Encapsulating Java Preferences API

Question

I used to have a custom preferences class for my applications. For my next hobby project i wanted to switch to the Preferences API. But the put and get functions require a default value and i do not want to spread default values all over the source files. Even though my project is small i can not imagine changing default values all over the source code. How do you guys use the api? I am thinking of wrapping the preferences api in another class but then what is the point of using the API because it only takes away the burden of saving the file to disk, which isn't that hard using serialization? Am i missing the point?

Answer 1

You're mixing a few concepts here. The default given in the code should be specific to the local situation as a 'reasonable default'. If you want to have application-wide defaults, then you need a preference-provider that allows you to hook in both the default preferences and an overlaid user-preferences. Something that may be a worthwhile project in itself.

Oh, and "reasonable defaults" is a great way to avoid configuration when it's not necessary but allow the user or packager to provide better values when needed.

@comment, I think I understand.

By 'local situation' I mean in the context of the code. For your GUI, you need a value for display that represents whatever the thread is using. Therefore I'd use something like Worker.DEFAULT_TIMEOUT. Your worker would use the same value internally as the default. That way you are retrieving the configured value or the worker's default when you are setting the worker's behavior.

Answer 2

then you might want to take full control over how Preferences should follow your desired storage by implementing AbstractPreferences. You can see a linux based implementation here:

http://www.docjar.com/html/api/java/util/prefs/FilePreferencesImpl.java.html

Good luck!