Added MurmureHash as sharding algo.

src/main/java/redis/clients/jedis/ShardedJedis.java

@@ -5,6 +5,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import redis.clients.util.Hashing;
 import redis.clients.util.ShardInfo;
 import redis.clients.util.Sharded;
 
@@ -13,6 +14,10 @@ public class ShardedJedis extends Sharded<Jedis> {
 	super(shards);
     }
 
+    public ShardedJedis(List<ShardInfo> shards, Hashing algo) {
+	super(shards, algo);
+    }
+
     public String set(String key, String value) {
 	Jedis j = getShard(key);
 	return j.set(key, value);

src/main/java/redis/clients/util/Hashing.java

@@ -0,0 +1,79 @@
+package redis.clients.util;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public abstract class Hashing {
+    public static final Hashing MURMURE_HASH = new Hashing() {
+	public long hash(String key) {
+	    // 'm' and 'r' are mixing constants generated offline.
+	    // They're not really 'magic', they just happen to work well.
+	    byte[] data = key.getBytes();
+	    int seed = 0x1234ABCD;
+	    int m = 0x5bd1e995;
+	    int r = 24;
+
+	    // Initialize the hash to a 'random' value
+	    int len = data.length;
+	    int h = seed ^ len;
+
+	    int i = 0;
+	    while (len >= 4) {
+		int k = data[i + 0] & 0xFF;
+		k |= (data[i + 1] & 0xFF) << 8;
+		k |= (data[i + 2] & 0xFF) << 16;
+		k |= (data[i + 3] & 0xFF) << 24;
+
+		k *= m;
+		k ^= k >>> r;
+		k *= m;
+
+		h *= m;
+		h ^= k;
+
+		i += 4;
+		len -= 4;
+	    }
+
+	    switch (len) {
+	    case 3:
+		h ^= (data[i + 2] & 0xFF) << 16;
+	    case 2:
+		h ^= (data[i + 1] & 0xFF) << 8;
+	    case 1:
+		h ^= (data[i + 0] & 0xFF);
+		h *= m;
+	    }
+
+	    h ^= h >>> 13;
+	    h *= m;
+	    h ^= h >>> 15;
+
+	    return h;
+	}
+    };
+    public static final Hashing MD5 = new Hashing() {
+	private MessageDigest md5 = null; // avoid recurring construction
+
+	public long hash(String key) {
+	    if (md5 == null) {
+		try {
+		    md5 = MessageDigest.getInstance("MD5");
+		} catch (NoSuchAlgorithmException e) {
+		    throw new IllegalStateException(
+			    "++++ no md5 algorythm found");
+		}
+	    }
+
+	    md5.reset();
+	    md5.update(key.getBytes());
+	    byte[] bKey = md5.digest();
+	    long res = ((long) (bKey[3] & 0xFF) << 24)
+		    | ((long) (bKey[2] & 0xFF) << 16)
+		    | ((long) (bKey[1] & 0xFF) << 8) | (long) (bKey[0] & 0xFF);
+	    return res;
+	}
+    };
+
+    public abstract long hash(String key);
+}

src/main/java/redis/clients/util/Sharded.java

@@ -10,15 +10,19 @@ import java.util.TreeMap;
 
 public abstract class Sharded<T> {
     public static final int DEFAULT_WEIGHT = 1;
-    private static MessageDigest md5 = null; // avoid recurring construction
     private TreeMap<Long, ShardInfo> nodes;
     private int totalWeight;
     private Map<ShardInfo, T> resources;
+    private Hashing algo = Hashing.MD5;
 
     public Sharded(List<ShardInfo> shards) {
 	initialize(shards);
     }
 
+    public Sharded(List<ShardInfo> shards, Hashing algo) {
+	initialize(shards);
+    }
+
     private void initialize(List<ShardInfo> shards) {
 	nodes = new TreeMap<Long, ShardInfo>();
 	resources = new HashMap<ShardInfo, T>();
@@ -62,21 +66,7 @@ public abstract class Sharded<T> {
     }
 
     private Long calculateHash(String key) {
-	if (md5 == null) {
-	    try {
-		md5 = MessageDigest.getInstance("MD5");
-	    } catch (NoSuchAlgorithmException e) {
-		throw new IllegalStateException("++++ no md5 algorythm found");
-	    }
-	}
-
-	md5.reset();
-	md5.update(key.getBytes());
-	byte[] bKey = md5.digest();
-	long res = ((long) (bKey[3] & 0xFF) << 24)
-		| ((long) (bKey[2] & 0xFF) << 16)
-		| ((long) (bKey[1] & 0xFF) << 8) | (long) (bKey[0] & 0xFF);
-	return res;
+	return algo.hash(key);
     }
 
     private Long findPointFor(Long hashK) {