Decorator pattern in reading configuration
Almost all applications have some configuration properties they use for various purposes. Typically you have Key/Value pairs representing the property names and values. Therefore, internally, a Properties or other Map is a good representation for these configuration settings.
So while there's a good way to store this data internally, there are tons of meduims to read it from: XML files, Properties file, Servlet init parameters, etc. Additionally, there are several ways to read multiple files. For example, given a directory load all files below it. Or load all resource files.
Say you have someConfigurationLoader interface. I'm theorizing that you could use the Decorator pattern with XMLConfigurationLoader, PropertiesConfigurationLoader, ServletConfigurationLoader, MultipleFileConfigurationLoader, ResourceConfigurationLoader, etc.
I'm having trouble coming up with the implementation for decorators like the MultipleFileConfigurationLoader and it's making me think that the Decorator pattern isn't applicable here. What do ya'll think?
