As an experienced Java programmer you know that the J2EE world introduced the concept of web-applications some time ago. Theses applications are packed as a .war archive and can be deployed on any J2EE-compliant servlet container.

Projector applications are similar to the web-applications but there are some fundamental differences that might indicate when it’s time for a Projector application and when you can stay with the good old web-applications.

First of all, web-applications normally don’t get changed after they have been deployed. If you want to change some pieces of text of a web page you have to make these changes locally and package and redeploy the whole application afterwards. The content of a Projector based applications resides in the underlying WebDAV repository and as such can be changed easily on the live site with any tools that allow accessing the repository.

Second, the Projector applications can rely on each other. You can split your application into small reusable pieces. This is a big advantage if you for example want to change the layout of different applications. You can define a basic layout application that other applications depend on. Think of some small applications like a guestbook, a forum and so on that share the same layout. Changes to the application defining the layout will affect both immediately. As you can even share processors you can achieve a much higher grade of reusability.

It can be distinguished between simple applications that can be assembled by using the processors that ship with Projector and more complex applications that require the extension of the Projector framework itself by adding custom classes.

We want to start with the first as this chapter will focus on assembling and deploying Projector applications.