Clustering and High Availability

public interface ClusterCommands {
    /**
     * Get cluster nodes information
     * @return Cluster nodes configuration and status
     */
    String clusterNodes();
    
    /**
     * Get cluster information and statistics
     * @return Cluster info including state, slots, and metrics
     */
    String clusterInfo();
    
    /**
     * Get cluster slots mapping
     * @return List of slot ranges and responsible nodes
     */
    List<Object> clusterSlots();
    
    /**
     * Get keys in specific cluster slot
     * @param slot Cluster slot number (0-16383)
     * @param count Maximum number of keys to return
     * @return List of keys in the slot
     */
    List<String> clusterGetKeysInSlot(int slot, int count);
    
    /**
     * Count keys in cluster slot
     * @param slot Cluster slot number
     * @return Number of keys in the slot
     */
    Long clusterCountKeysInSlot(int slot);
    
    /**
     * Get slot for key
     * @param key Redis key
     * @return Cluster slot number for the key
     */
    Long clusterKeySlot(String key);
    
    /**
     * Initiate cluster failover
     * @return Status code reply
     */
    String clusterFailover();
    
    /**
     * Initiate cluster failover with options
     * @param failoverOption Failover type (FORCE or TAKEOVER)
     * @return Status code reply
     */
    String clusterFailover(ClusterFailoverOption failoverOption);
    
    /**
     * Forget cluster node
     * @param nodeId Node ID to forget
     * @return Status code reply
     */
    String clusterForget(String nodeId);
    
    /**
     * Meet new cluster node
     * @param ip Node IP address
     * @param port Node port
     * @return Status code reply
     */
    String clusterMeet(String ip, int port);
    
    /**
     * Reset cluster node
     * @param resetType Reset type (HARD or SOFT)
     * @return Status code reply
     */
    String clusterReset(ClusterResetType resetType);
    
    /**
     * Save cluster configuration
     * @return Status code reply
     */
    String clusterSaveConfig();
    
    /**
     * Set cluster slot state
     * @param slot Slot number
     * @param nodeId Node ID to assign slot
     * @return Status code reply
     */
    String clusterSetSlotNode(int slot, String nodeId);
    
    /**
     * Set slot as migrating
     * @param slot Slot number
     * @param nodeId Target node ID
     * @return Status code reply
     */
    String clusterSetSlotMigrating(int slot, String nodeId);
    
    /**
     * Set slot as importing
     * @param slot Slot number
     * @param nodeId Source node ID
     * @return Status code reply
     */
    String clusterSetSlotImporting(int slot, String nodeId);
    
    /**
     * Clear slot state
     * @param slot Slot number
     * @return Status code reply
     */
    String clusterSetSlotStable(int slot);
    
    /**
     * Replicate from master node
     * @param nodeId Master node ID
     * @return Status code reply
     */
    String clusterReplicate(String nodeId);
    
    /**
     * Get cluster node ID
     * @return Current node ID
     */
    String clusterMyId();
}

public class JedisCluster extends UnifiedJedis {
    /**
     * Creates cluster client with single node discovery
     * @param jedisClusterNode Any cluster node endpoint
     */
    public JedisCluster(HostAndPort jedisClusterNode);
    
    /**
     * Creates cluster client with multiple discovery nodes
     * @param clusterNodes Set of cluster node endpoints for discovery
     */
    public JedisCluster(Set<HostAndPort> clusterNodes);
    
    /**
     * Creates cluster client with configuration
     * @param clusterNodes Cluster discovery nodes
     * @param config Client configuration
     */
    public JedisCluster(Set<HostAndPort> clusterNodes, JedisClientConfig config);
    
    /**
     * Creates cluster client with pool configuration
     * @param clusterNodes Cluster discovery nodes
     * @param config Client configuration
     * @param poolConfig Pool configuration for node connections
     */
    public JedisCluster(Set<HostAndPort> clusterNodes, JedisClientConfig config,
                       JedisPoolConfig poolConfig);
    
    /**
     * Creates cluster client with timeout settings
     * @param clusterNodes Cluster discovery nodes
     * @param connectionTimeout Connection timeout in milliseconds
     * @param soTimeout Socket timeout in milliseconds
     */
    public JedisCluster(Set<HostAndPort> clusterNodes, int connectionTimeout, int soTimeout);
    
    /**
     * Creates cluster client with retry settings
     * @param clusterNodes Cluster discovery nodes
     * @param connectionTimeout Connection timeout
     * @param soTimeout Socket timeout
     * @param maxAttempts Maximum retry attempts for commands
     */
    public JedisCluster(Set<HostAndPort> clusterNodes, int connectionTimeout, 
                       int soTimeout, int maxAttempts);
    
    /**
     * Gets connection pool for specific cluster node
     * @param node Cluster node endpoint
     * @return Connection pool for the node
     */
    public JedisPool getConnectionPoolFromSlot(int slot);
    
    /**
     * Gets all cluster node pools
     * @return Map of node endpoints to connection pools
     */
    public Map<String, JedisPool> getClusterNodes();
    
    /**
     * Refreshes cluster topology information
     */
    public void refreshClusterSlots();
    
    /**
     * Gets cluster slot cache
     * @return Current slot-to-node mapping
     */
    public Map<Integer, JedisPool> getSlotPoolMap();
    
    /**
     * Closes cluster client and all node connections
     */
    public void close();
}

Set<HostAndPort> clusterNodes = new HashSet<>();
clusterNodes.add(new HostAndPort("redis-node1.example.com", 7000));
clusterNodes.add(new HostAndPort("redis-node2.example.com", 7001));
clusterNodes.add(new HostAndPort("redis-node3.example.com", 7002));

JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxTotal(20);
poolConfig.setMaxIdle(10);
poolConfig.setTestOnBorrow(true);

JedisClientConfig clientConfig = DefaultJedisClientConfig.builder()
    .connectionTimeoutMillis(2000)
    .socketTimeoutMillis(2000)
    .password("cluster-password")
    .build();

JedisCluster cluster = new JedisCluster(clusterNodes, clientConfig, poolConfig);

try {
    // Use like regular Redis client - clustering is transparent
    cluster.set("user:1000", "John Doe");
    cluster.hset("user:1000:profile", "email", "john@example.com");
    
    // Keys are automatically routed to correct cluster nodes
    String user = cluster.get("user:1000");
    Map<String, String> profile = cluster.hgetAll("user:1000:profile");
    
    // Cluster-specific operations
    String clusterInfo = cluster.clusterInfo();
    String nodes = cluster.clusterNodes();
    
    // Get slot information
    Long slot = cluster.clusterKeySlot("user:1000");
    List<String> keysInSlot = cluster.clusterGetKeysInSlot(slot.intValue(), 10);
    
} finally {
    cluster.close();
}

public class ClusterPipeline implements AutoCloseable {
    /**
     * Creates cluster pipeline
     * @param clusterNodes Cluster node endpoints
     * @param clientConfig Client configuration
     */
    public ClusterPipeline(Set<HostAndPort> clusterNodes, JedisClientConfig clientConfig);
    
    /**
     * Queues SET command
     * @param key Redis key
     * @param value String value
     * @return Response object for the command
     */
    public Response<String> set(String key, String value);
    
    /**
     * Queues GET command
     * @param key Redis key
     * @return Response object for the command
     */
    public Response<String> get(String key);
    
    /**
     * Queues hash operations
     * @param key Hash key
     * @param field Hash field
     * @param value Field value
     * @return Response object for the command
     */
    public Response<Long> hset(String key, String field, String value);
    
    /**
     * Synchronizes all queued commands
     * Sends commands to appropriate cluster nodes and retrieves responses
     */
    public void sync();
    
    /**
     * Synchronizes and returns all responses
     * @return List of command responses
     */
    public List<Object> syncAndReturnAll();
    
    /**
     * Closes the cluster pipeline
     */
    public void close();
}

Set<HostAndPort> clusterNodes = Set.of(
    new HostAndPort("node1", 7000),
    new HostAndPort("node2", 7001),
    new HostAndPort("node3", 7002)
);

try (ClusterPipeline pipeline = new ClusterPipeline(clusterNodes, clientConfig)) {
    // Queue multiple commands - they'll be routed to appropriate nodes
    Response<String> r1 = pipeline.set("key1", "value1");
    Response<String> r2 = pipeline.set("key2", "value2");
    Response<Long> r3 = pipeline.hset("hash1", "field1", "value1");
    
    // Execute all commands
    pipeline.sync();
    
    // Get results
    String result1 = r1.get();  // "OK"
    String result2 = r2.get();  // "OK"
    Long result3 = r3.get();    // 1
}

public class JedisSentinelPool extends Pool<Jedis> {
    /**
     * Creates sentinel pool with default configuration
     * @param masterName Master name in Sentinel configuration
     * @param sentinels Set of Sentinel endpoints ("host:port")
     */
    public JedisSentinelPool(String masterName, Set<String> sentinels);
    
    /**
     * Creates sentinel pool with pool configuration
     * @param masterName Master name in Sentinel configuration
     * @param sentinels Set of Sentinel endpoints
     * @param poolConfig Pool configuration
     */
    public JedisSentinelPool(String masterName, Set<String> sentinels, 
                           JedisPoolConfig poolConfig);
    
    /**
     * Creates sentinel pool with client configuration
     * @param masterName Master name
     * @param sentinels Sentinel endpoints
     * @param clientConfig Client configuration
     */
    public JedisSentinelPool(String masterName, Set<String> sentinels,
                           JedisClientConfig clientConfig);
    
    /**
     * Creates sentinel pool with full configuration
     * @param masterName Master name
     * @param sentinels Sentinel endpoints
     * @param poolConfig Pool configuration
     * @param clientConfig Client configuration
     */
    public JedisSentinelPool(String masterName, Set<String> sentinels,
                           JedisPoolConfig poolConfig, JedisClientConfig clientConfig);
    
    /**
     * Creates sentinel pool with sentinel authentication
     * @param masterName Master name
     * @param sentinels Sentinel endpoints
     * @param poolConfig Pool configuration
     * @param clientConfig Master client configuration  
     * @param sentinelClientConfig Sentinel client configuration
     */
    public JedisSentinelPool(String masterName, Set<String> sentinels,
                           JedisPoolConfig poolConfig, JedisClientConfig clientConfig,
                           JedisClientConfig sentinelClientConfig);
    
    /**
     * Gets current master endpoint
     * @return Current Redis master host and port
     */
    public HostAndPort getCurrentHostMaster();
    
    /**
     * Gets Jedis connection from pool
     * @return Jedis instance connected to current master
     */
    public Jedis getResource();
    
    /**
     * Destroys the sentinel pool
     */
    public void destroy();
}

public interface SentinelCommands {
    /**
     * Get master address by name
     * @param masterName Master name
     * @return Master host and port
     */
    List<String> sentinelGetMasterAddrByName(String masterName);
    
    /**
     * Get master information
     * @param masterName Master name
     * @return Master configuration and status
     */
    List<Map<String, String>> sentinelMasters();
    
    /**
     * Get specific master information
     * @param masterName Master name
     * @return Master details
     */
    Map<String, String> sentinelMaster(String masterName);
    
    /**
     * Get sentinel information about slaves
     * @param masterName Master name
     * @return List of slave configurations
     */
    List<Map<String, String>> sentinelSlaves(String masterName);
    
    /**
     * Get sentinel information about other sentinels
     * @param masterName Master name
     * @return List of sentinel configurations
     */
    List<Map<String, String>> sentinelSentinels(String masterName);
    
    /**
     * Force failover of master
     * @param masterName Master name
     * @return Status code reply
     */
    String sentinelFailover(String masterName);
    
    /**
     * Monitor new master
     * @param masterName Master name
     * @param ip Master IP address
     * @param port Master port
     * @param quorum Quorum for failover decisions
     * @return Status code reply
     */
    String sentinelMonitor(String masterName, String ip, int port, int quorum);
    
    /**
     * Remove master from monitoring
     * @param masterName Master name
     * @return Status code reply
     */
    String sentinelRemove(String masterName);
    
    /**
     * Set master configuration
     * @param masterName Master name
     * @param parameterName Parameter name
     * @param parameterValue Parameter value
     * @return Status code reply
     */
    String sentinelSet(String masterName, String parameterName, String parameterValue);
}

String masterName = "mymaster";
Set<String> sentinels = new HashSet<>();
sentinels.add("sentinel1.example.com:26379");
sentinels.add("sentinel2.example.com:26379");
sentinels.add("sentinel3.example.com:26379");

JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxTotal(20);
poolConfig.setTestOnBorrow(true);

JedisClientConfig masterConfig = DefaultJedisClientConfig.builder()
    .password("redis-password")
    .database(0)
    .build();

JedisClientConfig sentinelConfig = DefaultJedisClientConfig.builder()
    .password("sentinel-password")
    .build();

JedisSentinelPool sentinelPool = new JedisSentinelPool(
    masterName, sentinels, poolConfig, masterConfig, sentinelConfig
);

try {
    // Use pool normally - failover is automatic
    try (Jedis jedis = sentinelPool.getResource()) {
        jedis.set("key", "value");
        String value = jedis.get("key");
    }
    
    // Monitor current master
    HostAndPort currentMaster = sentinelPool.getCurrentHostMaster();
    System.out.println("Current master: " + currentMaster);
    
} finally {
    sentinelPool.destroy();
}

public class MultiClusterClientConfig {
    public static class Builder {
        /**
         * Sets exceptions that trigger fallback to next cluster
         * @param fallbackExceptionList List of exception classes
         * @return Builder instance
         */
        public Builder fallbackExceptionList(List<Class<? extends Exception>> fallbackExceptionList);
        
        /**
         * Sets circuit breaker sliding window size
         * @param circuitBreakerSlidingWindowSize Window size for failure tracking
         * @return Builder instance
         */
        public Builder circuitBreakerSlidingWindowSize(int circuitBreakerSlidingWindowSize);
        
        /**
         * Sets circuit breaker failure rate threshold
         * @param circuitBreakerFailureRateThreshold Failure rate (0.0-1.0) to open circuit
         * @return Builder instance
         */
        public Builder circuitBreakerFailureRateThreshold(float circuitBreakerFailureRateThreshold);
        
        /**
         * Sets minimum calls before circuit breaker evaluation
         * @param circuitBreakerMinimumNumberOfCalls Minimum calls in window
         * @return Builder instance
         */
        public Builder circuitBreakerMinimumNumberOfCalls(int circuitBreakerMinimumNumberOfCalls);
        
        /**
         * Sets circuit breaker wait duration in open state
         * @param circuitBreakerWaitDurationInOpenState Wait duration in milliseconds
         * @return Builder instance
         */
        public Builder circuitBreakerWaitDurationInOpenState(long circuitBreakerWaitDurationInOpenState);
        
        /**
         * Builds multi-cluster configuration
         * @return Configuration instance
         */
        public MultiClusterClientConfig build();
    }
    
    public List<Class<? extends Exception>> getFallbackExceptionList();
    public int getCircuitBreakerSlidingWindowSize();
    public float getCircuitBreakerFailureRateThreshold();
    public int getCircuitBreakerMinimumNumberOfCalls();
    public long getCircuitBreakerWaitDurationInOpenState();
}

public class MultiClusterPooledConnectionProvider implements ConnectionProvider {
    /**
     * Creates multi-cluster connection provider
     * @param clusters List of cluster connection providers in priority order
     * @param multiClusterClientConfig Multi-cluster configuration
     */
    public MultiClusterPooledConnectionProvider(List<ClusterConnectionProvider> clusters,
                                              MultiClusterClientConfig multiClusterClientConfig);
    
    @Override
    public Connection getConnection();
    
    @Override
    public Connection getConnection(CommandArguments commandArguments);
    
    /**
     * Gets active cluster index
     * @return Index of currently active cluster
     */
    public int getActiveMultiClusterIndex();
    
    /**
     * Gets cluster providers
     * @return List of cluster connection providers
     */
    public List<ClusterConnectionProvider> getClusterConnectionProviders();
    
    /**
     * Manually trigger failover to next cluster
     */
    public void incrementActiveMultiClusterIndex();
    
    @Override
    public void close();
}

public class CircuitBreakerFailoverBase {
    /**
     * Creates circuit breaker failover
     * @param connectionProvider Primary connection provider
     * @param config Multi-cluster configuration
     */
    public CircuitBreakerFailoverBase(ConnectionProvider connectionProvider,
                                    MultiClusterClientConfig config);
    
    /**
     * Executes command with circuit breaker protection
     * @param commandObject Command to execute
     * @return Command result
     */
    public <T> T execute(CommandObject<T> commandObject);
    
    /**
     * Gets circuit breaker state
     * @return Current circuit breaker state (CLOSED, OPEN, HALF_OPEN)
     */
    public String getCircuitBreakerState();
    
    /**
     * Gets failure rate
     * @return Current failure rate (0.0-1.0)
     */
    public float getFailureRate();
    
    /**
     * Resets circuit breaker statistics
     */
    public void resetCircuitBreakerStats();
}

// Configure multiple clusters
List<ClusterConnectionProvider> clusters = Arrays.asList(
    // Primary cluster
    new ClusterConnectionProvider(
        Set.of(new HostAndPort("primary-node1", 7000),
               new HostAndPort("primary-node2", 7001)),
        primaryConfig, poolConfig
    ),
    // Fallback cluster
    new ClusterConnectionProvider(
        Set.of(new HostAndPort("fallback-node1", 7000),
               new HostAndPort("fallback-node2", 7001)),
        fallbackConfig, poolConfig
    )
);

// Configure circuit breaker
MultiClusterClientConfig multiConfig = MultiClusterClientConfig.builder()
    .fallbackExceptionList(Arrays.asList(
        JedisConnectionException.class,
        JedisClusterException.class
    ))
    .circuitBreakerFailureRateThreshold(0.5f)  // 50% failure rate
    .circuitBreakerSlidingWindowSize(100)      // 100 call window
    .circuitBreakerMinimumNumberOfCalls(10)    // Min 10 calls
    .circuitBreakerWaitDurationInOpenState(60000)  // 1 minute wait
    .build();

MultiClusterPooledConnectionProvider mcProvider = 
    new MultiClusterPooledConnectionProvider(clusters, multiConfig);

UnifiedJedis multiClusterJedis = new UnifiedJedis(mcProvider);

try {
    // Operations automatically failover if primary cluster fails
    multiClusterJedis.set("key", "value");
    String value = multiClusterJedis.get("key");
    
    // Monitor cluster state
    int activeCluster = mcProvider.getActiveMultiClusterIndex();
    System.out.println("Active cluster: " + activeCluster);
    
} finally {
    multiClusterJedis.close();
}

public class JedisSharding implements JedisCommands, AutoCloseable {
    /**
     * Creates sharding client with default hashing
     * @param shards List of Redis shard information
     */
    public JedisSharding(List<JedisShardInfo> shards);
    
    /**
     * Creates sharding client with custom hashing algorithm
     * @param shards List of Redis shard information
     * @param algo Hashing algorithm implementation
     */
    public JedisSharding(List<JedisShardInfo> shards, Hashing algo);
    
    /**
     * Creates sharding client with key tag pattern
     * @param shards List of Redis shard information  
     * @param keyTagPattern Pattern for extracting hash tags from keys
     */
    public JedisSharding(List<JedisShardInfo> shards, Pattern keyTagPattern);
    
    /**
     * Gets shard information for a key
     * @param key Redis key
     * @return Shard info for the key
     */
    public JedisShardInfo getShardInfo(String key);
    
    /**
     * Gets all shard information
     * @return Collection of all shards
     */
    public Collection<JedisShardInfo> getAllShardInfo();
    
    /**
     * Gets Jedis connection for specific key
     * @param key Redis key
     * @return Jedis instance for the shard containing the key
     */
    public Jedis getShard(String key);
    
    /**
     * Gets Jedis connection for specific shard info
     * @param shardInfo Shard information
     * @return Jedis instance for the shard
     */
    public Jedis getShard(JedisShardInfo shardInfo);
    
    /**
     * Closes all shard connections
     */
    public void close();
}

public class JedisShardInfo {
    /**
     * Creates shard info with equal weight
     * @param host Redis host
     * @param port Redis port
     */
    public JedisShardInfo(String host, int port);
    
    /**
     * Creates shard info with custom weight
     * @param host Redis host
     * @param port Redis port
     * @param weight Shard weight for consistent hashing
     */
    public JedisShardInfo(String host, int port, int weight);
    
    /**
     * Creates shard info with name and weight
     * @param host Redis host
     * @param port Redis port  
     * @param name Shard name
     * @param weight Shard weight
     */
    public JedisShardInfo(String host, int port, String name, int weight);
    
    /**
     * Creates shard info from URI
     * @param uri Redis connection URI
     */
    public JedisShardInfo(URI uri);
    
    public String getHost();
    public int getPort();
    public String getName();
    public int getWeight();
    public int getTimeout();
    public String getPassword();
    
    /**
     * Sets connection timeout
     * @param timeout Timeout in milliseconds
     */
    public void setTimeout(int timeout);
    
    /**
     * Sets authentication password
     * @param auth Redis password
     */
    public void setPassword(String auth);
}

// Create shards with different weights
List<JedisShardInfo> shards = Arrays.asList(
    new JedisShardInfo("redis1.example.com", 6379, "shard1", 1),
    new JedisShardInfo("redis2.example.com", 6379, "shard2", 1), 
    new JedisShardInfo("redis3.example.com", 6379, "shard3", 2)  // Double weight
);

JedisSharding sharding = new JedisSharding(shards);

try {
    // Keys automatically distributed based on consistent hashing
    sharding.set("user:1000", "John");     // Routed to appropriate shard
    sharding.set("user:2000", "Jane");     // May go to different shard
    
    // Retrieve data - client finds correct shard automatically
    String user1 = sharding.get("user:1000");
    String user2 = sharding.get("user:2000");
    
    // Get shard information
    JedisShardInfo shardInfo = sharding.getShardInfo("user:1000");
    System.out.println("Key user:1000 on shard: " + shardInfo.getName());
    
} finally {
    sharding.close();
}

public class JedisBroadcastAndRoundRobinConfig {
    /**
     * Creates broadcast and round robin configuration
     * @param pools List of connection pools for different Redis instances
     */
    public JedisBroadcastAndRoundRobinConfig(List<Pool<Connection>> pools);
    
    /**
     * Gets connection for broadcast operation (all pools)
     * @return List of connections from all pools
     */
    public List<Connection> getBroadcastConnections();
    
    /**
     * Gets connection for round-robin operation (next pool in rotation)
     * @return Connection from next pool in round-robin
     */
    public Connection getRoundRobinConnection();
    
    /**
     * Gets all connection pools
     * @return List of connection pools
     */
    public List<Pool<Connection>> getPools();
}