Undo quick hack with JFS 2017 speaker data

[ascheman]

Found a really ugly quick hack in the code. Took me 2 hours to fix and circumvent this. Nevertheless even my workaround is still a large code smell and should be refactored.

In general we should think about using more strong types, even in internal interfaces to avoid such problems in the future. And, of course, we should provide better (unit) tests and keep our abstractions clear!!!

The problem occured with speaker pictures in the SpeakerImageServiceImpl. For Heise conferences we have them available as a byte stream (and know the filename additionally). For DOAG (Formes) conferences, i.e., Java Forum Stuttgart 2017, we have the filename but treat it as the byte stream. So the code needed to detect this and extract the file contents by the file name given in the byte stream. Groovy enabled this by having methods with default arguments (the filename) which allowed to apply a single argument to the method call. Even if it was the filename it was treated as content. We could have prevented this by

• using strong typed parameters
• providing image data from the extractor component to the image service (image service should not even know about the repository details)

which we should both do in the future.