package redis.clients.jedis;
import redis.clients.jedis.exceptions.JedisAskDataException;
import redis.clients.jedis.exceptions.JedisClusterException;
import redis.clients.jedis.exceptions.JedisClusterMaxRedirectionsException;
import redis.clients.jedis.exceptions.JedisConnectionException;
import redis.clients.jedis.exceptions.JedisMovedDataException;
import redis.clients.jedis.exceptions.JedisRedirectionException;
import redis.clients.util.JedisClusterCRC16;
public abstract class JedisClusterCommand<T> {
private JedisClusterConnectionHandler connectionHandler;
private int commandTimeout;
private int redirections;
private ThreadLocal<Jedis> askConnection = new ThreadLocal<Jedis>();
public JedisClusterCommand(JedisClusterConnectionHandler connectionHandler,
int timeout, int maxRedirections) {
this.connectionHandler = connectionHandler;
this.commandTimeout = timeout;
this.redirections = maxRedirections;
}
public abstract T execute(Jedis connection);
public T run(String key) {
if (key == null) {
throw new JedisClusterException(
"No way to dispatch this command to Redis Cluster.");
}
return runWithRetries(key, this.redirections, false, false);
}
private T runWithRetries(String key, int redirections,
boolean tryRandomNode, boolean asking) {
if (redirections <= 0) {
throw new JedisClusterMaxRedirectionsException(
"Too many Cluster redirections?");
}
Jedis connection = null;
try {
if (asking) {
// TODO: Pipeline asking with the original command to make it
// faster....
connection = askConnection.get();
connection.asking();
// if asking success, reset asking flag
asking = false;
} else {
if (tryRandomNode) {
connection = connectionHandler.getConnection();
} else {
connection = connectionHandler
.getConnectionFromSlot(JedisClusterCRC16
.getSlot(key));
}
}
return execute(connection);
} catch (JedisConnectionException jce) {
if (tryRandomNode) {
// maybe all connection is down
throw jce;
}
releaseConnection(connection, true);
connection = null;
// retry with random connection
return runWithRetries(key, redirections - 1, true, asking);
} catch (JedisRedirectionException jre) {
if (jre instanceof JedisAskDataException) {
asking = true;
askConnection.set(this.connectionHandler
.getConnectionFromNode(jre.getTargetNode()));
} else if (jre instanceof JedisMovedDataException) {
// it rebuilds cluster's slot cache
// recommended by Redis cluster specification
this.connectionHandler.renewSlotCache();
} else {
throw new JedisClusterException(jre);
}
releaseConnection(connection, false);
connection = null;
return runWithRetries(key, redirections - 1, false, asking);
} finally {
releaseConnection(connection, false);
}
}
private void releaseConnection(Jedis connection, boolean broken) {
if (connection != null) {
if (broken) {
connectionHandler.returnBrokenConnection(connection);
} else {
connectionHandler.returnConnection(connection);
}
}
}
}