Pablo Fernandez

Tag: Java

  • Printing the class-path in Clojure

    Let’s compare how we print the class-path in Clojure and how we do it on Java.

    In Clojure:

    [sourcecode lang=”clojure”]
    (println (seq (.getURLs (java.lang.ClassLoader/getSystemClassLoader))))
    [/sourcecode]

    In Java:

    [sourcecode lang=”clojure”]
    import java.net.URL;
    import java.net.URLClassLoader;

    public class PrintClasspath {
    public static void main(String[] args) {
    //Get the System Classloader
    ClassLoader sysClassLoader = ClassLoader.getSystemClassLoader();

    //Get the URLs
    URL[] urls = ((URLClassLoader)sysClassLoader).getURLs();

    for(int i=0; i< urls.length; i++)
    {
    System.out.println(urls[i].getFile());
    }
    }
    }
    [/sourcecode]

    To be fair, the output is not the same, but the effect is.

  • Hacking on the Clojure application

    Being able to write, build and run a Clojure application, like I explained in a previous article, is not enough. You also want to hack on it, to iterative code on it, after all, you are using a Lisp.

    What I mean by iterative coding is something not very few know or do, but it’s extremely common in Lisp. You have you REPL running all the time (that is, generally, the interpreter). You load the code into the REPL, run it, modify some part of the code and re-load it. You may not reload the whole file but only a function on it, and you may have background process running on the REPL, like a web server. It is very powerful. (more…)

  • How to create a Clojure application

    Update: this is not my preferred way to create a Clojure application and shouldn’t be yours either, check out Leiningen

    This is one of those posts that I publish partly for myself. And partly so people can criticize my way, which is also for myself, and only incidentally for others to learn from it.

    It seems Maven is popular in the Clojure world. Clojure itself uses it, Webjure uses and its demo application uses it as well, there’s a branch for Compojure that uses too. So after building all those components using Maven I’ve decided to use it myself when building Clojure applications.
    (more…)