Overriding a java protected method and calling the super-class method from within

[László Török]

Hi,

I am quite new to clojure and in the process of sharpening my skills. I bumped into an interop problem:

I have a Java concrete class A that has a protectedMethod(parameter). I'd like to wrap the method, but also call the one defined in the super class.

I found that (proxy ..) is no good for this, I was trying to figure out gen-class, but seem quite a hassle. Particularly, I don't know how to call the method in the super class i.e. what is the equivalent for super.protectedMethod(..) within the context of gen-class.

Anybody has a clue?

Thanks a lot.

Las

[.Bill Smith]

There may be others, but one way to do it is to the Java reflection API to call the super class method through its Method object.

Bill

[Stuart Sierra]

Accessing protected methods is a pain. You could do it with reflection, as Bill said.

In gen-class, you need to add the `:exposes-methods` option to gen-class. This will make the protected method available as a public method, under an alternate name.

For example, if you're extending Java class A which has protectedMethod(parameter), you would have something like:

    (ns com.example.subclass-of-A

      (:gen-class :extends com.example.A

         :exposes-methods {protectedMethod exposedSuperMethod}))

    

    (defn -protectedMethod [this parameter]

      (.exposedSuperMethod this parameter))

-Stuart Sierra

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