The most basic implementation is the SimpleFileVersionsController. It just stores the content. This class is used as a basis for the ZipFileVersionsController and Git versions controller.
Description of fitnesse.wiki.fs.VersionsController
To create a version controller 3 things are important:- The pages should be stored in a File system. The filesystem based wiki page is currently the only supported page type (but you're free to create your own)
- You'll need to implement the fitnesse.wiki.fs.VersionsController interface.
- To support recent changes you'll have to provide a class that implements the fitnesse.wiki.RecentChanges interface.
The VersionsController interface is quite straightforward. All the relevant information is provided through the fitnesse.wiki.fs.FileVersion interface. This interface provides the file name, content, author and time information.
The VersionsController interface consists of the following methods:
VersionInfo makeVersion(FileVersion... fileVersion) throws IOException;Create a new version/revision. This is typically called then a page is saved. Each FileVersion contains infomation about the file that is to be saved, the author and the content. Time information is usually less important. It might be that the author information is taken from the first file version provided (since all changes are to be saved as one commit anyway). Note that, since files are saved in directories, the directories are not mentioned as files-to-be-saved. It's up to the versions controller to take care of this.
FileVersion[] getRevisionData(String revision, File... files);Get a specific version of the files requested, given a revision indentifier. The label is either a property also provided by the VersionInfo object (typically name) or null, denoting the most recent version.
Collection<? extends VersionInfo> history(File... files);Obtain the history of a page. The history is as big as the depth set by setHistoryDepth(int) (see below).
void addDirectory(FileVersion... files) throws IOException;Create a new (versioned) directory. This operation is called from the http://files/ handlers.
void rename(FileVersion fileVersion, File originalFile) throws IOException;Rename a versioned file. This operation is called from the http://files/ handlers.
void delete(FileVersion... files);Delete the page. The author has to be set to the user performing the delete operation.
void setHistoryDepth(int historyDepth);Configure the depth for which versions need to be stored (in case of zip files) or the history depth for which changes are fetched (see history() above)
What happened to CmSystem?
In older versions the convention was to create a CmSystem class: a class that fulfilled the CmSystem protocol. Although this appeared to work fine on paper the real world version had some downsides. For one it was not in control with the saving of the content, now the VersionsController is in charge of this. Also the protocol was quite cumbersome and it involved Java introspection logic to get it working. Why does your wiki page have to "know" about version control anyway...The VersionsController solution will be more solid can be made to provide generic solutions towards version control in FitNesse.