Question

If I have an OrderHandler interface:

public interface OrderHandler {
    public void handle(Order order);
}

And have several implementations (DefaultOrderHandler, ComplexOrderHandler, SpecialOrderHandler, etc.) of it, how do I specify which one to use in Camel’s SimpleRegistry? For instance, if I have the following route:

from("direct:pointA")
    .bean(OrderHandler.class)
    .to("direct:pointB");

How do I specify a SimpleRegistry, and how do I configure that registry to “inject” a DefaultOrderHandler when I specify a processor of type bean(OrderHandler.class)?

I ask because it would be nice (for unit testing) to be able to inject a DummyOrderHandler during testing, and a real impl during production. Thanks in advance!

Answer 1

When using

bean(MyClass.class)

Then usually the class type (eg MyClass.class) must be a class (not abstract, not interface) as Camel will use that to instantiate an instance.

However if the method that is being invoked is a static method, then Camel does not need to instantiate an object, and therefore the class can be abstract etc. You can supply the method name as a 2nd parameter to pint point which method to call.

In your case have 3 different implementations of an interface. You need to specify the type to use

bean(MyImpl.class)

Or refer to a bean by a name to lookup in the registry, or provide an object instance
For example:

OrderHandler handler  = new DummyOrderHandler;
...
bean(handler)

As its just Java code, and if you are using RouteBuilder then you can juse have getter/setter for OrderHandler, and then set the desired implementation on RouteBuilder

RouteBuilder myBuilder = new MyRouteBuilder();
myBuilder.setOrderHandler(new DummyOrderHandler());
...

And then in the configure method in MyRouteBuilder you can use

bean(handler)