I'm trying to implement the Chord protocol in order to quickly lookup some nodes and keys in a small network. What I can't figure out is ... Chord cosideres the nodes and keys as being placed on a cirlce. And their placement dictated by the hash values obtained by applying the SHA-1 hash function. How exactly do I operate with those values? Do I make them as a string de9f2c7f d25e1b3a fad3e85a 0bd17d9b 100db4b3 and then compare them as such, considering that "a" < "b" is true ? Or how? How do I know if a key is before or after another?
Since the keyspace is a ring, a single value can't be said to be greater than another, because if you go the other way around the ring, the opposite is true. You can say a value is within a range or not. In the Chord DHT, each server is responsible for the keys within the range of values between it and its predecessor.
I would advise against using strings for the hash values. You shouldn't use the hashCode function for distributed systems, but you need to math on the hash keys when adding new nodes. You could try converting the hashes into BigIntegers instead.