Clojure reify a Java interface with overloaded methods - clojure

Question

I'm trying to implement the following Java interface in Clojure:
package quickfix;
public interface MessageFactory {
Message create(String beginString, String msgType);
Group create(String beginString, String msgType, int correspondingFieldID);
}
The following Clojure code is my attempt at doing this:
(defn -create-message-factory
[]
(reify quickfix.MessageFactory
(create [beginString msgType]
nil)
(create [beginString msgType correspondingFieldID]
nil)))
This fails to compile with the error:
java.lang.IllegalArgumentException: Can't define method not in interfaces: create
The documentation suggests overloaded interface methods are ok, so long as the arity is different as it is in this case:
If a method is overloaded in a protocol/interface, multiple
independent method definitions must be supplied. If overloaded with
same arity in an interface you must specify complete hints to
disambiguate - a missing hint implies Object.
How can I get this working?

Answer 1

You're missing a parameter. The first parameter of every method implemented by reify is the object itself (as is the case with defrecord/deftype). So, try this:
(defn -create-message-factory
[]
(reify quickfix.MessageFactory
(create [this beginString msgType]
nil)
(create [this beginString msgType correspondingFieldID]
nil)))