Tag Archives: gwt

Welcome to TheServerSide Java Symposium 2011!

Posted on by
1
I'm Speaking at TheServerSide Java Symposium Jeanne and I are both be presenting talks at TheServerSide Java Symposium this week in sunny Las Vegas! Come join us and feel free to say hello.

I’m giving a lecture Wednesday morning entitled “GWT Roundup: An Overview of Google’s Web Toolkit and Hybrid Integration” which provides a review of GWT for old and new GWT developers alike. I will also be speaking as part of a panel hosted by Cameron McKenzie on Friday afternoon called “Client Side Development Smackdown” .

Jeanne’s giving a talk on Friday afternoon called “Throw Away All The Rules. Now What Process Do You Follow?” and is about what processes are important if you aren’t being forced to follow any. It uses the CodeRanch forum conversion project as an example.

GWT 2.2 Breaks Most Plug-ins

Posted on by
3
Google Web Toolkit I often comment that the GWT API is extremely unstable, more so than most other open source projects, due to the vast number of changes in each release. When Google released GWT 2.2 a few weeks ago, the release notes implied this was a relatively minor release. After attempted to update a fairly large GWT project to 2.2, I discovered a major issue: all of the referenced GWT plugins broke and required a new version that was GWT 2.2-compatible.

The API Change – Small and Subtle

In GWT 2.2, Google changed the class library JClassType from an abstract class to an interface. On the surface, this may seem like a minor change that would not affect most developers. Java compiler experts may be aware, though, that changing the class type alters the byte code of classes that compile against this class. In other words, any JAR or library compiled prior to GWT 2.2 that references this class will be unable to be used in GWT 2.2.

The error often manifests during a GWT Production mode compilation as:

[ERROR]  Internal compiler error
java.lang.IncompatibleClassChangeError: Found interface com.google.gwt.core.ext.typeinfo.JClassType, but class was expected

The Fallout

Because of this API change, most GWT plug-in libraries must be recompiled to GWT 2.2, and the resulting JAR will not be compatible with versions of GWT older than 2.2. In my case, this affected all the plug-ins I was using.

On the plus side, many GWT plug-in developers have already noticed the issue and begun issuing new versions. For example, if you are using Ext GWT, Sencha just released a new version this morning that is compatible with GWT 2.2. Bst-player, a plug-in I have contributed to, has also been updated for GWT 2.2.

Unfortunately, Google Maps, one of the most commonly used plug-ins, has not yet been updated and is therefore not currently compatible with GWT 2.2, as described in this bug report (please “Star” this issue if you have a G-mail/Google account!). If you rely on Google Maps in your GWT application, I strongly recommend you hold off upgrading to GWT 2.2. If you refer to the ticket, a user has posted their own GWT 2.2-compiled JAR, but this is not an official release.

All or Nothing

The major problem with this update is that it forces developers to update GWT and all plug-ins at the same time. If you upgrade to GWT 2.2, you are required to update all of your plug-in libraries and if, as in the case of Google Maps, there is no such update available, then you cannot upgrade at this time. Alternatively, if you keep the older version of GWT, then you cannot upgrade any of your plug-ins since the new versions will not be compatible with versions of GWT older than 2.2.

Conclusion

When I upgraded from GWT 1 to 2.0, a much more significant process, most plug-ins still worked, albeit with some issues. The fact that the GWT 2.2 upgrade completely breaks existing plug-ins is a serious issue, one I hope Google does not repeat in the future. With any luck, this is not a sign of things to come, and Google will consider supporting existing software in the future.

I'm Speaking at TheServerSide Java Symposium Reminder: Jeanne and I are both presenting at TheServerSide Java Symposium next week. My lecture is entitled “GWT Roundup: An Overview of Google’s Web Toolkit and Hybrid Integration” and Jeanne’s presentation is called “Throw Away All The Rules. Now What Process Do You Follow?.” The conference is being held in Las Vegas and it’s not too late to register to attend.

Google Releases GWT Designer

Posted on by
5

Last week, Google released the GWT 2.2 update. While this was a relatively minor update, at least compared to previous version updates, there was one new feature mentioned in the release notes that was much needed: GWT Designer.

UiBinder’s Missing Cousin

The GWT 2.0 version saw the release of the UiBinder framework, a technique for creating GWT components in HTML, analogous to building applications in MXML over ActionScript in Flash/Flex. For example, the following UiBinder snippet creates a GWT panel and list box in an HTML-based template:

<ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'    xmlns:g='urn:import:com.google.gwt.user.client.ui'>
       <g:HTMLPanel>
              Hello, <g:ListBox ui:field='listBox' visibleItemCount='1'/>.
       </g:HTMLPanel>
</ui:UiBinder>

What was severely lacking in the GWT 2.0, though, was the ability to edit this layout using a visual tool. There was really no compelling reason to switch to UiBinder, since it required learning a new syntax with limited benefits over writing it directly in Java.

Enter GWT Designer, now included in the Eclipse GWT 2.2 plugin, which allows you to create UiBinder components directly using a visual editor! Below is a sample screen-shot from a UiBinder class created in GWT Designer:

GWT Designer

But wait, there’s more!

GWT Designer is actually part of the WindowBuilder Pro family of graphical editors that includes SWT Designer and Swing Designer. Google offers the option of downloading the full stand-alone application, which includes support for 3rd party GWT add-ons such as GWT-Ext, GXT and SmartGWT.

With the GWT 2.2 release, Google also added support for HTML5, although it is marked as experimental/beta for the time being. To some surprise, they also deprecated support for Java 1.5 so if you have not upgraded to Java 1.6 yet, you will now get warnings in your application. Overall, the GWT 2.2 release helps to round out the GWT feature set leading to more powerful and easier to use tools.

I'm Speaking at TheServerSide Java Symposium Reminder: Jeanne and I are both presenting at TheServerSide Java Symposium next month. My lecture is entitled “GWT Roundup: An Overview of Google’s Web Toolkit and Hybrid Integration” and Jeanne’s presentation is called “Throw Away All The Rules. Now What Process Do You Follow?“. The conference is being held in Las Vegas and it’s not too late to register to attend!