JavaFX + WebStart + Web Services + GlassFish = One cool client app

In this post I will give an overview of the architecture that I've used to supply a connected thick (JavaFX) client application to a customer.

Here is the scenario: our company has an important customer who wishes to access and view some real-time data related to their business.

After some thought we've decided that the ideal platform for the client app is JavaFX (eye candy), the client deployment method is WebStart and we'll provide the data to the client via a SOAP Web Service. Easier said than done it turns out :)

There are a few issues with this set-up.

CLIENT:
The JavaFX client app can be written without major problems (see my previous posts about my beef with JavaFX tools) but I've found it best to create separate Java module to handle the WS communication. This is also useful since Maven doesn't seem to be able to build mixed source trees. Therefor the client app is composed of two separate JARs:
- Java library to handle WS client code generation and some utilities that are easier written in Java
- JavaFX GUI client that depends on the Java library

SERVER:
Simple enough Web Service deployed on GlassFish v2.1 JavaEE 5. Nothing special to note here.

DEPLOYMENT:
This was one of the trickiest parts. Since we have a number of servers (dev, test, stage, production, etc.) and we want a client which is downloaded from a specific server to connect to the WebService running on that same server. This we achieved by using a servlet to dynamically generate the JNLP file for the WebStart deployment. The servlet plugs the correct values into the JNLP for two things:
- where the client jars are located (i.e. codebase)
- a run-time property for the client specifying the WS location
The client (once launched) uses the WS location property to connect to the correct web service.
The servlet gets this information from system properties which can be easily set using the GlassFish web admin console. This means that we compile the code once and deploy it to any GlassFish server and all works well as long as we don't forget to add the two properties to the server.