Base executor interface that specifies the execute() method and various helper methods
Interface that acts as a common base for Executors that implement all ActionModes.
Config Singleton that stores paths to the database and the papio directory
Enum that models the actions that are applicable on a root category
Enum that models which part of the database are to be changed
Exception that gets thrown whenever the program should abort
Exception that is thrown whenever the root help message should be printed and the program should terminate