How to distinguish java map from clojure map?

Question

Let's say I have the following code:

(def m1 (java.util.HashMap.))
(def m2 (java.util.LinkedHashMap.))
(def m3 {})

I need a function that will allow me to detect maps that came from java, e.g.:

(map java-map? [m1 m2 m3]) ;; => (true true false)

Anything out of the box?

Answer 1

i would do this:

user=> (defn java-map? [m] 
         (and (instance? java.util.Map m) 
              (not (map? m))))
#'user/java-map?

user=> (java-map? {})
false

user=> (java-map? (java.util.HashMap.))
true

user=> (java-map? [])
false

so you just check that it implements core java's Map interface, but not being a clojure's persistent map.