org.apache.storm.jms.spout

Class JmsSpout

java.lang.Object

org.apache.storm.topology.base.BaseComponent

org.apache.storm.topology.base.BaseRichSpout

org.apache.storm.jms.spout.JmsSpout

All Implemented Interfaces:

Serializable, javax.jms.MessageListener, ISpout, IComponent, IRichSpout

public class JmsSpout
extends BaseRichSpout
implements javax.jms.MessageListener

A Storm Spout implementation that listens to a JMS topic or queue and outputs tuples based on the messages it receives.

JmsSpout instances rely on JmsProducer implementations to obtain the JMS ConnectionFactory and Destination objects necessary to connect to a JMS topic/queue.

When a JmsSpout receives a JMS message, it delegates to an internal JmsTupleProducer instance to create a Storm tuple from the incoming message.

Typically, developers will supply a custom JmsTupleProducer implementation appropriate for the expected message content.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
Serializable	recoveryMutex

Constructor Summary

Constructors

Constructor and Description
JmsSpout()

Method Summary

Modifier and Type	Method and Description
void	ack(Object msgId)
void	close()
void	declareOutputFields(OutputFieldsDeclarer declarer)
void	fail(Object msgId)
int	getJmsAcknowledgeMode() Returns the JMS Session acknowledgement mode for the JMS seesion associated with this spout.
protected javax.jms.Session	getSession()
boolean	hasFailures() Returns true if the spout has received failures from which it has not yet recovered.
boolean	isDistributed()
void	nextTuple()
void	onMessage(javax.jms.Message msg) javax.jms.MessageListener implementation.
void	open(Map conf, TopologyContext context, SpoutOutputCollector collector) ISpout implementation.
protected void	recovered()
void	setDistributed(boolean distributed) Sets the “distributed” mode of this spout.
void	setJmsAcknowledgeMode(int mode) Sets the JMS Session acknowledgement mode for the JMS seesion associated with this spout.
void	setJmsProvider(JmsProvider provider) Set the JmsProvider implementation that this Spout will use to connect to a JMS javax.jms.Desination
void	setJmsTupleProducer(JmsTupleProducer producer) Set the JmsTupleProducer implementation that will convert javax.jms.Message object to org.apache.storm.tuple.Values objects to be emitted.
void	setRecoveryPeriod(long period) Sets the periodicity of the timer task that checks for failures and recovers the JMS session.

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

activate, deactivate

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

getComponentConfiguration

Field Detail

recoveryMutex

public final Serializable recoveryMutex

Constructor Detail

JmsSpout

public JmsSpout()

Method Detail

setJmsAcknowledgeMode

public void setJmsAcknowledgeMode(int mode)

Sets the JMS Session acknowledgement mode for the JMS seesion associated with this spout.

Possible values:

• javax.jms.Session.AUTO_ACKNOWLEDGE
• javax.jms.Session.CLIENT_ACKNOWLEDGE
• javax.jms.Session.DUPS_OK_ACKNOWLEDGE

Parameters:

mode - JMS Session Acknowledgement mode

Throws:

IllegalArgumentException - if the mode is not recognized.

getJmsAcknowledgeMode

public int getJmsAcknowledgeMode()

Returns the JMS Session acknowledgement mode for the JMS seesion associated with this spout.

Returns:

setJmsProvider

public void setJmsProvider(JmsProvider provider)

Set the JmsProvider implementation that this Spout will use to connect to a JMS javax.jms.Desination

Parameters:

provider -

setJmsTupleProducer

public void setJmsTupleProducer(JmsTupleProducer producer)

Set the JmsTupleProducer implementation that will convert javax.jms.Message object to org.apache.storm.tuple.Values objects to be emitted.

Parameters:

producer -

onMessage

public void onMessage(javax.jms.Message msg)

javax.jms.MessageListener implementation.

Stored the JMS message in an internal queue for processing by the nextTuple() method.

Specified by:

onMessage in interface javax.jms.MessageListener

open

public void open(Map conf,
                 TopologyContext context,
                 SpoutOutputCollector collector)

ISpout implementation.

Connects the JMS spout to the configured JMS destination topic/queue.

Specified by:

open in interface ISpout

close

public void close()

Specified by:

close in interface ISpout

Overrides:

close in class BaseRichSpout

nextTuple

public void nextTuple()

Specified by:

nextTuple in interface ISpout

ack

public void ack(Object msgId)

Specified by:

ack in interface ISpout

Overrides:

ack in class BaseRichSpout

fail

public void fail(Object msgId)

Specified by:

fail in interface ISpout

Overrides:

fail in class BaseRichSpout

declareOutputFields

public void declareOutputFields(OutputFieldsDeclarer declarer)

Specified by:

declareOutputFields in interface IComponent

hasFailures

public boolean hasFailures()

Returns true if the spout has received failures from which it has not yet recovered.

recovered

protected void recovered()

setRecoveryPeriod

public void setRecoveryPeriod(long period)

Sets the periodicity of the timer task that checks for failures and recovers the JMS session.

Parameters:

period -

isDistributed

public boolean isDistributed()

setDistributed

public void setDistributed(boolean distributed)

Sets the “distributed” mode of this spout.

If true multiple instances of this spout may be created across the cluster (depending on the “parallelism_hint” in the topology configuration).

Setting this value to false essentially means this spout will run as a singleton within the cluster (“parallelism_hint” will be ignored).

In general, this should be set to false if the underlying JMS destination is a topic, and true if it is a JMS queue.

Parameters:

distributed -

getSession

protected javax.jms.Session getSession()