A number of services have been provided to help simplify the code. The code for each service is encapsulated in a singleton object (an instantiation of the relevant class). The singleton design pattern allows the definition of a class that can only be instantiated once, and that instance effectively exists as a global object available to all the code without having to be passed around as a parameter. Singletons are a little anti-OO, but provided they are used judiciously are not necessarily a bad thing, and can be very useful in certain circumstances.
Services provided are: