Class FromCloudEventTransformer

java.lang.Object

org.springframework.integration.context.IntegrationObjectSupport

org.springframework.integration.transformer.AbstractTransformer

org.springframework.integration.cloudevents.transformer.FromCloudEventTransformer

All Implemented Interfaces:

Aware, BeanFactoryAware, BeanNameAware, InitializingBean, ApplicationContextAware, ComponentSourceAware, ExpressionCapable, GenericTransformer<Message<?>, Message<?>>, NamedComponent, Transformer

public class FromCloudEventTransformer
extends AbstractTransformer

Transform CloudEvent format messages to Spring Integration messages.

This transformer supports two payload types:

• CloudEvent Object Type: When the message payload is a CloudEvent instance, the transformer extracts the CloudEvent data from the message payload and maps CloudEvent attributes to message headers using CloudEventHeaders constants. CloudEvent extensions are also mapped to message headers with the "ce-" prefix.
• Serialized CloudEvent Type: When the message payload is a byte[] containing a serialized CloudEvent (e.g., JSON, XML), the transformer uses the MessageHeaders.CONTENT_TYPE header to resolve an EventFormat via EventFormatProvider. If the EventFormat is not found from the MessageHeaders.CONTENT_TYPE or if the message does not contain MessageHeaders.CONTENT_TYPE then it will fall back to the setEventFormat(EventFormat). The CloudEvent is then deserialized, and the data is extracted from the CloudEvent with its attributes mapped to headers.

Since:

7.1

Author:

Glenn Renfro, Artem Bilan

See Also:

• ToCloudEventTransformer
• CloudEventHeaders
• CloudEvent
• EventFormat

Field Summary

Fields inherited from class org.springframework.integration.context.IntegrationObjectSupport

EXPRESSION_PARSER, logger

Constructor Summary

Constructors

Constructor	Description
FromCloudEventTransformer()

Method Summary

Modifier and Type	Method	Description
protected Object	doTransform(Message<?> message)	Subclasses must implement this method to provide the transformation logic.
String	getComponentType()
void	setEventFormat(io.cloudevents.core.format.EventFormat eventFormat)	Establish the EventFormat that will be used if the EventFormatProvider can not identify the EventFormat for the MessageHeaders.CONTENT_TYPE or the message does not contain a MessageHeaders.CONTENT_TYPE.

Methods inherited from class org.springframework.integration.transformer.AbstractTransformer

transform

Methods inherited from class org.springframework.integration.context.IntegrationObjectSupport

afterPropertiesSet, extractTypeIfPossible, generateId, getApplicationContext, getApplicationContextId, getBeanDescription, getBeanFactory, getBeanName, getChannelResolver, getComponentDescription, getComponentName, getComponentSource, getConversionService, getExpression, getIntegrationProperties, getMessageBuilderFactory, getTaskScheduler, isInitialized, onInit, setApplicationContext, setBeanFactory, setBeanName, setChannelResolver, setComponentDescription, setComponentName, setComponentSource, setConversionService, setMessageBuilderFactory, setPrimaryExpression, setTaskScheduler, toString

Methods inherited from class java.lang.Object

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

Constructor Details

FromCloudEventTransformer

public FromCloudEventTransformer()

Method Details

setEventFormat

public void setEventFormat(io.cloudevents.core.format.EventFormat eventFormat)

Establish the EventFormat that will be used if the EventFormatProvider can not identify the EventFormat for the MessageHeaders.CONTENT_TYPE or the message does not contain a MessageHeaders.CONTENT_TYPE.

Parameters:

eventFormat - The fallback EventFormat to use if EventFormatProvider can not identify the EventFormat for the payload.

getComponentType

public String getComponentType()

doTransform

protected Object doTransform(Message<?> message)

Description copied from class: AbstractTransformer

Subclasses must implement this method to provide the transformation logic. If the return value is itself a Message, it will be used as the result. Otherwise, any non-null return value will be used as the payload of the result Message.

Specified by:

doTransform in class AbstractTransformer

Parameters:

message - The message.

Returns:

The result of the transformation.