Archive for the ‘Google App Engine’ Category

[GWT] Table with pagination and one sortable column

April 10th, 2011 No comments

I just added a very basic GWT project to my github account to display a table with pagination and one sortable column.
The code is mostly based on the official GWT tutorial :

I basically just added the SimplePage element to handle pagination :

SimplePager pager = new SimplePager();

Source :
Demo :

Categories: Git, Google App Engine, GWT, SCM Tags:

How to rollback a transaction in GAE

April 10th, 2011 No comments

This has nothing to do with JPA.
I was trying to deploy a GWT webapp to GAE when I suddenly got an error.
As a remedy, i got the message :
" Error posting to URL:
409 Conflict
Another transaction by user xxxxx is already in progress for this app and major version. That user can undo the transaction with's "rollback" command."

After digging into Google a bit, I found that the way to launch that rollback command under Windows is the following :
1) Figure out where the Google App Engine Java SDK directory is.
In my case, it’s under the Eclipse plugins directory :

The bin folder contains the appcfg.cmd command.

2) Under a DOS command prompt, go to the workspace folder of your project and launch the following command :
"D:\Dev\eclipse-jee-helios-SR1-win32\plugins\\appengine-java-sdk-1.4.2\bin\appcfg" rollback war

After that, you can try to deploy the app again and it should work.

Links :

Categories: Google App Engine, GWT Tags:

[Tutorial] Create your first GWT project and deploy it to GAE

April 9th, 2011 No comments

Here is a first quick and simple tutorial on how to develop and deploy your very first GWT web application to Google App Engine.

Requirements :
Google Web Toolkit plugin for Eclipse
A Google App Engine account + GMAIL account

So here are the steps :
Read more…

Categories: Google App Engine, GWT, Tutorials Tags:

I am not a GAE virgin anymore

January 30th, 2010 No comments

Well, I do not have much spare time to take a deep look at all the new technologies that come around but i always try to check at least the minimum.

Google App Engine offers a nice tutorial :

I did not run into any major problem.

The result is a very basic and classic guestbook application.

Building and uploading the web application from Eclipse to the App Engine is a piece of cake. You must first receive a code on your phone in order to create an application ID :


You can see it here :

I am looking forward for more fun with GAE in the near future, when I have the time.

Categories: Google App Engine, iPhone Tags: