CODEWITHSUNDEEP
javapreferences
chris
chris

Reputation: 171

Load Preferences for nonexistent class

Our program stores user settings using the Preferences class, accessed via Preferences.userNodeForPackage(). We just finished a major refactor and discovered that all of the user settings are forgotten post-refactor, because the class passed to userNodeForPackage() is different. E.g. instead of org.foo.MyClass we now have org.foo.bar.MyClass.

I want to "import" the old Preferences so our users don't notice things being forgotten. If necessary I can manually copy individual key/value pairs across from the old Preferences object to a new one, but I must be able to get that old Preferences object first. Without access to the old class, I don't see how this is possible.

Am I missing something? I see the Preferences.node() / Preferences.nodeExists() methods which seem promising, except that they only operate on an existing Preferences that contains the desired node. Thus we'd have to be able to get a tree that contains the old root node, and we have no classes above where that old node was (part of the point of refactoring was de-flattening our hierarchy).

I'd really rather not pollute our nice clean source code with dummy files, just so we can access old preferences. Can you assign a package to an anonymous class generated at runtime, perhaps? Or is there some other way to get a Preferences object for a specific package short of passing in the class for that package?

Thanks in advance.

Upvotes: 0

Views: 64

Answers (1)

chris
chris

Reputation: 171

RC's comment of using Preferences.userRoot() is what I needed -- that gets you the root of the entire Preferences tree, and you can then traverse it using Preferences.node() to get to whatever value you need. Thanks, RC!

Upvotes: 2

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