A good solution to include some template text into a source file using SVN?

Question

I have a Java project in a SVN repository, with a bunch of .java files, each of those files has a licence agreement flower box at the top of the file (I have customers which have licenced the source as well as running the product).

Is there a good way to be able to modify / maintain the licence text in one place rather than having to update all the source files manually if it changes?

Looking at some similar (but not identical) questions it seems like SVN does not have this functionality out of the box - what other approaches would be most suitable?

Edit: Ideally the solution would act like the SVN keywords (Id, Author etc.) rather than being a build-time solution. The customer has access to the SVN repository too, so it would be ideal if the licence text was present in the SVN version of the file. I know SVN has commit triggers - what's a simple way to implement that?

Edit 2: Looking at the SVN hooks it doesn't look like what I'd like to do is possible. I guess build process that can be run when the text changes is ok - since it won't change too often.

Answer 1

Modify the source files that need to contain the text of the license to contain some token instead, and then move the license text to a single file that's kept in subversion. Finally, as part of your build process, add a step that substitutes the text of the license for the token. At my job, I do something along these lines using a combination of sed and make. You could then execute this single step before distributing the source to your customers.

Answer 2

ANT can do the substitution easily. Look into the <copy> target.