This document is intended for helping you migrate your Apache Camel applications from version 2.x to 3.0.
// TODO when we drop Java8 // TODO Apache Camel 3 requires Java 11. Java 8 are no longer supported.
One of the biggest change is the modularization of camel-core. In Camel 2.x camel-core was one JAR file, which now has been splitup into many JARs as follows:
- camel-api
- camel-base
- camel-core
- camel-management-api
- camel-management-impl
- camel-support
- camel-util
Maven users of Apache Camel can keep using the dependency camel-core which will have transitive dependency on all of its modules, and therefore no migration is needed. However users whom wants to trim the size of the classes on the classpath, can use fine grained Maven dependency on only the modules needed. You may find how to do that in the examples.
We have also modularized many of the core components and moved them out of camel-core to individual components:
- camel-browse
- camel-controlbus
- camel-dataformat
- camel-direct
- camel-directvm
- camel-file
- camel-language
- camel-log
- camel-properties
- camel-ref
- camel-rest
- camel-saga
- camel-scheduler
- camel-seda
- camel-stub
- camel-timer
- camel-validator
- camel-xslt
TODO: there are some remainder components in camel-core we would like to modularize TODO: we need camel-core-minimal dependency for just basic Camel
You should depend on camel-support and not camel-core directly.
The classes from org.apache.camel.impl that was intended to support Camel developers building custom components has been moved out of camel-core into camel-support into the org.apache.camel.support package. For example classes such as DefaultComponent, DefaultEndpoint etc has been moved and migration is nessasary.
// TODO: Should we create a camel2-support JAR with an adapter to bridge between 2.x and 3.0
All deprecated APIs and components from Camel 2.x has been removed in Camel 3.
We have removed all deprecated components from Camel 2.x, also including the old camel-http component. Instead you can use camel-http4.
We have also renamed camel-jetty9 to camel-jetty.
If you are using the activemq-camel component, then you should migrate to use camel-activemq component, where the component name has changed from org.apache.activemq.camel.component.ActiveMQComponent to org.apache.camel.component.activemq.ActiveMQComponent.
If you run Camel standalone with just camel-core as dependency, and you want JMX enabled out of the box, then you need to add camel-management-impl as dependency.
For using ManagedCamelContext you now need to get this an extension from CamelContext as follows:
ManagedCamelContext managed = camelContext.getExtension(ManagedCamelContext.class);
In Camel 2.x we have deprecated getProperties on CamelContext in favour of getGlobalOptions, so you should migrate to:
context.getGlobalOptions().put("CamelJacksonEnableTypeConverter", "true");
context.getGlobalOptions().put("CamelJacksonTypeConverterToPojo", "true");
... and in XML:
<globalOptions>
<globalOption key="CamelJacksonEnableTypeConverter" value="true"/>
<globalOption key="CamelJacksonTypeConverterToPojo" value="true"/>
</globalOptions>
The following API changes may affect your existing Camel applications, which needs to be migrated.
TODO: Should this be a table? TODO: Add the other moved classes/packages etc
The classes from org.apache.camel.impl that was intended to support Camel developers building custom components has been moved out of camel-core into camel-support into the org.apache.camel.support package. If you have built custom Camel components that may have used some of these APIs you would then need to migrate.
All the classes in org.apache.camel.util.component has been moved from the camel-core JAR to the package org.apache.camel.support.component in the camel-support JAR.
The method xslt has been removed from org.apache.camel.builder.AggregationStrategies. Instead use the XsltAggregationStrategy from camel-xslt JAR directly.
The getter/setter for bindingMode on RestEndpoint has been changed to use type org.apache.camel.spi.RestConfiguration.RestBindingMode from camel-api JAR. Instead of using this type class you can also call the setter method with string type instead.
The activemq-camel component has been moved from ActiveMQ into Camel and it is now called camel-activemq, the package has been changed accordingly to org.apache.camel.component.activemq
The method includeRoutes on RouteBuilder has been removed. This functionality was not fully in use and was deprecated in Camel 2.x.
The exception PredicateValidationException has been moved from package org.apache.camel.processor.validation to org.apache.camel.support.processor.validation.PredicateValidationException.
The class org.apache.camel.util.toolbox.AggregationStrategies has been moved to org.apache.camel.builder.AggregationStrategies.
The class org.apache.camel.processor.aggregate.AggregationStrategy has been moved to org.apache.camel.AggregationStrategy.
The class org.apache.camel.processor.loadbalancer.SimpleLoadBalancerSupport has been removed, instead use org.apache.camel.processor.loadbalancer.LoadBalancerSupport.
The startRoute, stopRoute, suspendRoute, resumeRoute, getRouteStatus, and other related methods on CamelContext has been moved to the RouteController as shown below:
context.getRouteController().startRoute("myRoute");
All the events from package org.apache.camel.management.event has been moved to the class org.apache.camel.spi.CamelEvent as sub-classes, for example the event for CamelContext started would be CamelEvent.CamelContextStartedEvent.
Testing using adviceWith currently needs to be changed from:
context.getRouteDefinition("start").adviceWith(context, new RouteBuilder() {
...
}
to using style:
RouteReifier.adviceWith(context.getRouteDefinition("start"), context, new RouteBuilder() {
...
}
We are planning on making this easier in 3.0.0-M2 onwards.
The class JNDIContext has been moved from org.apache.camel.util.jndi.JNDIContext in the camel-core JAR to org.apache.camel.support.jndi.JNDIContext and moved to the camel-support JAR.
The circuitBreaker load-balancer EIP was deprecated in Camel 2.x, and has been removed. Instead use Hystrix EIP as the load-balancer.
The class ThreadPoolRejectedPolicy has been moved from org.apache.camel.ThreadPoolRejectedPolicy to org.apache.camel.util.concurrent.ThreadPoolRejectedPolicy.
The simple language property function was deprecated in Camel 2.x and has been removed. Use exchangeProperty as function name.
The terser language has been renamed from terser to hl7terser.
The classes from org.apache.camel.util.jsse has been moved to org.apache.camel.support.jsse.
The class AsyncProcessorHelper has been moved from org.apache.camel.util.AsyncProcessorHelper in the camel-core JAR to org.apache.camel.support.AsyncProcessorHelper and moved to the camel-support JAR.
The class AsyncProcessorConverterHelper has been moved from org.apache.camel.util.AsyncProcessorConverterHelper in the camel-core JAR to org.apache.camel.support.AsyncProcessorConverterHelper and moved to the camel-support JAR.
The class CamelContextHelper has been moved from org.apache.camel.util.CamelContextHelper in the camel-core JAR to org.apache.camel.support.CamelContextHelper and moved to the camel-support JAR.
The class EndpointHelper has been moved from org.apache.camel.util.EndpointHelper in the camel-core JAR to org.apache.camel.support.EndpointHelper and moved to the camel-support JAR.
The class EventHelper has been moved from org.apache.camel.util.EventHelper in the camel-core JAR to org.apache.camel.support.EventHelper and moved to the camel-support JAR.
The class ExchangeHelper has been moved from org.apache.camel.util.ExchangeHelper in the camel-core JAR to org.apache.camel.support.ExchangeHelper and moved to the camel-support JAR.
The class GZIPHelper has been moved from org.apache.camel.util.GZIPHelper in the camel-core JAR to org.apache.camel.support.GZIPHelper and moved to the camel-support JAR.
The class JsonSchemaHelper has been moved from org.apache.camel.util.JsonSchemaHelper in the camel-core JAR to org.apache.camel.support.JsonSchemaHelper and moved to the camel-support JAR.
The class MessageHelper has been moved from org.apache.camel.util.MessageHelper in the camel-core JAR to org.apache.camel.support.MessageHelper and moved to the camel-support JAR.
The class ObjectHelper has been moved from org.apache.camel.util.ObjectHelper in the camel-core JAR and splitted into org.apache.camel.support.ObjectHelper and moved to the camel-support JAR and into org.apache.camel.util.ObjectHelper and moved to the camel-util JAR. This has been done to isolate the methods using camel-api JAR: those method are in the camel-support JAR, the other in the camel-util JAR.
The class PlatformHelper has been moved from org.apache.camel.util.PlatformHelper in the camel-core JAR to org.apache.camel.support.PlatformHelper and moved to the camel-support JAR.
The class PredicateAssertHelper has been moved from org.apache.camel.util.PredicateAssertHelper in the camel-core JAR to org.apache.camel.support.PredicateAssertHelper and moved to the camel-support JAR.
The class ResolverHelper has been moved from org.apache.camel.util.ResolverHelper in the camel-core JAR to org.apache.camel.support.ResolverHelper and moved to the camel-support JAR.
The class ResourceHelper has been moved from org.apache.camel.util.ResourceHelper in the camel-core JAR to org.apache.camel.support.ResourceHelper and moved to the camel-support JAR.
The class RestProducerFactoryHelper has been moved from org.apache.camel.spi.RestProducerFactoryHelper in the camel-core JAR to org.apache.camel.support.RestProducerFactoryHelper and moved to the camel-support JAR.
The class ServiceHelper has been moved from org.apache.camel.util.ServiceHelper in the camel-core JAR to org.apache.camel.support.service.ServiceHelper and moved to the camel-api JAR.
The class UnitOfWorkHelper has been moved from org.apache.camel.util.UnitOfWorkHelper in the camel-core JAR to org.apache.camel.support.UnitOfWorkHelper and moved to the camel-support JAR.
The class FileIdempotentRepository has been moved from org.apache.camel.processor.idempotent.FileIdempotentRepository in the camel-core JAR to org.apache.camel.support.processor.idempotent.FileIdempotentRepository and moved to the camel-suppor JAR.
The class MemoryIdempotentRepository has been moved from org.apache.camel.processor.idempotent.MemoryIdempotentRepository in the camel-core JAR to org.apache.camel.support.processor.idempotent.MemoryIdempotentRepository and moved to the camel-suppor JAR.
The class org.apache.camel.impl.RoutePolicySupport has been moved to org.apache.camel.support.RoutePolicySupport.
The class org.apache.camel.impl.ThrottlingInflightRoutePolicy has been moved to org.apache.camel.throttling.ThrottlingInflightRoutePolicy
The class XsltAggregationStrategy has been moved from org.apache.camel.builder.XsltAggregationStrategy in the camel-core JAR to org.apache.camel.component.xslt.XsltAggregationStrategy and moved to the camel-xslt JAR.
When using the option groupedExchange on the aggregator EIP then the output of the aggregation is now longer also stored in the exchange property Exchange.GROUPED_EXCHANGE. This behaviour was already deprecated from Camel 2.13 onwards.
The default for use breadcrumbs has been changed from true to false.
The XML DSL has been changed slightly.
The custom load balancer EIP has changed from <custom> to <customLoadBalancer>
The XMLSecurity data format has renamed the attribute keyOrTrustStoreParametersId to keyOrTrustStoreParametersRef in the <secureXML> tag.
The <zipFile> data format has been renamed to <zipfile>.
The camel-maven-plugin has been splitup into two maven plugins:
- camel-maven-plugin
- camel-report-maven-plugin
The former has the run goal, which is intended for quickly running Camel applications standalone.
The camel-report-maven-plugin has the validate and route-coverage goals which is used for generating reports of your Camel projects such as validating Camel endpoint URIs and route coverage reports, etc.
There is an issue with MDC logging and correctly transfering the Camel breadscrumb id's under certain situations with routing over asynchronous endpoints, due to the internal routing engine refactorings. This change also affects the camel-zipkin component, with may not correctly transfer the span id's when using MDC logging as well.
The tracer feature does not work (the implementation from Camel 2.x was deprecated), and we plan to implemented a new and improved tracer.