Optimize readability of the NOTICE file

[matthiasblaesing]

While looking into NETBEANS-827 it was found, that the NOTICE file is
difficult to read, as no clear sections were visible.

This adjust the output as such, that:

• the primary header is separated from the following entries by
  two empty lines
• all imported entries are normalized, so that multiple empty lines
  are collapsed into one empty line
• all imported entries are separated from each other by two empty
  lines

To illustrate here are the pre- and post picture:

notice-pre.txt
notice-post.txt

I tried to see what NETBEANS-827 is about and at first I did not even find the entry. The corresponding entry is:

Apache Commons Net
Copyright 2001-2017 The Apache Software Foundation

From my interpretation of the legal FAQ this is the correct form, but in the "pre" version is difficult to find.

[matthiasblaesing]

The filter in build.xml removes the two empty lines in the postprocessing from notice-temp to NOTICE. I only looked at the notice-temp output and just did a full build and also checked the final NOTICE file.

[emilianbold]

I don't see the primary header getting more lines. Other than that it's a good fix.

[matthiasblaesing]

Sorry - the wording was not precise. Please see the attached screenshot of the comparison:

• red is what I meant by "primary header" (the netbeans NOTICE) with the two empty lines
• blue are the imported entries from dependencies with the seperating empty lines

[emilianbold]

I see. I don't know if we must have some structure inside the NOTICE file but now that I look at this screenshot it would be even more readable if each entry would have some tabs in front.

Example:

Apache Ant
Copyright ...

    The sync task is based on code
    taken from etc etc


Apache Commons Compress
Copyright ...

    The file x/y/x has been derived
    from code found on example.com

[matthiasblaesing]

We don't "need" the structure, but we need to assemble a NOTICE file based on our dependencies (at least this is my current understanding) and it needs to be accepted by the reviewers. The final NOTICE file holds information for required notices from the codebase and the dependencies of the project, that are bundled with the files. See http://www.apache.org/dev/licensing-howto.html#alv2-dep for details.

The approach in netbeans (consisting of modules) was, that each module declares its dependencies (external/binaries) and for each dependency the license ("-license.txt" was recorded. This scheme was enhanced for apache netbeans, by also supporting an "-notice.txt" file, that holds required notice information.

The notice information of each included module is then merged into the global file, suppressing duplicates. The file is mostly copied verbatim (only multiple empty lines are collapsed into one). To make the suggested indention possible, there would need to be a fixed notice file format. This is not the case (as you saw in the ini4j case), so I stayed with this minimal formating, just makeing grouping of information visible.

[emilianbold]

OK, I don't have strong feelings about it. Just an extra newline doesn't seem to group very well to me, we might as well use '===' or something. But if it helps you pinpoint dependencies faster, it's fine.

[jlahoda]

Looks good to me.