Lightweight, time-proven approach to Java scripting

While recovering from mild surgery, I stumbled upon a post from Paris Apostolopoulos regarding the fact that the name Javascript is a bit misleading. I know there is a lot of media driven support towards Ruby, Groovy and similar “new” scripting languages, but I still find it natural to use Javascript as my preferred scripting language if I need Java libraries.

For this I use Mozilla Rhino, an open-source implementation of JavaScript written entirely in Java. Basically with Rhino you can import Java classes in your in your scripts and create objects.Here is a piece of Javascript (Rhino) code that uses the JasperReports (java) libraries:

importPackage(Packages.net.sf.jasperreports.engine);
importPackage(Packages.net.sf.jasperreports.engine.data);
importPackage(Packages.net.sf.jasperreports.engine.xml);
importPackage(Packages.net.sf.jasperreports.engine["export"]);
…
var jasperDesign = new JRXmlLoader.load(getInputStream(documentURI));
var jasperReport = new JasperCompileManager.compileReport(jasperDesign);
var jasperPrint = new JasperFillManager.fillReport(jasperReport,
           new Packages.java.util.HashMap(), dbConn);
new JasperExportManager.exportReportToHtmlFile(jasperPrint, “myreport.html");

There are a lot of things to consider when choosing a scripting language and I’m sure that there will be people saying that Ruby is better in this way or Groovy in another way but Javascript/Rhino feels natural and has the minimal learning curve due to the similar syntax.

BTW the Rhino engine is an integral part of Apache Cocoon that supports continuations.

UPDATE: Read Stevey’s blog on “Rhino on Rails”