org.springframework.kafka.listener.adapter

Class AbstractAdaptableMessageListener<K,V>

java.lang.Object

org.springframework.kafka.listener.adapter.AbstractAdaptableMessageListener<K,V>

Type Parameters:

K - the key type.

V - the value type.

All Implemented Interfaces:

AcknowledgingMessageListener<K,V>, MessageListener<K,V>

Direct Known Subclasses:

MessagingMessageListenerAdapter

public abstract class AbstractAdaptableMessageListener<K,V>
extends java.lang.Object
implements MessageListener<K,V>, AcknowledgingMessageListener<K,V>

An abstract MessageListener adapter providing the necessary infrastructure to extract the payload of a Message.

Author:

Stephane Nicoll, Gary Russell

See Also:

MessageListener, AcknowledgingMessageListener

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.commons.logging.Log	logger

Constructor Summary

Constructors

Constructor and Description
AbstractAdaptableMessageListener()

Method Summary

Modifier and Type	Method and Description
protected java.lang.Object	extractMessage(org.apache.kafka.clients.consumer.ConsumerRecord<K,V> record) Extract the message body from the given Kafka message.
protected void	handleListenerException(java.lang.Throwable ex) Handle the given exception that arose during listener execution.
void	onMessage(org.apache.kafka.clients.consumer.ConsumerRecord<K,V> record) Kafka MessageListener entry point.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.kafka.listener.AcknowledgingMessageListener

onMessage

Field Detail

logger

protected final org.apache.commons.logging.Log logger

Constructor Detail

AbstractAdaptableMessageListener

public AbstractAdaptableMessageListener()

Method Detail

onMessage

public void onMessage(org.apache.kafka.clients.consumer.ConsumerRecord<K,V> record)

Kafka MessageListener entry point.

Delegate the message to the target listener method, with appropriate conversion of the message argument. In case of an exception, the handleListenerException(Throwable) method will be invoked.

Specified by:

onMessage in interface MessageListener<K,V>

Parameters:

record - the incoming Kafka ConsumerRecord.

See Also:

handleListenerException(java.lang.Throwable), AcknowledgingMessageListener.onMessage(ConsumerRecord, org.springframework.kafka.support.Acknowledgment)

handleListenerException

protected void handleListenerException(java.lang.Throwable ex)

Handle the given exception that arose during listener execution. The default implementation logs the exception at error level.

This method only applies when using a Kafka MessageListener. With AcknowledgingMessageListener, exceptions get handled by the caller instead.

Parameters:

ex - the exception to handle

See Also:

onMessage(ConsumerRecord)

extractMessage

protected java.lang.Object extractMessage(org.apache.kafka.clients.consumer.ConsumerRecord<K,V> record)

Extract the message body from the given Kafka message.

Parameters:

record - the Kafka Message

Returns:

the content of the message, to be passed into the listener method as argument