Moving toward bundles - OSGi in Action - page 206

Figure 6.5 JAR-to-bundle cheat sheet

OK , you know how to take a single JAR file and turn it into a bundle, but what about a
complete application? You could take your existing JAR , EAR , and WAR files and turn
them all into bundles; or you could choose to wrap everything up as a single application
bundle. Surely you can do better than that. What techniques can you use to bundle up
an application, and what are the pros and cons? For the answers to this and more, read on.

6.2 Splitting an application into bundles

Most applications are made up of one or more JAR files. One way to migrate an appli-
cation to OSG i is to take these individual JAR files and convert each of them into a
bundle using the techniques discussed in the previous section. Converting lots of JAR
files is time consuming (especially for beginners), so a simpler approach is to take
your complete application and wrap it up as a single bundle. In this section, we'll show
you how to start from such a single application bundle and suggest ways of dividing it
further into multiple bundles. Along the way, we'll look at how you can introduce
other OSG i features, such as services, to make your application more flexible. Finally,
we'll suggest places where it doesn't make sense to introduce a bundle.
Let's start with the single application bundle or so-called mega bundle .

6.2.1 Making a mega bundle

A mega bundle comprises a complete application along with its dependencies. Any-
thing the application needs on top of the standard JDK is embedded inside this bundle