custom converter to string (json, xml, csv)

I have a custom object that I will be passing through Camel routes and
there may be times where I want to convert the object to different formats,
which means that I need to write custom converters. My question is, how do
I write a converter for the different String-based formats such as JSON,
XML and CSV and have Camel be smart enough to choose the correct one?

If I have the following methods

@Converter
public String myObjectToXml( MyObject event ){
// do stuff here
return "<xml>junk</xml>";

@Converter
public String myObjectToJson( MyObject event ){
// do stuff here
return "{stuff:junk}";

@Converter
public String myObjectToCsv( MyObject event ){
// do stuff here
return "junk,blah";

So I would marshal the object to a String-based format, but how does Camel
know which one I want?