How to manage license banners in source files of Eclipse plug-in projects

Question

I'm about to release a set of Eclipse plug-ins as Open Source and noticed that most source code released under the LGPL/EPL contains a header banner in each file that refers to the license or contains the license itself.

Since adding these banners to each file manually seems to be a daunting and error-prone task, I was wondering whether there are any best practices regarding this task. Are there any tools or plug-ins for Eclipse that support the developer at adding and updating this kind of metadata?

Are there any best-practices when it comes to generated source code?

Any advice is much appreciated.

Edit: After looking around more closely, I found Copyright Wizard which is a Eclipse plug-in which also allows for updating existing license banners.

Answer 1

Concerning best practises, I believe you should have your license text in a separate file and have a build tool (ie ant) to add it at the beginning of all other files. Since you are talking about an open source project you would need a build process anyway for thinks like generating the javadocs, publishing releases etc.

BTW,ant tasks are simple Java classes so it should be easy to write one yourself if you don't find an ant plugin that does exactly that.

Coming to eclipse, to my knowledge, it cannot do something like this. The quickest way I can think of to do it is with bash (if you are using Linux). Assume the file msg contains the text you want to add at the beginning of every file.

1. Create a new directory to store the files:

   mkdir ~/outdir

2. Add the msg at the beginning of every file and put the result at the outdir

   for i in ls "*.java"; do cat msg $i > ~/outdir/$i ; done

Similarly you can write a command that does the same recursively, with an extra step to create the directory strucutre:

mkdir ~/outdir
for i in `find -type d | sed 's/\.//' | grep -v "^$"`; do mkdir ~/outdir$i; done
for i in `find -name "*.java"`; do cat msg $i > ~/outdir/$i ; done

Answer 2

A more Eclipse-like approach than the manual addition is the following, done via GUI in Eclipse. Note that these are the Linux / Windows menus; Mac is a bit different.

1. Open Windows->Preferences
2. Navigate to Java->Code Style->Code Templates
3. Edit the Comments->Files comment template to include your boilerplate.
   There are variables for the current year, file name, etc...

Note, also, that this is a solution for new files only; it's not going to help you with old files; for that, I would use something like idrosid's solution for your existing code

Answer 3

Eventually, I found Copyright Wizard which is a Eclipse plug-in which also allows for updating existing license banners.