interface-test.clj

(ns ramlpg.core
  (:import [org.raml.v2.api RamlModelBuilder]
           [org.raml.v2.internal.impl.commons.model.type
            TypeDeclaration
            FileTypeDeclaration
            ArrayTypeDeclaration ObjectTypeDeclaration]))

(defn parse-raml [raml-resource]
  (let [api (.buildApi (RamlModelBuilder.) raml-resource)]
    (println (.isVersion10 api))
    (println (.isVersion08 api))
    (println (.hasErrors api))
    (.getApiV10 api)))

(defonce api (parse-raml "resources/api.raml"))


;; relevant part of the code
(doseq [s (seq (.types api))]
  (println s)
  (println (type s))
  (println (instance? FileTypeDeclaration s)))

output.txt

#object[com.sun.proxy.$Proxy10 0x56e1b91a org.raml.v2.internal.impl.commons.model.type.FileTypeDeclaration@2f929b72]
com.sun.proxy.$Proxy10
false
#object[com.sun.proxy.$Proxy10 0x565d5a5c org.raml.v2.internal.impl.commons.model.type.FileTypeDeclaration@4a7bd89a]
com.sun.proxy.$Proxy10
false
#object[com.sun.proxy.$Proxy11 0x5eb7d0da org.raml.v2.internal.impl.commons.model.type.UnionTypeDeclaration@772d192]
com.sun.proxy.$Proxy11
false