org.apache.storm.cassandra.bolt

Class BaseCassandraBolt<T>

java.lang.Object

org.apache.storm.topology.base.BaseComponent

org.apache.storm.topology.base.BaseRichBolt

org.apache.storm.topology.base.BaseTickTupleAwareRichBolt

org.apache.storm.cassandra.bolt.BaseCassandraBolt<T>

All Implemented Interfaces:

Serializable, IBolt, IComponent, IRichBolt

Direct Known Subclasses:

BatchCassandraWriterBolt, CassandraWriterBolt

public abstract class BaseCassandraBolt<T>
extends BaseTickTupleAwareRichBolt

A base cassandra bolt.

Default BaseTickTupleAwareRichBolt

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected CassandraConf	cassandraConf
protected SimpleClient	client
protected SimpleClientProvider	clientProvider
protected OutputCollector	outputCollector
protected com.datastax.driver.core.Session	session
protected Map<String,Object>	topoConfig

Constructor Summary

Constructors

Constructor and Description
BaseCassandraBolt(CQLStatementTupleMapper tupleMapper) Creates a new CassandraWriterBolt instance.
BaseCassandraBolt(CQLStatementTupleMapper mapper, SimpleClientProvider clientProvider) Creates a new CassandraWriterBolt instance.

Method Summary

Modifier and Type	Method and Description
void	cleanup() Called when an IBolt is going to be shutdown.
void	declareOutputFields(OutputFieldsDeclarer declarer) Declare the output schema for all the streams of this topology.
void	execute(Tuple input) Process a single tuple of input.
protected AsyncExecutor<T>	getAsyncExecutor()
protected abstract AsyncResultHandler<T>	getAsyncHandler()
Map<String,Object>	getComponentConfiguration() Declare configuration specific to this component.
protected CQLStatementTupleMapper	getMapper()
protected ExecutionResultHandler	getResultHandler()
void	prepare(Map<String,Object> topoConfig, TopologyContext topologyContext, OutputCollector outputCollector) Called when a task for this component is initialized within a worker on the cluster.
BaseCassandraBolt	withCassandraConfig(Map<String,Object> config) Takes the given config for creating cassandra client.
BaseCassandraBolt	withOutputFields(Fields fields) Configures this bolt with the given fields as outputfields with stream id as Utils.DEFAULT_STREAM_ID.
BaseCassandraBolt	withResultHandler(ExecutionResultHandler resultHandler)
BaseCassandraBolt	withStreamOutputFields(String stream, Fields fields) Configures this bolt given fields as outputfields for the given stream.

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

onTickTuple, process

Methods inherited from class java.lang.Object

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

Field Detail

outputCollector

protected OutputCollector outputCollector

clientProvider

protected SimpleClientProvider clientProvider

client

protected SimpleClient client

session

protected com.datastax.driver.core.Session session

topoConfig

protected Map<String,Object> topoConfig

cassandraConf

protected CassandraConf cassandraConf

Constructor Detail

BaseCassandraBolt

public BaseCassandraBolt(CQLStatementTupleMapper mapper,
                         SimpleClientProvider clientProvider)

Creates a new CassandraWriterBolt instance.

BaseCassandraBolt

public BaseCassandraBolt(CQLStatementTupleMapper tupleMapper)

Creates a new CassandraWriterBolt instance.

Method Detail

prepare

public void prepare(Map<String,Object> topoConfig,
                    TopologyContext topologyContext,
                    OutputCollector outputCollector)

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:

topoConfig - 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.

outputCollector - 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.

withResultHandler

public BaseCassandraBolt withResultHandler(ExecutionResultHandler resultHandler)

withOutputFields

public BaseCassandraBolt withOutputFields(Fields fields)

Configures this bolt with the given fields as outputfields with stream id as Utils.DEFAULT_STREAM_ID.

Parameters:

fields - outputfields

withStreamOutputFields

public BaseCassandraBolt withStreamOutputFields(String stream,
                                                Fields fields)

Configures this bolt given fields as outputfields for the given stream.

withCassandraConfig

public BaseCassandraBolt withCassandraConfig(Map<String,Object> config)

Takes the given config for creating cassandra client. CassandraConf contains all the properties that can be configured.

getResultHandler

protected ExecutionResultHandler getResultHandler()

getMapper

protected CQLStatementTupleMapper getMapper()

getAsyncHandler

protected abstract AsyncResultHandler<T> getAsyncHandler()

getAsyncExecutor

protected AsyncExecutor<T> getAsyncExecutor()

execute

public final void execute(Tuple input)

Process a single tuple of input. The Tuple object contains metadata on it about which component/stream/task it came from. The values of the Tuple can be accessed using Tuple#getValue. The IBolt does not have to process the Tuple immediately. It is perfectly fine to hang onto a tuple and process it later (for instance, to do an aggregation or join).

Tuples should be emitted using the OutputCollector provided through the prepare method. It is required that all input tuples are acked or failed at some point using the OutputCollector. Otherwise, Storm will be unable to determine when tuples coming off the spouts have been completed.

For the common case of acking an input tuple at the end of the execute method, see IBasicBolt which automates this.

Specified by:

execute in interface IBolt

Overrides:

execute in class BaseTickTupleAwareRichBolt

Parameters:

input - the tuple to process.

declareOutputFields

public void declareOutputFields(OutputFieldsDeclarer declarer)

Declare the output schema for all the streams of this topology.

Parameters:

declarer - this is used to declare output stream ids, output fields, and whether or not each output stream is a direct stream

getComponentConfiguration

public Map<String,Object> getComponentConfiguration()

Declare configuration specific to this component. Only a subset of the “topology.*” configs can be overridden. The component configuration can be further overridden when constructing the topology using TopologyBuilder

Specified by:

getComponentConfiguration in interface IComponent

Overrides:

getComponentConfiguration in class BaseComponent

cleanup

public void cleanup()

Called when an IBolt is going to be shutdown. Storm will make a best-effort attempt to call this if the worker shutdown is orderly. The Config.SUPERVISOR_WORKER_SHUTDOWN_SLEEP_SECS setting controls how long orderly shutdown is allowed to take. There is no guarantee that cleanup will be called if shutdown is not orderly, or if the shutdown exceeds the time limit.

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