Introduction
This is the second in a series of three blogs describing a step-by-step approach to building and deploying GWT applications in the
SpringSource dm Server™. The first blog looked at the process of creating a simple WAR file from a sample GWT application. This next blog will look at turning the WAR file we created in
Part 1 into a
"Shared Libraries" WAR. This means that we are going to externalize the GWT dependencies of our application into an OSGi bundle so that it can be shared by any number of GWT applications. You can think of it as extending our dm Server with GWT remoting capabilities.
As mentioned in Part 1, I am not using the Spring Framework in this second blog posting, rather I am focusing on the SpringSource dm Server™ and SpringSource Tool Suite to deploy "pure" GWT.
Please also see Part 1 for the background to the GWT StockWatcher sample and the software I'm using.
Quick Catch Up
In
Part 1, we built the GWT StockWatcher sample application from scratch as an Eclipse project and then generated the code into a Dynamic Web project which we then deployed into dm Server. Finally, we exported the Dynamic Web project into a WAR file and deployed it outside of STS.
The step by step approach described here will build on what we did in Part 1, rather than start over. The only thing we did in Part 1 that we're now going to change is to remove the explicit dependency on the gwt-servlet.jar library.
Step 1: Turn our GWT dependency into a OSGi bundle
Firstly, a little more background. The whole concept of the "Shared Libraries" approach is to create a map of dependencies within the dm Server using explicit imports and exports between OSGi bundles. With a small WAR such as our StockWatcher sample, this is mostly just an interesting academic exercise. However, given that many commercial web projects ship in large WAR files which are packaged with tens or even hundreds of dependent jar files, breaking out these dependencies into shareable resources not only makes sense from a footprint perspective, but also makes the packaging, versioning and maintenance of the applications significantly less painful.
The good news is that much of work to create these dependencies has already been done for you. The SpringSource Enterprise Bundle Repository contains "bundlized" versions of most common libraries. However, at the time of writing, our GWT dependency is an example of a library that you have to turn into a bundle…
