组件的Apache Camel默认数据格式

Question

How to set default data format for a component in Apache Camel?

I have a number of routes interacting with different ActiveMQ queues. At the moment all of them look like

from("...")
    .process(...)
    .marshal().json() // (1)
    .to("activemq:queue:...");

or

from("activemq:queue:...")
    .unmarshal().json() // (2)
    .process(...)
    .to("...");

1. I would like to replace lines (1) and (2) with either component or context level configuration. Basically saying only once 'message payload going through ActiveMQ has to be a JSON string'.
2. I don't like to add any additional routes, processors, headers, URI parameters, etc.
3. Ideally, it would be applicable for other components and formats besides ActiveMQ and JSON

Answer 1

You could marshall/unmarshall using a named reference to a data format that you can define once (here as "myDefaultFormat") in your Camel Registry:

from("activemq:queue:...")
.unmarshal(myDefaultFormat)

This way, you dont have to repeat .json() everywhere (but ok, you have yet to repeat the named reference :-$ )

Answer 2

Using interceptors (Based on Claus Ibsen's comment)

new RouteBuilder() {
    @Override
    public void configure() throws Exception {

        // interceptors
        interceptSendToEndpoint("activemq:queue:*")
            .marshal()
            .json();

        interceptFrom("activemq:queue:*")
            .unmarshal()
            .json();

        // routes
        from("...")
            .process(...)
            .to("activemq:queue:...");

        from("activemq:queue:...")
            .process(...)
            .to("...");
    }
}

Notes:

1. interceptors have to be defined before any routes in RouteBuilder . Otherwise IllegalArgumentException is thrown explaining situation.
2. interceptors are not shared and have to be defined in each RouteBuilder .