基于Eclipse RCP功能的项目

Question

Hello to understand how to work with features I build this plugins, feature and App.

myPluginOne - One.class with hello world print method. myPluginTwo - Two.class with hello Galaxy print method. myFeature - Included plugins, myPluginOne and myPluginTwo.

myApp - Eclipse RCP Application, product configuration is feature based (selected in overview tab). I added in tab "Contents" of the product file the feature "myFeature".

Ok, now I created in "myApp" a new Class with a method to execute this Code.

One o = new One();
o.print();

Now the completely brain destroying begins. "One can not be resolved to a type". Why not? I added "myFeature" to myApp and myFeature includes "myPluginOne" so why its not working?

Export the right packages right? Ok, now I export the right package in "myPluginOne".Tab Runtime -> Exported Packages -> Add

"One can not be resolved to a type"

Hmm what to do? Ok let say import package in myApp. Done, open plugins.xml -> Dependencies Tab - Imported Packages -> Add

Now it works!

But hey wait, let do something special. Now I delete the entire Feature "myFeature" and remove it from "myApp".

Its still works! So, like myFeature is completely useless. To run in this way I dont need it. Why I need any Feature Projects, at the end of the day I added plugins...

Pls after I read like entire Internet about features. Pls some one explain me.

How to use Features correctly.

Answer 1

Features are a way to group plugins together and are most useful when you have a large RCP with lots of plugins. They are nothing to do with the export/import package part of the plugin system.

Eclipse itself is a good example of using features. This is a screen shot of the features in my Eclipse installation:

This feature page of the installed software dialog gives a good overview of what Eclipse features I have.

Additionally when using the product build if you use 'plugin based' you will end up having to list a large number of plugins which can be hard to manage. Using a 'feature based' build you will only have a small number of features. For example this is one of my (quite large) e4 RCP content configurations: The plugin based equivalent would have over a hundred plugins listed.