the gwt environments without resorting to javascript and ugliness of JSNI (sorry, I know a lot of people like JSNI - but I just find the learning curve a bit too steep and unproductive considering the mix of javascript and GWT specific notations for the integration of the two).

I also find that the size of the compiled javascript code under pure GWT using native java code be an important factor.

the debugging feature is actually also important - however I would like to treat all these libraries as bugless, full featured, and reading my programming mind things ( :-) ) I find that more often than not I need to peak here and there under the covers to understand what is going wrong with my stuff.

bottom line, I think both libraries gxt and gwt-ext are great and at this stage of RIA technology development should be considered without regard to what is duplicated where and how one widget/API is different or similar than the other. As a consumer of these technologies, the more of the alternatives the happier I will be.