no need to invoke slaveDown(). also some non-functional cleanup

src/main/java/org/redisson/connection/ElasticacheReplicationGroupConnectionManager.java

@@ -27,6 +27,7 @@ import org.redisson.MasterSlaveServersConfig;
 import org.redisson.client.RedisClient;
 import org.redisson.client.RedisConnection;
 import org.redisson.client.RedisConnectionException;
+import org.redisson.client.RedisException;
 import org.redisson.client.protocol.RedisCommands;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -34,6 +35,13 @@ import org.slf4j.LoggerFactory;
 import io.netty.util.concurrent.GlobalEventExecutor;
 import io.netty.util.concurrent.ScheduledFuture;
 
+/**
+ * {@link ConnectionManager} for AWS ElastiCache Replication Groups. By providing all nodes
+ * of the replication group to this manager, the role of each node can be polled to determine 
+ * if a failover has occurred resulting in a new master.
+ *
+ * @author Steve Ungerer
+ */
 public class ElasticacheReplicationGroupConnectionManager extends MasterSlaveConnectionManager {
 
     private static final String ROLE_KEY = "role:";
@@ -64,10 +72,14 @@ public class ElasticacheReplicationGroupConnectionManager extends MasterSlaveCon
 
             Role role = determineRole(connection.sync(RedisCommands.INFO_REPLICATION));
             if (Role.master.equals(role)) {
+                if (currentMaster.get() != null) {
+                    throw new RedisException("Multiple masters detected");
+                }
                 currentMaster.set(addr);
                 log.info("{} is the master", addr);
                 this.config.setMasterAddress(addr);
             } else {
+                log.info("{} is a slave", addr);
                 this.config.addSlaveAddress(addr);
             }
         }
@@ -99,20 +111,20 @@ public class ElasticacheReplicationGroupConnectionManager extends MasterSlaveCon
             public void run() {
                 try {
                     URI master = currentMaster.get();
+                    log.debug("Current master: {}", master);
                     for (URI addr : cfg.getNodeAddresses()) {
                         RedisConnection connection = connect(cfg, addr);
                         String replInfo = connection.sync(RedisCommands.INFO_REPLICATION);
                         log.trace("{} repl info: {}", addr, replInfo);
 
                         Role role = determineRole(replInfo);
-                        log.debug("Current master: {} / node {} is {}", master, addr, role);
+                        log.debug("node {} is {}", addr, role);
                         
                         if (Role.master.equals(role) && master.equals(addr)) {
                             log.debug("Current master {} unchanged", master);
                         } else if (Role.master.equals(role) && !master.equals(addr) && currentMaster.compareAndSet(master, addr)) {
                             log.info("Master has changed from {} to {}", master, addr);
                             changeMaster(MAX_SLOT, addr.getHost(), addr.getPort());
-                            slaveDown(MAX_SLOT, master.getHost(), master.getPort());
                             break;
                         }
                     }
@@ -125,13 +137,12 @@ public class ElasticacheReplicationGroupConnectionManager extends MasterSlaveCon
     }
 
     private Role determineRole(String data) {
-        String[] lines = data.split("\\r\\n");
-        for (String s : lines) {
+        for (String s : data.split("\\r\\n")) {
             if (s.startsWith(ROLE_KEY)) {
                 return Role.valueOf(s.substring(ROLE_KEY.length()));
             }
         }
-        throw new RuntimeException("Cannot determine role from " + data);
+        throw new RedisException("Cannot determine node role from provided 'INFO replication' data");
     }
 
     private MasterSlaveServersConfig create(ElasticacheReplicationGroupServersConfig cfg) {