+ add hsetNX to hash commands

+ add jedis and jredis impl for hsetNx

spring-datastore-redis/src/main/java/org/springframework/datastore/redis/connection/RedisHashCommands.java

@@ -34,6 +34,8 @@ public interface RedisHashCommands {
 
 	Boolean hSet(String key, String field, String value);
 
+	Boolean hSetNX(String key, String field, String value);
+
 	String hGet(String key, String field);
 
 	List<String> hMGet(String key, String... fields);

spring-datastore-redis/src/main/java/org/springframework/datastore/redis/connection/jedis/JedisConnection.java

@@ -329,6 +329,19 @@ public class JedisConnection implements RedisConnection {
 		}
 	}
 
+	@Override
+	public Boolean hSetNX(String key, String field, String value) {
+		try {
+			if (isQueueing()) {
+				transaction.hsetnx(key, field, value);
+				return null;
+			}
+			return JedisUtils.convertCodeReply(jedis.hsetnx(key, field, value));
+		} catch (Exception ex) {
+			throw convertJedisAccessException(ex);
+		}
+	}
+
 	@Override
 	public String get(String key) {
 		try {

spring-datastore-redis/src/main/java/org/springframework/datastore/redis/connection/jredis/JredisConnection.java

@@ -788,6 +788,11 @@ public class JredisConnection implements RedisConnection {
 		}
 	}
 
+	@Override
+	public Boolean hSetNX(String key, String field, String value) {
+		throw new UnsupportedOperationException();
+	}
+
 	@Override
 	public List<String> hVals(String key) {
 		try {