How to get an Fn which calls a Java method?

Question

I\'m learning Clojure. I wrote this code to recursively walk a directory.

(tree-seq #(.isDirectory %1) #(.listFiles %1) (File. \"/my-directory\"))
         


        

Answer 1

Java methods aren't clojure functions because you can't call a method on its own; you have to call a method on an object, and it has to be an object of the type that the method expects. In other words, in java, a method cannot be fully separated from its defining class (at least not efficiently).

An alternative to #(.foo %) would be (memfn foo), which hardly anyone uses anymore after #(...) was introduced.