Implementing Data Partitioning

public class ConsistentHashRing<T> {
    private final SortedMap<Long, T> ring = new TreeMap<>();
    private final int vnodesPerNode;

    public ConsistentHashRing(int vnodesPerNode) { this.vnodesPerNode = vnodesPerNode; }

    public void addNode(T node) {
        for (int i = 0; i < vnodesPerNode; i++) {
            ring.put(hash(node + "#" + i), node);
        }
    }

    public T getNode(String key) {
        if (ring.isEmpty()) return null;
        long h = hash(key);
        SortedMap<Long, T> tail = ring.tailMap(h);
        Long target = tail.isEmpty() ? ring.firstKey() : tail.firstKey();
        return ring.get(target);
    }

    private long hash(String s) {
        return Hashing.murmur3_128().hashString(s, StandardCharsets.UTF_8).asLong();
    }
}