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clojure

can I define a java interface in Clojure?

I would like to define a java interface, in clojure - (as well as implement it) - I understand implementing can be done via both proxy and gen-class, but that always assumed the interface was already defined.

Solution

  • You can generate a Java interface with both clojure.core/definterface and clojure.core/gen-interface. (definterface expands to a call to gen-interface.)

    (ns demo.api)

(definterface Store
  (^demo.api.Store buy [])
  (^demo.api.Store buy [^int q])
  (^demo.api.Store sell [])
  (^int getQty []))

;; or

(gen-interface
 :name demo.api.Store
 :methods [[buy [] demo.api.Store]
           [buy [int] demo.api.Store]
           [sell [] demo.api.Store]
           [getQty [] int]])

    Sampled from this blog post.

    If you want an "Interface", in the generic sense, then take a look at Clojure Protocols.