EclipseSource Blog » Rüdiger Herrmann

High availability clustering for RAP/RWT in Eclipse Juno

Rüdiger Herrmann — Thu, 16 Jun 2011 09:12:24 +0000

Computer cluster, taken from http://thefullwiki.org/Parallel_programming

While most of us are busy with that latest bits of the Indigo release, some have the joy to work on one of the next new features in RAP: support for high availablity clusters.

Let me briefly mark out what we mean by clustering support and what we don’t. Load balancing clusters are used if you whish to provide your applications to a large number of users. If your application provides critical servies you may also want to make it fail safe by running it in a high availablity cluster.

A high availability cluster operates by having redundant nodes. So that if one node crashes, the service as a whole is unafected as other nodes take over the work. Whereas load balancing RAP applications is possible since ever, failover clusters put further requirements on the framework.

To be able to migrate sessions between nodes in a cluster, all session data has to be serializable. Also, the current implementation preserves the server-side execution flow within a UIThread in order to single-source RCP applications. These two form the main work areas.

All session data must be prepared for distributing sessions among cluster nodes for failsafe operation.
A new life cycle for processing requests without a UIThread was implemented and RAP can be configured to run with either of them.

The new life cycle also makes it easier to access security or transaction contexts and is conform to the JEE Specification. If you don’t use blocking dialogs or workbench features and want to be able to eventually run your application in a cluster – then this is for you.

For more details, see the RAP Wiki.

Drag and Drop in Eclipse RAP

Rüdiger Herrmann — Fri, 27 Nov 2009 17:06:11 +0000

Support for drag and drop just made it into the RAP source code repository. You can use the same API as known from SWT and thus re-use even more code when single-sourcing RCP applications.
It will be available in the M4 build. In the meanwhile you can check out the sources from CVS and explore the new functionality online (go to the List page).

There are still some things left to do, for more details see this bug. We would be very happy to gain feedback about how your existing drag and drop code works on RAP. In case something doesn’t work as expected, please drop us a line or open a bug.

Spread Sheet in the RAP Incubator

Rüdiger Herrmann — Tue, 17 Nov 2009 14:46:24 +0000

I am very pleased to see that the first code arrived in the RAP incubator project. The contribution consists of the very early steps towards a spread sheet component.

It is still in the proof of concept phase. The goal so far was to find out whether a spread sheet that is composed of existing widgets could work with regard to performance and usability. This seems to work out rather well. As a consequence of composing the spread sheet of existing widgets the same code runs on SWT as well.

In case you whish to play around with it or even contribute, the source code can be obtained from CVS and resides in the incubator/spreadsheet module.