When to choose "Generate an activator..." when creating a new Eclipse plugin project

Question

There are lots of Eclipse RCP tutorials that begin with the obvious first step: "Create a new plugin project..."

It seems that approx. 70% of them specify checking the "Generate an activator, a Java class that controls the plug-in life cycle". The others specifically say don't check that toggle.

alt text http://img179.imageshack.us/img179/6710/newpluginoptions.png

Its not clear to me, what generating an activator class does for you, when you need one, and when you don't.

For being a prominent option you get every time you create a new plugin project (it seems to be set on by default) this option isn't very well explained anywhere that I have found.

Any advice/rules of thumb on choosing this option when creating Eclipse plugin projects?

Answer 1

One way to find out is to look at the generated class. Turns out that it is a subclass of AbstractUIPlugin. Check out the JavaDoc, it provides services like preference management, image registry and the like. If you need any of this, you may want to use it. It is a subclass of Plugin, which kind of makes sense.

Also, it implements BundleActivator, which has some useful JavaDoc. This provides you with stubs for start() and stop(), which allows you to hook your own code in here. It also generates a static convenience method getDefault(), which gives you the Activator. And that's all there is to it.