camel custom marshalling with dataFormat name in header - apache

Question

I'm having two routes in two separated projects :
First route is setting the header with a data format bean name as a constant :
setHeader("dataFormatBeanName", constant("myFirstList"))
First route :
public class MyTest {
#Configuration
public static class MyTestConfig extends CamelConfiguration {
#Bean(name = "myFirstList")
public DataFormat getMyFirstListDataFormat() {
return new MyFirstListDataFormat();
}
#Bean(name = "mySecondList")
public DataFormat getMySecondListDataFormat() {
return new MySecondListDataFormat();
}
#Bean
public RouteBuilder route() {
return new RouteBuilder() {
#Override
public void configure() throws Exception {
from("direct:testFirstDataFormat").setHeader("dataFormatBeanName", constant("myFirstList")).to("direct:myRoute");
from("direct:testSecondDataFormat").setHeader("dataFormatBeanName", constant("mySecondList")).to("direct:myRoute");
}
};
}
}
}
Second route is supposed to retrieve the bean name from the header and use it as a custom marshaller. Something like :
custom(header("dataFormatBeanName"))
(doesn't compile)
Anyone knows how I'm supposed to get my bean name from the header to use it in the custom method ?
#Component
public class MyRouteBuilder extends RouteBuilder {
#Override
public void configure() throws Exception {
final RouteDefinition routedefinition = this.from("direct:myRoute");
routedefinition.marshal().custom(??????????).to("netty4:tcp://{{route.address}}:{{port}}?textline=true&sync=true");
}

Answer 1

After a few more hours searching, here is the solution a found :
No changes in the first class.
Second class uses an anonymous DataFormat in which I retrieve the bean name from the header and get the spring bean from camel context before calling its marshal method.
The AbstractXxxDataFormat class belongs to project2 and is inherited by the Project1 DataFormat.
#Override
public void configure() throws Exception {
final RouteDefinition routedefinition = this.from("direct:myRoute");
routedefinition.marshal(new DataFormat() {
#Override
public void marshal(final Exchange exchange, final Object graph, final OutputStream stream) throws Exception {
AbstractXxxDataFormat myDataFormat = (AbstractGoalDataFormat) getContext().getRegistry().lookupByName(exchange.getIn().getHeader("dataFormatBeanName", String.class));
myDataFormat.marshal(exchange, graph, stream);
}
#Override
public Object unmarshal(final Exchange exchange, final InputStream stream) throws Exception {
return null;
}
});
routedefinition.to("netty4:tcp://{{route.address}}:{{port}}?textline=true&sync=true");
}
If there's any better solution available, I'll be interested.

Answer 2

Have you tried simple("${header.dataFormatBeanName}") to access the header?
Also, rather than passing the format bean name in a header in the first place, why not factor out each .marshal() call into two subroutes (one for formatBeanA and one for formatBeanB) and then call the appropriate subroute rather than setting the header in the first place? I believe this could be a cleaner approach.

Answer 3

If you really need to get it in the route as a variable (as opposed to a predicate to be used in the builder api) you could use an inline processor to extract it:
public class MyRouteBuilder extends RouteBuilder {
public void configure() throws Exception {
from("someEndpoint")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
String beanName = exchange.getHeader("beanNameHeader");
}
});
}
}
Just be careful of scope and concurrency when storing the extracted beanName however.

Answer 4

A collegue of mine (thanks to him) found the definite solution :
set bean name in the exchange properties :
exchange.setProperty("myDataFormat", "myDataFormatAutowiredBean");
retrieve the dataFormat bean with RecipientList pattern and (un)marshal :
routedefinition.recipientList(simple("dataformat:${property.myDataFormat}:marshal"));
routedefinition.recipientList(simple("dataformat:${property.myDataFormat}:unmarshal"));
Very concise and works just fine.