A few years back  I wrote some classes that do just what you're talking
about. The main class is LookupTable, which inherits from
AbstractLookupTable. Take a look at the JavaDoc to see if this is
something you could use. If so, the cost is $5 USD for this class and
some other utility classes. You can reach me privately at
tim@... . Make sure to include "[Utilities.java]" in the
subject line.