org.apache.storm.redis.bolt

Class AbstractRedisBolt

java.lang.Object

org.apache.storm.topology.base.BaseComponent

org.apache.storm.topology.base.BaseRichBolt

org.apache.storm.topology.base.BaseTickTupleAwareRichBolt

org.apache.storm.redis.bolt.AbstractRedisBolt

All Implemented Interfaces:

Serializable, IBolt, IComponent, IRichBolt

Direct Known Subclasses:

RedisFilterBolt, RedisLookupBolt, RedisStoreBolt

public abstract class AbstractRedisBolt
extends BaseTickTupleAwareRichBolt

AbstractRedisBolt class is for users to implement custom bolts which makes interaction with Redis.

Due to environment abstraction, AbstractRedisBolt provides JedisCommands which contains only single key operations.

Custom Bolts may want to follow this pattern:

 JedisCommands jedisCommands = null; try {  jedisCommand = getInstance();  // do some works } finally {  if (jedisCommand != null) {  returnInstance(jedisCommand);  } } 

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected OutputCollector	collector

Constructor Summary

Constructors

Constructor and Description
AbstractRedisBolt(JedisClusterConfig config) Constructor for Redis Cluster environment (JedisCluster)
AbstractRedisBolt(JedisPoolConfig config) Constructor for single Redis environment (JedisPool)

Method Summary

Modifier and Type	Method and Description
void	cleanup() Called when an IBolt is going to be shutdown.
protected redis.clients.jedis.JedisCommands	getInstance() Borrow JedisCommands instance from container. JedisCommands is an interface which contains single key operations.
void	prepare(Map map, TopologyContext topologyContext, OutputCollector collector) Called when a task for this component is initialized within a worker on the cluster.
protected void	returnInstance(redis.clients.jedis.JedisCommands instance) Return borrowed instance to container.

Methods inherited from class org.apache.storm.topology.base.BaseTickTupleAwareRichBolt

execute, onTickTuple, process

Methods inherited from class org.apache.storm.topology.base.BaseComponent

getComponentConfiguration

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.storm.topology.IComponent

declareOutputFields, getComponentConfiguration

Field Detail

collector

protected OutputCollector collector

Constructor Detail

AbstractRedisBolt

public AbstractRedisBolt(JedisPoolConfig config)

Constructor for single Redis environment (JedisPool)

Parameters:

config - configuration for initializing JedisPool

AbstractRedisBolt

public AbstractRedisBolt(JedisClusterConfig config)

Constructor for Redis Cluster environment (JedisCluster)

Parameters:

config - configuration for initializing JedisCluster

Method Detail

prepare

public void prepare(Map map,
                    TopologyContext topologyContext,
                    OutputCollector collector)

Called when a task for this component is initialized within a worker on the cluster. It provides the bolt with the environment in which the bolt executes.

This includes the:

Parameters:

map - The Storm configuration for this bolt. This is the configuration provided to the topology merged in with cluster configuration on this machine.

topologyContext - This object can be used to get information about this task’s place within the topology, including the task id and component id of this task, input and output information, etc.

collector - The collector is used to emit tuples from this bolt. Tuples can be emitted at any time, including the prepare and cleanup methods. The collector is thread-safe and should be saved as an instance variable of this bolt object.

getInstance

protected redis.clients.jedis.JedisCommands getInstance()

Borrow JedisCommands instance from container.

JedisCommands is an interface which contains single key operations.

Returns:

implementation of JedisCommands

See Also:

JedisCommandsInstanceContainer.getInstance()

returnInstance

protected void returnInstance(redis.clients.jedis.JedisCommands instance)

Return borrowed instance to container.

Parameters:

instance - borrowed object

cleanup

public void cleanup()

Description copied from interface: IBolt

Called when an IBolt is going to be shutdown. There is no guarentee that cleanup will be called, because the supervisor kill -9’s worker processes on the cluster.

The one context where cleanup is guaranteed to be called is when a topology is killed when running Storm in local mode.

Specified by:

cleanup in interface IBolt

Overrides:

cleanup in class BaseRichBolt