Use Java object as Clojure map

Question

I have a Java class that I'd like to use in Clojure. But, I want to use it as a Clojure map. What are the steps required to do so?

I've looked at the code for IPersistentMap -- should the Java class implement that? Or should there be some Clojure code which implements a protocol?

I know I could just write some mapping code, to explicitly convert the code from Java objects to maps, but that solution has a high effort/reward ratio. Also, I might encounter this same situation many more times.

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Concrete example: I have a parser written in Java. I'd like to use that to parse some text, and then access the contents of the parsed data structure as though it were in Clojure maps:

(def parser (new MyParser))

(let [parse-tree (parser ... parse some text ...)]
  ((parse-tree :items) "itemid"))

Answer 1

The function bean came to mind:

Takes a Java object and returns a read-only implementation of the map abstraction based upon its JavaBean properties.

Example taken from the site:

user=> (import java.util.Date)
java.util.Date

user=> (def *now* (Date.))
#'user/*now*

user=> (bean *now*)
{:seconds 57, :date 13, :class java.util.Date,
 :minutes 55, :hours 17, :year 110, :timezoneOffset -330,
 :month 6, :day 2, :time 1279023957492}