Creates the directory content by creating a folder for each entry.
Mark all cached values out of date that happened after the timeOfEarliestChange.
Note: The individual implementations decide whether to invalidate the content of a folder. At the moment all implementations adhere to the >= timeOfEarliestChange rule, but this might change.
Sets how the sub-folder content shall be generated.
This works by specifying a factory, that spawns a new object for each subdirectory. You can chain those calls to set the content of sub-sub-folder and sub-sub-sub folders if the SubDirectoryT implementation supports chaining.
This directory generates years folders.