The RAP team started working on a new feature called ClientScripting. It’s still in it’s infancy and will not (yet) be part of the core framework , but its already very useable. The goal is to allow adding pieces of behavior to the client-components of RAP widgets. This makes it possible to have swift, dynamic user feedback in situations that require a certain amout of logic – so far a problematic scenario for RAP applications. It can be considered an alternative to custom widget development in many cases, and might also save some network traffic. We currently focus on the scenario of validating text input while typing, and will expand from there. Interactions between widgets are not yet possible, but is planned.

As you can test for yourself, the difference between server-side and client-side validation is quite noticeable.

When using ClientScripting, you will need to know very little JavaScript, and all API is as close to SWT as possible. The project has a wiki page with all further information you might need (including where to get the code). Note that you need RAP 1.5M6 or newer to use it. If you try it out, please consider giving some feedback, report bugs or file enhancement requests.

Tags: ajax, ClientScripting, demo, javascript, juno, news, rap

If you ever need a WYSIWYG editor in your RAP application, look no further.

I originally implemented this as an example of how JavaScript applications can be embedded in RAP as custom widgets. So if you have a similar scenario, you could also use this project as a template. The editor is fairly customizable, read the README for details. You can get the code on GitHub.

Tags: ajax, CKEditor, Custom Widget, javascript, rap, Rich Text Editor

The Enron Corporation was the American energy company that was involved in accounting fraud which led to the Enron scandal in 2001. During the investigation, large parts of the company’s email conversations were published. The result is that a huge, real-life data set including more than half a million emails from 150 Enron executives came into the public domain.

I thought that this data would be a good example to show the ability of the new Tree widget in RAP to display huge datasets.

It’s clear that you cannot create half a million UI elements in a browser without running out of memory. Neither can you load the entire dataset (> 2GB on disk) into memory on the server. You need a mechanism to load and display data on demand.

As of this week, the RWT Tree widget has full SWT.VIRTUAL support, i.e. it is capable of creating Tree items only at the moment they become visible. This feature is used by the JFace TreeViewer to request data from a lazy content provider on demand.

So, in order to make a complex data set accessible with a web UI, you just need to write an ILazyTreeContentProvider implementation. That’s about one screen of Java code, mostly copied from a JFace snippet. That’s all.

Check out the example on our online demo (navigate to the tab called Complex Data). The source code of this demo page is available on github.

Full SWT.VIRTUAL support for the Tree widget is available in CVS and will be part of RAP 1.5M1.

Tags: ajax, new and noteworthy, rap

A few weeks ago I showed you how easy it is to integrate jQuery into RAP using the browser widget. I’d like to show you another example of what can be integrated. Last time I created a carousel widget; this time the demo is something smaller but still really cool.

Yesterday I came across a github repository by Ryan McGeary. He has created a very clever jQuery plug-in called “timeago“. What this plug-in does is simple. It takes a timestamp and displays a text string instead of the stamp that describes the difference between the actual time and the one in the timestamp.  We’ve all seen the messages, “about a minute ago.”  The cool thing about this plug-in is that it refreshes automatically. I mean, it isn’t new to transform timestamps in this way, but it is usually done just once. So, when you visit a website in the morning and leave the tab open until evening, it still says something like, “The page was opened about minute ago” . This can’t happen with McGeary’s plug-in.

While having a jQuery plug-in is nice for javascript developers, it’s not as nice if you’re a Java Developer. But, fortunately we can integrate jQuery painlessly into RAP. As a result I wrote a RWT/SWT widget that simply maps the functionality of the timeago plug-in. You can set a date from the server and read the displayed text from the client.

If you like this idea you can grab the sources at github. Of course this is just a demo. Let me know if you would like to work with me on an implementation for productive use. Have fun with timeago

Tags: ajax, indigo, javascript, JQuery, rap, timeago, widget