QCon 2007 Notes: JRuby

Rob Harrop, Java and Ruby: Practical Techniques for Using JRuby

  • RH plugged The Ruby Way as a good book for learners from Java, very task-focused
  • JRuby can put a really nice API around the rather clunky JMX API, or simpler builders for Swing panels: in fact, a neat general use for JRuby is to create DSLs to wrap painful Java APIs.
  • RH noted he had also seen absolute disaster when people tried to DSL their entire domain at once
  • Three ways of integrating JRuby code with Java:
    • BSF (RH: simple, but not particularly powerful)
    • The JRuby API (RH: note entirely clear or documented)
    • Spring from 2.0.2 fully wraps JRuby; in spring.xml you just identify the bean with the lang:jruby element instead of the bean element. (You can also include a refresh-check-delay attribute for dynamically reloading scripts
  • Some really neat advantages to JRuby
    • Operator overloading
    • Blocks
      • With JRuby DSLs we can structurally encapsulate really complex conditional logic and keep it in simple rule blocks
    • method_missing
    • Dynamic extension (we can change classes and methods on the fly)
      • If that’s too scary, you can also take a single instance of a class and add methods only to that object on the fly
  • Note that the Groovy integration with Java is a lot nicer and tighter than JRuby’s, and that error propagation from JRuby to Java is “a whole new world of awful”

It's only fair to share...
Share on Facebook
Facebook
Google+
Google+
Tweet about this on Twitter
Twitter
Share on LinkedIn
Linkedin

Leave a Reply