Does Java have a HashMap with reverse lookup?
There is no such class in the Java API. The Apache Commons class you want is going to be one of the implementations of BidiMap. As a mathematician, I would call this kind of structure a bijection.
There is no such class in the Java API. The Apache Commons class you want is going to be one of the implementations of BidiMap. As a mathematician, I would call this kind of structure a bijection.