Al Clojure 1.6, l'approccio preferito sarebbe il seguente. Supponendo di avere, sul classpath, il vaso Clojure 1.6 e il seguente file clojure (o il suo equivalente compilato):
(ns my.clojure.namespace
(:import [my.java.package Doer]))
(defn reify-doer
"Some docstring about what this specific implementation of Doer
does differently than the other ones. For example, this one does
not actually do anything but print the given string to stdout."
[]
(reify
Doer
(doSomethin [this in] (println in))))
poi, da Java, è possibile accedere come segue:
package my.other.java.package.or.maybe.the.same.one;
import my.java.package.Doer;
import clojure.lang.IFn;
import clojure.java.api.Clojure;
public class ClojureDoerUser {
// First, we need to instruct the JVM to compile/load our
// Clojure namespace. This should, obviously, only be done once.
static {
IFn require = Clojure.var("clojure.core", "require");
require.invoke(Clojure.read("my.clojure.namespace"));
// Clojure.var() does a somewhat expensive lookup; if we had more than
// one Clojure namespace to load, so as a general rule its result should
// always be saved into a variable.
// The call to Clojure.read is necessary because require expects a Clojure
// Symbol, for which there is no more direct official Clojure API.
}
// We can now lookup the function we want from our Clojure namespace.
private static IFn doerFactory = Clojure.var("my.clojure.namespace", "reify-doer");
// Optionally, we can wrap the doerFactory IFn into a Java wrapper,
// to isolate the rest of the code from our Clojure dependency.
// And from the need to typecast, as IFn.invoke() returns Object.
public static Doer createDoer() {
return (Doer) doerFactory.invoke();
}
public static void main(String[] args) {
Doer doer = (Doer) doerFactory.invoke();
doer.doSomethin("hello, world");
}
}
fonte
2014-05-11 17:06:12
grazie tutti per avermi aiutato! Ho finito per usare Reify e ho appena scritto la funzione principale in clojure. il clojure è incredibilmente interessante! –